diff --git a/package-lock.json b/package-lock.json
index 514bc7c76d..7b7b522b3b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,7 +19,7 @@
         "@fortawesome/free-solid-svg-icons": "^6.0.0",
         "@fortawesome/react-fontawesome": "^0.1.17",
         "@terrestris/base-util": "^1.0.1",
-        "@terrestris/ol-util": "^5.1.0",
+        "@terrestris/ol-util": "^6.0.0",
         "@types/geojson": "^7946.0.8",
         "@types/lodash": "^4.14.179",
         "@types/moment": "^2.13.0",
@@ -3642,9 +3642,9 @@
       }
     },
     "node_modules/@terrestris/ol-util": {
-      "version": "5.1.0",
-      "resolved": "https://registry.npmjs.org/@terrestris/ol-util/-/ol-util-5.1.0.tgz",
-      "integrity": "sha512-IDmqh0H47uSmtZWAWYzILW1Vi4CUvUKgIhL5Vj3OgQ+mYA4k9vL3QvisRWxun3cH6Ra1fgTDy+39i7AT953QdA==",
+      "version": "6.0.0",
+      "resolved": "https://registry.npmjs.org/@terrestris/ol-util/-/ol-util-6.0.0.tgz",
+      "integrity": "sha512-99km/hVLd0JS6y7zCNnD1Bf9IW2lpiUWfKcawvhkyVkEujsSP4zlgl6QwCiYgWQYUsoCAyNZHeiFVoXklEwW+A==",
       "dependencies": {
         "@terrestris/base-util": "^1.0.1",
         "@turf/turf": "^6.5.0",
@@ -3662,6 +3662,18 @@
         "ol": "^6.5"
       }
     },
+    "node_modules/@terrestris/ol-util/node_modules/typescript": {
+      "version": "4.6.2",
+      "resolved": "https://registry.npmjs.org/typescript/-/typescript-4.6.2.tgz",
+      "integrity": "sha512-HM/hFigTBHZhLXshn9sN37H085+hQGeJHJ/X7LpBWLID/fbc2acUMfU+lGD98X81sKP+pFa9f0DZmCwB9GnbAg==",
+      "bin": {
+        "tsc": "bin/tsc",
+        "tsserver": "bin/tsserver"
+      },
+      "engines": {
+        "node": ">=4.2.0"
+      }
+    },
     "node_modules/@testing-library/dom": {
       "version": "8.11.3",
       "resolved": "https://registry.npmjs.org/@testing-library/dom/-/dom-8.11.3.tgz",
diff --git a/package.json b/package.json
index 952462cdab..0010101b2b 100644
--- a/package.json
+++ b/package.json
@@ -86,7 +86,7 @@
     "@fortawesome/free-solid-svg-icons": "^6.0.0",
     "@fortawesome/react-fontawesome": "^0.1.17",
     "@terrestris/base-util": "^1.0.1",
-    "@terrestris/ol-util": "^5.1.0",
+    "@terrestris/ol-util": "^6.0.0",
     "@types/geojson": "^7946.0.8",
     "@types/lodash": "^4.14.179",
     "@types/moment": "^2.13.0",
diff --git a/src/Button/CopyButton/CopyButton.tsx b/src/Button/CopyButton/CopyButton.tsx
index 9660b95584..a99b5c6287 100644
--- a/src/Button/CopyButton/CopyButton.tsx
+++ b/src/Button/CopyButton/CopyButton.tsx
@@ -64,7 +64,7 @@ const CopyButton: React.FC<CopyButtonProps> = ({
 
     const feat = event.selected[0];
 
-    if (!feat || !layers) {
+    if (!feat || !layers || !map) {
       return;
     }
 
diff --git a/src/Button/DigitizeButton/DigitizeButton.tsx b/src/Button/DigitizeButton/DigitizeButton.tsx
index 9483d665ba..5ef4fef0b6 100644
--- a/src/Button/DigitizeButton/DigitizeButton.tsx
+++ b/src/Button/DigitizeButton/DigitizeButton.tsx
@@ -13,12 +13,13 @@ import OlStyleFill from 'ol/style/Fill';
 import OlStyleCircle from 'ol/style/Circle';
 import OlStyleText from 'ol/style/Text';
 import OlInteractionDraw, { createBox, DrawEvent as OlDrawEvent} from 'ol/interaction/Draw';
-import OlInteractionSelect from 'ol/interaction/Select';
-import OlInteractionModify from 'ol/interaction/Modify';
-import OlInteractionTranslate from 'ol/interaction/Translate';
+import OlInteractionSelect, { SelectEvent as OlSelectEvent } from 'ol/interaction/Select';
+import OlInteractionModify, { ModifyEvent as OlModifyEvent } from 'ol/interaction/Modify';
+import OlInteractionTranslate, { TranslateEvent as OlTranslateEvent } from 'ol/interaction/Translate';
 import OlFeature from 'ol/Feature';
 import * as OlEventConditions from 'ol/events/condition';
 import OlGeometry from 'ol/geom/Geometry';
+import OlMapBrowserEvent from 'ol/MapBrowserEvent';
 
 import _isFunction from 'lodash/isFunction';
 import _isArray from 'lodash/isArray';
@@ -30,6 +31,7 @@ import AnimateUtil from '@terrestris/ol-util/dist/AnimateUtil/AnimateUtil';
 import Logger from '@terrestris/base-util/dist/Logger';
 
 import { CSS_PREFIX } from '../../constants';
+import { ChangeEvent } from 'react';
 
 interface DefaultProps {
   /**
@@ -524,7 +526,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
       map
     } = this.props;
 
-    let digitizeLayer = MapUtil.getLayerByName(map, digitizeLayerName);
+    let digitizeLayer = digitizeLayerName ? MapUtil.getLayerByName(map, digitizeLayerName) : null;
 
     if (!digitizeLayer) {
       digitizeLayer = new OlLayerVector({
@@ -552,20 +554,21 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    * @param feature The feature which is being styled.
    * @return The style to use.
    */
-  digitizeStyleFunction = feature => {
+  digitizeStyleFunction = (feature: OlFeature<OlGeometry>) => {
     const {
       drawStyle,
     } = this.props;
 
-    if (!feature.getGeometry()) {
-      return null;
+    const geometry = feature.getGeometry();
+    if (!geometry) {
+      return undefined;
     }
 
     if (drawStyle) {
       return _isFunction(drawStyle) ? drawStyle(feature) : drawStyle;
     }
 
-    switch (feature.getGeometry().getType()) {
+    switch (geometry.getType()) {
       case DigitizeButton.POINT_DRAW_TYPE: {
         if (!feature.get('isLabel')) {
           return new OlStyleStyle({
@@ -617,7 +620,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
         });
       }
       default:
-        return null;
+        return undefined;
     }
   };
 
@@ -690,9 +693,6 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
   /**
    * Creates a correctly configured OL draw interaction depending on given
    * drawType and adds this to the map.
-   *
-   * @param pressed Whether the digitize button is pressed or not.
-   * Will be used to handle active state of the draw interaction.
    */
   createDrawInteraction = () => {
     const {
@@ -708,7 +708,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
     }
 
     const drawInteractionName = `react-geo-draw-interaction-${drawType}`;
-    let drawInteraction = MapUtil.getInteractionsByName(map, drawInteractionName)[0];
+    let drawInteraction = MapUtil.getInteractionsByName(map, drawInteractionName)[0] as OlInteractionDraw;
 
     if (!drawInteraction) {
       let type = drawType;
@@ -735,18 +735,12 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
         drawInteraction.on('drawend', this.handleTextAdding);
       }
 
-      drawInteraction.on('drawend', (evt) => {
-        const onDrawEnd = this.getOnDrawEnd();
-        if (onDrawEnd) {
-          onDrawEnd(evt);
-        }
+      drawInteraction.on('drawend', (evt: OlDrawEvent) => {
+        this.getOnDrawEnd()?.(evt);
       });
 
-      drawInteraction.on('drawstart', (evt) => {
-        const onDrawStart = this.getOnDrawStart();
-        if (onDrawStart) {
-          onDrawStart(evt);
-        }
+      drawInteraction.on('drawstart', (evt: OlDrawEvent) => {
+        this.getOnDrawStart()?.(evt);
       });
 
       drawInteraction.setActive(false);
@@ -774,7 +768,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
     }
 
     const selectInteractionName = `react-geo-select-interaction-${editType}`;
-    let selectInteraction: OlInteractionSelect = MapUtil.getInteractionsByName(map, selectInteractionName)[0];
+    let selectInteraction = MapUtil.getInteractionsByName(map, selectInteractionName)[0] as OlInteractionSelect;
 
     if (!selectInteraction) {
       selectInteraction = new OlInteractionSelect({
@@ -819,7 +813,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
     }
 
     const modifyInteractionName = `react-geo-modify-interaction-${editType}`;
-    let modifyInteraction = MapUtil.getInteractionsByName(map, modifyInteractionName)[0];
+    let modifyInteraction = MapUtil.getInteractionsByName(map, modifyInteractionName)[0] as OlInteractionModify;
 
     if (!modifyInteraction) {
       modifyInteraction = new OlInteractionModify({
@@ -857,7 +851,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
     }
 
     const translateInteractionName = `react-geo-translate-interaction-${editType}`;
-    let translateInteraction = MapUtil.getInteractionsByName(map, translateInteractionName)[0];
+    let translateInteraction = MapUtil.getInteractionsByName(map, translateInteractionName)[0] as OlInteractionTranslate;
 
     if (!translateInteraction) {
       translateInteraction = new OlInteractionTranslate({
@@ -885,7 +879,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onFeatureRemove = evt => {
+  onFeatureRemove = (evt: OlSelectEvent) => {
     const {
       onFeatureRemove,
       onFeatureSelect
@@ -919,7 +913,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onFeatureCopy = evt => {
+  onFeatureCopy = (evt: OlSelectEvent) => {
     const {
       map,
       onFeatureCopy,
@@ -928,7 +922,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
 
     const feat = evt.selected[0];
 
-    if (!feat || !this._digitizeFeatures) {
+    if (!feat || !this._digitizeFeatures || !this._digitizeLayer) {
       return;
     }
 
@@ -962,7 +956,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onModifyStart = evt => {
+  onModifyStart = (evt: OlModifyEvent) => {
     const {
       onModifyStart
     } = this.props;
@@ -971,7 +965,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
       onModifyStart(evt);
     }
 
-    const feature = evt.features.getArray()[0];
+    const feature = evt.features.getArray()[0] as OlFeature<OlGeometry>;
 
     if (feature.get('isLabel')) {
       this._digitizeTextFeature = feature;
@@ -997,7 +991,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onModifyEnd = evt => {
+  onModifyEnd = (evt: OlModifyEvent) => {
     const {
       onModifyEnd
     } = this.props;
@@ -1012,7 +1006,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onTranslateStart = evt => {
+  onTranslateStart = (evt: OlTranslateEvent) => {
     const {
       onTranslateStart
     } = this.props;
@@ -1027,7 +1021,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onTranslateEnd = evt => {
+  onTranslateEnd = (evt: OlTranslateEvent) => {
     const {
       onTranslateEnd
     } = this.props;
@@ -1042,7 +1036,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The interaction event.
    */
-  onTranslating = evt => {
+  onTranslating = (evt: OlTranslateEvent) => {
     const {
       onTranslating
     } = this.props;
@@ -1146,7 +1140,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    * @param evt Input event containing new text value to be set as
    * textLabel.
    */
-  onLabelChange = evt => {
+  onLabelChange = (evt: ChangeEvent<HTMLTextAreaElement>) => {
     this.setState({
       textLabel: evt.target.value
     });
@@ -1158,7 +1152,7 @@ class DigitizeButton extends React.Component<DigitizeButtonProps, DigitizeButton
    *
    * @param evt The `pointermove` event.
    */
-  onPointerMove = evt => {
+  onPointerMove = (evt: OlMapBrowserEvent<PointerEvent>) => {
     if (evt.dragging) {
       return;
     }
diff --git a/src/Button/DrawButton/DrawButton.tsx b/src/Button/DrawButton/DrawButton.tsx
index 8c1699574b..364c0c9310 100644
--- a/src/Button/DrawButton/DrawButton.tsx
+++ b/src/Button/DrawButton/DrawButton.tsx
@@ -15,6 +15,7 @@ import { CSS_PREFIX } from '../../constants';
 import { useMap } from '../../Hook/useMap';
 import { DigitizeUtil } from '../../Util/DigitizeUtil';
 import { FeatureLabelModal } from '../../FeatureLabelModal/FeatureLabelModal';
+import { EventsKey } from 'ol/events';
 
 type DrawType = 'Point' | 'LineString' | 'Polygon' | 'Circle' | 'Rectangle' | 'Text';
 
@@ -165,7 +166,7 @@ const DrawButton: React.FC<DrawButtonProps> = ({
 
     setDrawInteraction(newInteraction);
 
-    let key;
+    let key: EventsKey;
 
     if (drawType === 'Text') {
       key = newInteraction.on('drawend', evt => {
diff --git a/src/Button/GeoLocationButton/GeoLocationButton.tsx b/src/Button/GeoLocationButton/GeoLocationButton.tsx
index 119f0fc6ea..7dcbb53d00 100644
--- a/src/Button/GeoLocationButton/GeoLocationButton.tsx
+++ b/src/Button/GeoLocationButton/GeoLocationButton.tsx
@@ -273,30 +273,28 @@ class GeoLocationButton extends React.Component<GeoLocationButtonProps> {
 
   // recenters the view by putting the given coordinates at 3/4 from the top or
   // the screen
-  getCenterWithHeading = (position, rotation, resolution) => {
+  getCenterWithHeading = (position: [number, number], rotation: number, resolution: number) => {
     const size = this.props.map.getSize() ?? [0, 0];
     const height = size[1];
 
     return [
-      position[0] - Math.sin(rotation) * height * resolution * 1 / 4,
-      position[1] + Math.cos(rotation) * height * resolution * 1 / 4
+      position[0] - Math.sin(rotation) * height * resolution / 4,
+      position[1] + Math.cos(rotation) * height * resolution / 4
     ];
   };
 
   updateView = () => {
     const view = this.props.map.getView();
     const deltaMean = 500; // the geolocation sampling period mean in ms
-    let previousM = 0;
     // use sampling period to get a smooth transition
     let m = Date.now() - deltaMean * 1.5;
-    m = Math.max(m, previousM);
+    m = Math.max(m, 0);
 
-    previousM = m;
     // interpolate position along positions LineString
     const c = this._positions.getCoordinateAtM(m, true);
     if (c) {
       if (this.props.follow) {
-        view.setCenter(this.getCenterWithHeading(c, -c[2], view.getResolution()));
+        view.setCenter(this.getCenterWithHeading([c[0], c[1]], -c[2], view.getResolution() ?? 0));
         view.setRotation(-c[2]);
       }
       if (this.props.showMarker) {
diff --git a/src/Button/MeasureButton/MeasureButton.tsx b/src/Button/MeasureButton/MeasureButton.tsx
index 6b1d235431..4b1a9e2b71 100644
--- a/src/Button/MeasureButton/MeasureButton.tsx
+++ b/src/Button/MeasureButton/MeasureButton.tsx
@@ -462,10 +462,8 @@ class MeasureButton extends React.Component<MeasureButtonProps> {
 
   /**
    * Called if the current geometry of the draw interaction has changed.
-   *
-   * @param evt The generic change event.
    */
-  onDrawInteractionGeometryChange(/* evt*/) {
+  onDrawInteractionGeometryChange() {
     this.updateMeasureTooltip();
   }
 
@@ -608,8 +606,8 @@ class MeasureButton extends React.Component<MeasureButtonProps> {
       }
 
       const value = measureType === 'line' ?
-        MeasureUtil.formatLength(geom, map, decimalPlacesInTooltips, geodesic) :
-        MeasureUtil.formatArea(geom, map, decimalPlacesInTooltips, geodesic);
+        MeasureUtil.formatLength(geom as OlGeomLineString, map, decimalPlacesInTooltips, geodesic) :
+        MeasureUtil.formatArea(geom as OlGeomPolygon, map, decimalPlacesInTooltips, geodesic);
 
       if (parseInt(value, 10) > 0) {
         const div = document.createElement('div');
@@ -843,13 +841,15 @@ class MeasureButton extends React.Component<MeasureButtonProps> {
         if (measureType === 'line') {
           output = MeasureUtil.formatLength(geom, map, decimalPlacesInTooltips, geodesic);
         } else if (measureType === 'angle') {
-          output = MeasureUtil.formatAngle(geom, map, decimalPlacesInTooltips);
+          output = MeasureUtil.formatAngle(geom, 0);
         }
       } else {
         return;
       }
 
-      this._measureTooltipElement.innerHTML = output;
+      if (output) {
+        this._measureTooltipElement.innerHTML = output;
+      }
       this._measureTooltip?.setPosition(measureTooltipCoord);
     }
   }
diff --git a/src/Button/ToggleGroup/ToggleGroup.tsx b/src/Button/ToggleGroup/ToggleGroup.tsx
index b36b50c19b..eb5290b614 100644
--- a/src/Button/ToggleGroup/ToggleGroup.tsx
+++ b/src/Button/ToggleGroup/ToggleGroup.tsx
@@ -6,6 +6,7 @@ import _isFunction from 'lodash/isFunction';
 import { CSS_PREFIX } from '../../constants';
 
 import './ToggleGroup.less';
+import { ToggleButtonProps } from '../ToggleButton/ToggleButton';
 
 export interface ToggleGroupProps {
   /**
@@ -124,7 +125,7 @@ class ToggleGroup extends React.Component<ToggleGroupProps, ToggleGroupState> {
    *
    * @param childProps The properties of the children.
    */
-  onChange = (childProps) => {
+  onChange = (childProps: ToggleButtonProps) => {
     if (_isFunction(this.props.onChange)) {
       this.props.onChange(childProps);
     }
diff --git a/src/Container/AddWmsPanel/AddWmsLayerEntry/AddWmsLayerEntry.tsx b/src/Container/AddWmsPanel/AddWmsLayerEntry/AddWmsLayerEntry.tsx
index 1a33a42cb8..b02dbe3a0c 100644
--- a/src/Container/AddWmsPanel/AddWmsLayerEntry/AddWmsLayerEntry.tsx
+++ b/src/Container/AddWmsPanel/AddWmsLayerEntry/AddWmsLayerEntry.tsx
@@ -47,7 +47,7 @@ export class AddWmsLayerEntry extends React.Component<AddWmsLayerEntryProps, Add
    */
   static defaultProps = {
     layerQueryableText: 'Layer is queryable',
-    layerTextTemplateFn: (wmsLayer) => {
+    layerTextTemplateFn: (wmsLayer: WmsLayer) => {
       const title = wmsLayer.get('title');
       const abstract = wmsLayer.get('abstract');
       return abstract ?
diff --git a/src/Field/CoordinateReferenceSystemCombo/CoordinateReferenceSystemCombo.tsx b/src/Field/CoordinateReferenceSystemCombo/CoordinateReferenceSystemCombo.tsx
index 88f317a9b7..5ab62f6256 100644
--- a/src/Field/CoordinateReferenceSystemCombo/CoordinateReferenceSystemCombo.tsx
+++ b/src/Field/CoordinateReferenceSystemCombo/CoordinateReferenceSystemCombo.tsx
@@ -118,7 +118,7 @@ class CoordinateReferenceSystemCombo extends React.Component<CRSComboProps, CRSC
   transformResults = (json: any): CrsDefinition[] => {
     const results = json.results;
     if (results && results.length > 0) {
-      return results.map(obj => ({code: obj.code, value: obj.name, proj4def: obj.proj4, bbox: obj.bbox}));
+      return results.map((obj: any) => ({code: obj.code, value: obj.name, proj4def: obj.proj4, bbox: obj.bbox}));
     } else {
       return [];
     }
diff --git a/src/Field/NominatimSearch/NominatimSearch.tsx b/src/Field/NominatimSearch/NominatimSearch.tsx
index 80f887a29c..19f1e08f47 100644
--- a/src/Field/NominatimSearch/NominatimSearch.tsx
+++ b/src/Field/NominatimSearch/NominatimSearch.tsx
@@ -173,6 +173,7 @@ export class NominatimSearch extends React.Component<NominatimSearchProps, Nomin
      * selected item.
      *
      * @param selected The selected item as it is returned by nominatim.
+     * @param olMap The map
      */
     onSelect: (selected: NominatimPlace, olMap: OlMap) => {
       if (selected && selected.boundingbox) {
@@ -222,7 +223,7 @@ export class NominatimSearch extends React.Component<NominatimSearchProps, Nomin
    *
    * @param prevProps Previous props
    */
-  componentDidUpdate(prevProps) {
+  componentDidUpdate(prevProps: Readonly<NominatimSearchProps>) {
     if (this.props.searchTerm !== prevProps.searchTerm) {
       this.onUpdateInput(this.props.searchTerm);
     }
diff --git a/src/Field/ScaleCombo/ScaleCombo.tsx b/src/Field/ScaleCombo/ScaleCombo.tsx
index bbf39a96e4..87b9240513 100644
--- a/src/Field/ScaleCombo/ScaleCombo.tsx
+++ b/src/Field/ScaleCombo/ScaleCombo.tsx
@@ -4,6 +4,7 @@ const Option = Select.Option;
 
 import OlMap from 'ol/Map';
 import OlView from 'ol/View';
+import OlMapEvent from 'ol/MapEvent';
 
 import _isInteger from 'lodash/isInteger';
 import _isEmpty from 'lodash/isEmpty';
@@ -19,6 +20,7 @@ import MapUtil from '@terrestris/ol-util/dist/MapUtil/MapUtil';
 import { CSS_PREFIX } from '../../constants';
 
 import './ScaleCombo.less';
+import _isNumber from 'lodash/isNumber';
 
 interface ScaleComboProps {
   /**
@@ -111,7 +113,7 @@ class ScaleCombo extends React.Component<ScaleComboProps, ScaleComboState> {
     const defaultOnZoomLevelSelect = (selectedScale: string) => {
       const mapView = props.map.getView();
       const calculatedResolution = MapUtil.getResolutionForScale(
-        selectedScale, mapView.getProjection().getUnits()
+        parseInt(selectedScale, 10), mapView.getProjection().getUnits()
       );
       mapView.setResolution(calculatedResolution);
     };
@@ -180,11 +182,11 @@ class ScaleCombo extends React.Component<ScaleComboProps, ScaleComboState> {
    * @param evt The 'moveend' event
    * @private
    */
-  zoomListener = (evt) => {
-    const zoom = evt.target.getView().getZoom();
-    let roundZoom = Math.round(zoom);
-    if (!roundZoom) {
-      roundZoom = 0;
+  zoomListener = (evt: OlMapEvent) => {
+    const zoom = (evt.target as OlMap).getView().getZoom();
+    let roundZoom = 0;
+    if (_isNumber(zoom)) {
+      roundZoom = Math.round(zoom);
     }
 
     this.setState({
@@ -194,14 +196,14 @@ class ScaleCombo extends React.Component<ScaleComboProps, ScaleComboState> {
 
   /**
    * @function pushScaleOption: Helper function to create a {@link Option} scale component
-   * based on a resolution and the {@link Ol.View}
+   * based on a resolution and the {@link OlView}
    *
    * @param scales The scales array to push the scale to.
    * @param resolution map cresolution to generate the option for
    * @param view The map view
    *
    */
-  pushScale = (scales: string[], resolution: number, view: OlView) => {
+  pushScale = (scales: number[], resolution: number, view: OlView) => {
     const scale = MapUtil.getScaleForResolution(resolution, view.getProjection().getUnits());
     const roundScale = MapUtil.roundScale(scale);
     if (scales.includes(roundScale) ) {
@@ -212,7 +214,7 @@ class ScaleCombo extends React.Component<ScaleComboProps, ScaleComboState> {
 
   /**
    * Generates the scales to add as {@link Option} to the SelectField based on
-   * the given instance of {@link Ol.Map}.
+   * the given instance of {@link OlMap}.
    *
    * @return The array of scales.
    */
@@ -227,7 +229,7 @@ class ScaleCombo extends React.Component<ScaleComboProps, ScaleComboState> {
       return [];
     }
 
-    const scales = [];
+    const scales: number[] = [];
     const view = map.getView();
     // use existing resolutions array if exists
     const resolutions = view.getResolutions();
diff --git a/src/Field/WfsSearchInput/WfsSearchInput.tsx b/src/Field/WfsSearchInput/WfsSearchInput.tsx
index b57d054097..c9b46c5bd5 100644
--- a/src/Field/WfsSearchInput/WfsSearchInput.tsx
+++ b/src/Field/WfsSearchInput/WfsSearchInput.tsx
@@ -15,6 +15,8 @@ import _debounce from 'lodash/debounce';
 import Logger from '@terrestris/base-util/dist/Logger';
 import WfsFilterUtil from '@terrestris/ol-util/dist/WfsFilterUtil/WfsFilterUtil';
 
+import { Feature } from 'geojson';
+
 import { CSS_PREFIX } from '../../constants';
 
 import './WfsSearchInput.less';
@@ -139,12 +141,12 @@ interface OwnProps {
    * Please note: if omitted only data fetch will be performed and no data
    * will be shown afterwards!
    */
-  onFetchSuccess?: (data: any) => void;
+  onFetchSuccess?: (features: Feature[]) => void;
   /**
    * An onFetchError callback function which gets called if data fetch is
    * failed.
    */
-  onFetchError?: (data: any) => void;
+  onFetchError?: (error: string) => void;
   /**
    * Optional callback function, that will be called if 'clear' button of
    * input field was clicked.
@@ -159,7 +161,7 @@ interface OwnProps {
 
 interface WfsSearchState {
   searchTerm: string;
-  data: any[];
+  data: Feature[];
   fetching: boolean;
 }
 
@@ -223,7 +225,7 @@ export class WfsSearchInput extends React.Component<WfsSearchInputProps, WfsSear
    *
    * @param prevProps Previous props
    */
-  componentDidUpdate(prevProps) {
+  componentDidUpdate(prevProps: Readonly<WfsSearchInputProps>) {
     if (this.props.searchTerm !== prevProps.searchTerm) {
       const evt = {
         target: {
@@ -314,18 +316,20 @@ export class WfsSearchInput extends React.Component<WfsSearchInputProps, WfsSear
     if (request) {
       this.setState({
         fetching: true
-      }, () => {
-        fetch(`${baseUrl}`, {
-          method: 'POST',
-          credentials: additionalFetchOptions.credentials
-            ? additionalFetchOptions.credentials
-            : 'same-origin',
-          body: new XMLSerializer().serializeToString(request),
-          ...additionalFetchOptions
-        })
-          .then(response => response.json())
-          .then(this.onFetchSuccess.bind(this))
-          .catch(this.onFetchError.bind(this));
+      }, async () => {
+        try {
+          const response = await fetch(`${baseUrl}`, {
+            method: 'POST',
+            credentials: additionalFetchOptions.credentials
+              ? additionalFetchOptions.credentials
+              : 'same-origin',
+            body: new XMLSerializer().serializeToString(request),
+            ...additionalFetchOptions
+          });
+          this.onFetchSuccess(await response.json());
+        } catch (e) {
+          this.onFetchError(e.getMessage())
+        }
       });
     } else {
       this.onFetchError('Missing GetFeature request parameters');
@@ -343,15 +347,18 @@ export class WfsSearchInput extends React.Component<WfsSearchInputProps, WfsSear
     const {
       onFetchSuccess
     } = this.props;
-    const data = response.features ? response.features : [];
-    data.forEach(feature => feature.searchTerm = this.state.searchTerm);
+    const data: Feature[] = response.features ? response.features : [];
+    for (const feature of data) {
+      if (!feature.properties) {
+        feature.properties = {};
+      }
+      feature.properties.searchTerm = this.state.searchTerm;
+    }
     this.setState({
       data,
       fetching: false
     }, () => {
-      if (onFetchSuccess) {
-        onFetchSuccess(data);
-      }
+      onFetchSuccess?.(data);
     });
   }
 
@@ -371,9 +378,7 @@ export class WfsSearchInput extends React.Component<WfsSearchInputProps, WfsSear
     this.setState({
       fetching: false
     }, () => {
-      if (onFetchError) {
-        onFetchError(error);
-      }
+      onFetchError?.(error);
     });
   }
 
diff --git a/src/Grid/AgFeatureGrid/AgFeatureGrid.tsx b/src/Grid/AgFeatureGrid/AgFeatureGrid.tsx
index e213f1df00..267a46d458 100644
--- a/src/Grid/AgFeatureGrid/AgFeatureGrid.tsx
+++ b/src/Grid/AgFeatureGrid/AgFeatureGrid.tsx
@@ -1,5 +1,6 @@
 /* eslint-disable testing-library/render-result-naming-convention */
 import * as React from 'react';
+import { ReactNode } from 'react';
 
 import OlStyle from 'ol/style/Style';
 import OlStyleFill from 'ol/style/Fill';
@@ -34,7 +35,9 @@ import {
   RowClickedEvent,
   CellMouseOverEvent,
   CellMouseOutEvent,
-  SelectionChangedEvent
+  SelectionChangedEvent,
+  DetailGridInfo,
+  RowNode
 } from '@ag-grid-community/core';
 import _isNil from 'lodash/isNil';
 
@@ -152,8 +155,8 @@ interface OwnProps {
 }
 
 interface AgFeatureGridState {
-  grid: any;
-  selectedRows: any[];
+  grid: DetailGridInfo | null;
+  selectedRows: RowNode[];
 }
 
 export type AgFeatureGridProps = OwnProps & AgGridReactProps;
@@ -242,7 +245,7 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
    * The reference of this grid.
    * @private
    */
-  _ref;
+  _ref: AgGridReact | null;
 
   /**
    * The className added to this component.
@@ -440,13 +443,14 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
       return;
     }
 
+    // @ts-ignore
     const rowRenderer = grid.api.rowRenderer;
 
     features.forEach(feature => {
       const key = this.props.keyFunction(feature);
 
       let rc: any;
-      rowRenderer.forEachRowComp((idx, rowComp) => {
+      rowRenderer.forEachRowComp((idx: number, rowComp: any) => {
         if (rowComp.getRowNode().data.key === key) {
           rc = rowComp;
         }
@@ -469,7 +473,7 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
     selectedFeatures.forEach(feature => {
       const key = this.props.keyFunction(feature);
       let rc: any;
-      rowRenderer.forEachRowComp((idx, rowComp) => {
+      rowRenderer.forEachRowComp((idx: number, rowComp: any) => {
         if (rowComp.getRowNode().data.key === key) {
           rc = rowComp;
         }
@@ -673,12 +677,12 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
    * @param key The feature's key to obtain the row from.
    * @return he row candidate.
    */
-  getRowFromFeatureKey = (key: string) => {
+  getRowFromFeatureKey = (key: string): RowNode | undefined => {
     const {
       grid
     } = this.state;
 
-    let rowNode;
+    let rowNode: RowNode | undefined = undefined;
 
     if (!grid || !grid.api) {
       return;
@@ -912,7 +916,7 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
    */
   onVisiblityChange() {
     if (this.state.grid) {
-      this.state.grid.api.sizeColumnsToFit();
+      this.state.grid.api?.sizeColumnsToFit();
     }
   }
 
@@ -952,15 +956,18 @@ export class AgFeatureGrid extends React.Component<AgFeatureGridProps, AgFeature
     // row by using getRowFromFeatureKey instead.
     let rowClassNameFn;
     if (_isFunction(rowClassName)) {
-      rowClassNameFn = node => {
-        const determinedRowClass = (rowClassName as ((record: any) => string))(node.data);
+      rowClassNameFn = (node: ReactNode) => {
+        const determinedRowClass = rowClassName((node as { data: string }).data);
         return `${this._rowClassName} ${determinedRowClass}`;
       };
     } else {
       const finalRowClassName = rowClassName
         ? `${rowClassName} ${this._rowClassName}`
         : this._rowClassName;
-      rowClassNameFn = node => `${finalRowClassName} ${this._rowKeyClassNamePrefix}${_kebabCase(node.data.key)}`;
+      rowClassNameFn = (node: ReactNode) => {
+        const rowClassSuffix = _kebabCase((node as { data: { key: string } }).data.key);
+        return `${finalRowClassName} ${this._rowKeyClassNamePrefix}${rowClassSuffix}`;
+      };
     }
 
     return (
diff --git a/src/HigherOrderComponent/TimeLayerAware/TimeLayerAware.tsx b/src/HigherOrderComponent/TimeLayerAware/TimeLayerAware.tsx
index 2bac52a17b..48107ec55b 100644
--- a/src/HigherOrderComponent/TimeLayerAware/TimeLayerAware.tsx
+++ b/src/HigherOrderComponent/TimeLayerAware/TimeLayerAware.tsx
@@ -45,7 +45,7 @@ export function timeLayerAware<P>(WrappedComponent: React.ComponentType<P>, laye
 
   return class TimeLayerAware extends React.Component<Omit<P, 'onChange'>> {
 
-    timeChanged = newValues => {
+    timeChanged = (newValues: any) => {
       layers.forEach(config => {
         if (config.isWmsTime) {
           const parms = config.layer.getSource()?.getParams();
diff --git a/src/LayerSwitcher/LayerSwitcher.tsx b/src/LayerSwitcher/LayerSwitcher.tsx
index 0b62846469..f82f08607f 100644
--- a/src/LayerSwitcher/LayerSwitcher.tsx
+++ b/src/LayerSwitcher/LayerSwitcher.tsx
@@ -118,10 +118,9 @@ export class LayerSwitcher extends React.Component<LayerSwitcherProps, LayerSwit
    * @param layer The layer to clone.
    * @returns The cloned layer.
    */
-  cloneLayer = (layer: OlLayerTile<OlTileSource> | OlLayerGroup) => {
-    let layerClone: OlLayerTile<OlTileSource> | OlLayerGroup;
+  cloneLayer (layer: OlLayerTile<OlTileSource> | OlLayerGroup): OlLayerTile<OlTileSource> | OlLayerGroup {
     if (layer instanceof OlLayerGroup) {
-      layerClone = new OlLayerGroup({
+      return new OlLayerGroup({
         layers: layer.getLayers().getArray().map(this.cloneLayer),
         properties: {
           originalLayer: layer
@@ -129,15 +128,14 @@ export class LayerSwitcher extends React.Component<LayerSwitcherProps, LayerSwit
         ...layer.getProperties()
       });
     } else {
-      layerClone = new OlLayerTile({
-        source: layer.getSource() || undefined,
+      return new OlLayerTile({
+        source: (layer as OlLayerTile<OlTileSource>).getSource() || undefined,
         properties: {
           originalLayer: layer
         },
         ...layer.getProperties()
       });
     }
-    return layerClone;
   };
 
   /**
diff --git a/src/LayerTree/LayerTree.spec.tsx b/src/LayerTree/LayerTree.spec.tsx
index 2dd4fee1ef..f4425cc84c 100644
--- a/src/LayerTree/LayerTree.spec.tsx
+++ b/src/LayerTree/LayerTree.spec.tsx
@@ -10,15 +10,17 @@ import TestUtil from '../Util/TestUtil';
 
 import LayerTree from './LayerTree';
 
-import Logger from '@terrestris/base-util/dist/Logger';
+import OlMap from 'ol/Map';
+import OlLayerBase from 'ol/layer/Base';
+import { getUid } from 'ol';
 
 describe('<LayerTree />', () => {
-  let layerGroup;
-  let layerSubGroup;
-  let map;
-  let layer1;
-  let layer2;
-  let layer3;
+  let layerGroup: OlLayerGroup;
+  let layerSubGroup: OlLayerGroup;
+  let map: OlMap;
+  let layer1: OlLayerBase;
+  let layer2: OlLayerBase;
+  let layer3: OlLayerBase;
 
   beforeEach(() => {
     const layerSource1 = new OlSourceTileWMS();
@@ -80,9 +82,10 @@ describe('<LayerTree />', () => {
   });
 
   it('unmount removes listeners', () => {
+    // @ts-ignore
     OlObservable.unByKey = jest.fn();
     const wrapper = TestUtil.mountComponent(LayerTree, {map});
-    const olListenerKeys = wrapper.instance().olListenerKeys;
+    const olListenerKeys = (wrapper.instance() as LayerTree).olListenerKeys;
     wrapper.unmount();
     expect(OlObservable.unByKey).toHaveBeenCalled();
     expect(OlObservable.unByKey).toHaveBeenCalledWith(olListenerKeys);
@@ -96,19 +99,23 @@ describe('<LayerTree />', () => {
     const wrapper = TestUtil.mountComponent(LayerTree, props);
 
     const subLayer = new OlLayerTile({
-      name: 'subLayer',
+      properties: {
+        name: 'subLayer'
+      },
       source: new OlSourceTileWMS()
     });
     const nestedLayerGroup = new OlLayerGroup({
-      name: 'nestedLayerGroup',
+      properties: {
+        name: 'nestedLayerGroup'
+      },
       layers: [subLayer]
     });
 
-    expect(wrapper.instance().olListenerKeys).toHaveLength(10);
+    expect((wrapper.instance() as LayerTree).olListenerKeys).toHaveLength(10);
     wrapper.setProps({
       layerGroup: nestedLayerGroup
     });
-    expect(wrapper.instance().olListenerKeys).toHaveLength(4);
+    expect((wrapper.instance() as LayerTree).olListenerKeys).toHaveLength(4);
   });
 
   describe('<LayerTreeNode> creation', () => {
@@ -155,11 +162,13 @@ describe('<LayerTree />', () => {
         map
       };
       const subLayer = new OlLayerTile({
-        name: 'subLayer',
+        properties: {
+          name: 'subLayer'
+        },
         source: new OlSourceTileWMS()
       });
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
       map.getLayerGroup().setLayers(new OlCollection([subLayer]));
       expect(rebuildSpy).toHaveBeenCalled();
       rebuildSpy.mockRestore();
@@ -172,7 +181,7 @@ describe('<LayerTree />', () => {
       };
       const wrapper = TestUtil.mountComponent(LayerTree, props);
       const treeNodes = wrapper.find('LayerTreeNode');
-      treeNodes.forEach((node, index) => {
+      treeNodes.forEach((node: any, index: number) => {
         const reverseIndex = treeNodes.length - (index + 1);
         const layer = layerGroup.getLayers().item(reverseIndex);
         expect(node.props().title).toBe(layer.get('name'));
@@ -180,7 +189,7 @@ describe('<LayerTree />', () => {
     });
 
     it('accepts a custom title renderer function', () => {
-      const nodeTitleRenderer = function(layer) {
+      const nodeTitleRenderer = function(layer: OlLayerBase) {
         return (
           <span className="span-1">
             <span className="sub-span-1">
@@ -198,7 +207,7 @@ describe('<LayerTree />', () => {
       const wrapper = TestUtil.mountComponent(LayerTree, props);
       const treeNodes = wrapper.find('LayerTreeNode');
 
-      treeNodes.forEach((node, index) => {
+      treeNodes.forEach((node: any, index: number) => {
         const reverseIndex = treeNodes.length - (index + 1);
         const layer = layerGroup.getLayers().item(reverseIndex);
         expect(node.find('span.span-1').length).toBe(1);
@@ -209,7 +218,7 @@ describe('<LayerTree />', () => {
     });
 
     it('can filter layers if a filterFunction is given', () => {
-      const filterFunction = function(layer) {
+      const filterFunction = function(layer: OlLayerBase) {
         return layer.get('name') !== 'layer1';
       };
       const props = {
@@ -231,10 +240,10 @@ describe('<LayerTree />', () => {
       const wrapper = TestUtil.mountComponent(LayerTree, props);
       const treeNodes = wrapper.find('LayerTreeNode');
 
-      treeNodes.forEach((node, index) => {
+      treeNodes.forEach((node: any, index: number) => {
         const reverseIndex = treeNodes.length - (index + 1);
         const layer = layerGroup.getLayers().item(reverseIndex);
-        expect(node.props().eventKey).toBe(layer.ol_uid.toString());
+        expect(node.props().eventKey).toBe(getUid(layer));
       });
     });
 
@@ -246,7 +255,7 @@ describe('<LayerTree />', () => {
       const wrapper = TestUtil.mountComponent(LayerTree, props);
       const treeNodes = wrapper.find('LayerTreeNode');
 
-      treeNodes.forEach((node, index) => {
+      treeNodes.forEach((node: any, index: number) => {
         const reverseIndex = treeNodes.length - (index + 1);
         const layer = layerGroup.getLayers().item(reverseIndex);
         expect(layer.getVisible()).toBe(node.props().checked);
@@ -263,10 +272,10 @@ describe('<LayerTree />', () => {
         layerGroup.setVisible(false);
 
         const wrapper = TestUtil.mountComponent(LayerTree, props);
-        const treeNode = wrapper.instance().treeNodeFromLayer(layer1);
+        const treeNode = (wrapper.instance() as LayerTree).treeNodeFromLayer(layer1);
 
         expect(treeNode.props.title).toBe(layer1.get('name'));
-        expect(treeNode.key).toBe(layer1.ol_uid.toString());
+        expect(treeNode.key).toBe(getUid(layer1));
       });
     });
   });
@@ -281,7 +290,7 @@ describe('<LayerTree />', () => {
       const treeNodes = wrapper.find('LayerTreeNode');
 
 
-      treeNodes.forEach((node, index) => {
+      treeNodes.forEach((node: any, index: number) => {
         const reverseIndex = treeNodes.length - (index + 1);
         const layer = layerGroup.getLayers().item(reverseIndex);
         const checkBox = node.find('.ant-tree-checkbox');
@@ -314,7 +323,7 @@ describe('<LayerTree />', () => {
     });
 
     it('triggers tree rebuild on nodeTitleRenderer changes', () => {
-      const exampleNodeTitleRenderer = function(layer) {
+      const exampleNodeTitleRenderer = function(layer: OlLayerBase) {
         return (
           <span className="span-1">
             {layer.get('name')}
@@ -327,7 +336,7 @@ describe('<LayerTree />', () => {
         map
       };
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
 
       wrapper.setProps({
         nodeTitleRenderer: exampleNodeTitleRenderer
@@ -351,7 +360,7 @@ describe('<LayerTree />', () => {
         source: new OlSourceTileWMS()
       });
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
 
       layerGroup.getLayers().push(layer);
       expect(rebuildSpy).toHaveBeenCalled();
@@ -371,8 +380,8 @@ describe('<LayerTree />', () => {
         layers: [layer]
       });
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
-      const registerSpy = jest.spyOn(wrapper.instance(), 'registerAddRemoveListeners');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
+      const registerSpy = jest.spyOn((wrapper.instance() as LayerTree), 'registerAddRemoveListeners');
 
       layerGroup.getLayers().push(group);
       expect(rebuildSpy).toHaveBeenCalled();
@@ -388,8 +397,8 @@ describe('<LayerTree />', () => {
         map
       };
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
-      const unregisterSpy = jest.spyOn(wrapper.instance(), 'unregisterEventsByLayer');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
+      const unregisterSpy = jest.spyOn((wrapper.instance() as LayerTree), 'unregisterEventsByLayer');
 
       layerGroup.getLayers().remove(layer1);
       expect(rebuildSpy).toHaveBeenCalled();
@@ -411,14 +420,16 @@ describe('<LayerTree />', () => {
         source: new OlSourceTileWMS()
       });
       const nestedLayerGroup = new OlLayerGroup({
-        name: 'nestedLayerGroup',
+        properties: {
+          name: 'nestedLayerGroup'
+        },
         layers: [subLayer1, subLayer2]
       });
       layerGroup.getLayers().push(nestedLayerGroup);
 
       const wrapper = TestUtil.mountComponent(LayerTree, props);
-      const rebuildSpy = jest.spyOn(wrapper.instance(), 'rebuildTreeNodes');
-      const unregisterSpy = jest.spyOn(wrapper.instance(), 'unregisterEventsByLayer');
+      const rebuildSpy = jest.spyOn((wrapper.instance() as LayerTree), 'rebuildTreeNodes');
+      const unregisterSpy = jest.spyOn((wrapper.instance() as LayerTree), 'unregisterEventsByLayer');
 
       layerGroup.getLayers().remove(nestedLayerGroup);
       expect(rebuildSpy).toHaveBeenCalledTimes(1);
@@ -442,18 +453,21 @@ describe('<LayerTree />', () => {
           source: new OlSourceTileWMS()
         });
         const nestedLayerGroup = new OlLayerGroup({
-          name: 'nestedLayerGroup',
+          properties: {
+            name: 'nestedLayerGroup'
+          },
           layers: [subLayer1, subLayer2]
         });
         layerGroup.getLayers().push(nestedLayerGroup);
 
         const wrapper = TestUtil.mountComponent(LayerTree, props);
-        const oldOlListenerKey = wrapper.instance().olListenerKeys;
+        const oldOlListenerKey = (wrapper.instance() as LayerTree).olListenerKeys;
+        // @ts-ignore
         OlObservable.unByKey = jest.fn();
 
-        wrapper.instance().unregisterEventsByLayer(subLayer1);
+        (wrapper.instance() as LayerTree).unregisterEventsByLayer(subLayer1);
 
-        const newOlListenerKey = wrapper.instance().olListenerKeys;
+        const newOlListenerKey = (wrapper.instance() as LayerTree).olListenerKeys;
 
         expect(OlObservable.unByKey).toHaveBeenCalled();
         expect(newOlListenerKey.length).toBe(oldOlListenerKey.length - 1);
@@ -471,18 +485,21 @@ describe('<LayerTree />', () => {
           source: new OlSourceTileWMS()
         });
         const nestedLayerGroup = new OlLayerGroup({
-          name: 'nestedLayerGroup',
+          properties: {
+            name: 'nestedLayerGroup'
+          },
           layers: [subLayer1, subLayer2]
         });
         layerGroup.getLayers().push(nestedLayerGroup);
 
         const wrapper = TestUtil.mountComponent(LayerTree, props);
-        const oldOlListenerKey = wrapper.instance().olListenerKeys;
+        const oldOlListenerKey = (wrapper.instance() as LayerTree).olListenerKeys;
+        // @ts-ignore
         OlObservable.unByKey = jest.fn();
 
-        wrapper.instance().unregisterEventsByLayer(nestedLayerGroup);
+        (wrapper.instance() as LayerTree).unregisterEventsByLayer(nestedLayerGroup);
 
-        const newOlListenerKey = wrapper.instance().olListenerKeys;
+        const newOlListenerKey = (wrapper.instance() as LayerTree).olListenerKeys;
 
         expect(OlObservable.unByKey).toHaveBeenCalledTimes(2);
         expect(newOlListenerKey.length).toBe(oldOlListenerKey.length - 2);
@@ -501,9 +518,9 @@ describe('<LayerTree />', () => {
       const wrapper = TestUtil.mountComponent(LayerTree, props);
       layer1.setVisible(true);
 
-      wrapper.instance().setLayerVisibility(layer1, false);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layer1, false);
       expect(layer1.getVisible()).toBe(false);
-      wrapper.instance().setLayerVisibility(layer1, true);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layer1, true);
       expect(layer1.getVisible()).toBe(true);
     });
 
@@ -516,12 +533,12 @@ describe('<LayerTree />', () => {
       layer1.setVisible(true);
       layer2.setVisible(true);
 
-      wrapper.instance().setLayerVisibility(layerGroup, false);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layerGroup, false);
       expect(layerGroup.getVisible()).toBe(false);
       expect(layer1.getVisible()).toBe(false);
       expect(layer2.getVisible()).toBe(false);
 
-      wrapper.instance().setLayerVisibility(layerGroup, true);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layerGroup, true);
       expect(layerGroup.getVisible()).toBe(true);
       expect(layer1.getVisible()).toBe(true);
       expect(layer2.getVisible()).toBe(true);
@@ -540,14 +557,14 @@ describe('<LayerTree />', () => {
       layer3.setVisible(false);
 
 
-      wrapper.instance().setLayerVisibility(layer2, true);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layer2, true);
       expect(layerGroup.getVisible()).toBe(true);
       expect(layer1.getVisible()).toBe(false);
       expect(layer2.getVisible()).toBe(true);
       expect(layer3.getVisible()).toBe(false);
       expect(layerSubGroup.getVisible()).toBe(false);
 
-      wrapper.instance().setLayerVisibility(layer1, true);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layer1, true);
       expect(layerGroup.getVisible()).toBe(true);
       expect(layer1.getVisible()).toBe(true);
       expect(layer2.getVisible()).toBe(true);
@@ -560,7 +577,7 @@ describe('<LayerTree />', () => {
       layer2.setVisible(false);
       layer3.setVisible(false);
 
-      wrapper.instance().setLayerVisibility(layer3, true);
+      (wrapper.instance() as LayerTree).setLayerVisibility(layer3, true);
       expect(layer1.getVisible()).toBe(false);
       expect(layer2.getVisible()).toBe(false);
       expect(layer3.getVisible()).toBe(true);
diff --git a/src/LayerTree/LayerTree.tsx b/src/LayerTree/LayerTree.tsx
index 9947ba5fe6..8d865e8d55 100644
--- a/src/LayerTree/LayerTree.tsx
+++ b/src/LayerTree/LayerTree.tsx
@@ -18,6 +18,7 @@ import OlCollection from 'ol/Collection';
 import OlMapEvent from 'ol/MapEvent';
 import { unByKey } from 'ol/Observable';
 import { getUid } from 'ol';
+import { EventsKey as OlEventsKey } from 'ol/events';
 
 import _isFunction from 'lodash/isFunction';
 import _isEqual from 'lodash/isEqual';
@@ -27,7 +28,6 @@ import MapUtil from '@terrestris/ol-util/dist/MapUtil/MapUtil';
 import LayerTreeNode, { LayerTreeNodeProps } from './LayerTreeNode/LayerTreeNode';
 
 import { CSS_PREFIX } from '../constants';
-import { EventsKey } from 'ol/events';
 
 
 interface OwnProps {
@@ -101,7 +101,7 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
    *  An array of ol.EventsKey as returned by on() or once().
    * @private
    */
-  olListenerKeys: EventsKey[] = [];
+  olListenerKeys: OlEventsKey[] = [];
 
   /**
    * Create the LayerTree.
@@ -267,7 +267,7 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
   onCollectionRemove = (evt: any) => {
     this.unregisterEventsByLayer(evt.element);
     if (evt.element instanceof OlLayerGroup) {
-      evt.element.getLayers().forEach((layer) => {
+      evt.element.getLayers().forEach((layer: OlLayerBase) => {
         this.unregisterEventsByLayer(layer);
       });
     }
@@ -283,7 +283,7 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
   onChangeLayers = (evt: any) => {
     this.unregisterEventsByLayer(evt.oldValue);
     if (evt.oldValue instanceof OlCollection) {
-      evt.oldValue.forEach((layer) => this.unregisterEventsByLayer(layer));
+      evt.oldValue.forEach((layer: OlLayerBase) => this.unregisterEventsByLayer(layer));
     }
     if (evt.target instanceof OlLayerGroup) {
       this.registerAddRemoveListeners(evt.target);
@@ -381,7 +381,7 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
         return this.treeNodeFromLayer(childLayer);
       }).reverse();
     } else {
-      if (!this.hasListener(layer, 'change:visible', this.onLayerChangeVisible)) {
+      if (!this.hasListener({ target: layer, type: 'change:visible', listener: this.onLayerChangeVisible })) {
         const eventKey = layer.on('change:visible', this.onLayerChangeVisible);
         this.olListenerKeys.push(eventKey);
       }
@@ -401,24 +401,17 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
   /**
    * Determines if the target has already registered the given listener for the
    * given eventtype.
-   *
-   * @param target The event target.
-   * @param type The events type (name).
-   * @param listener The function.
-   * @return True if the listener is already contained in this.olListenerKeys.
    */
-  hasListener = (target, type, listener) => {
+  hasListener = (key: OlEventsKey) => {
     return this.olListenerKeys.some((listenerKey) => {
-      return listenerKey.target === target
-        && listenerKey.type === type
-        && listenerKey.listener === listener;
+      return listenerKey.target === key.target
+        && listenerKey.type === key.type
+        && listenerKey.listener === key.listener;
     });
   };
 
   /**
    * Reacts to the layer change:visible event and calls setCheckedState.
-   *
-   * @param evt The change:visible event
    */
   onLayerChangeVisible = () => {
     const checkedKeys = this.getVisibleOlUids();
@@ -434,11 +427,16 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
    *
    * @return The visible ol_uids.
    */
-  getVisibleOlUids = () => {
-    const layers = MapUtil.getAllLayers(this.state.layerGroup, (layer) => {
-      return !(layer instanceof OlLayerGroup) && layer.getVisible();
-    }).filter(this.props.filterFunction);
-    return layers.map(getUid);
+  getVisibleOlUids = (): string[] => {
+    if (!this.state.layerGroup) {
+      return [];
+    }
+
+    return MapUtil.getAllLayers(this.state.layerGroup, (layer: OlLayerBase) => {
+        return !(layer instanceof OlLayerGroup) && layer.getVisible();
+      })
+      .filter(this.props.filterFunction)
+      .map(getUid);
   };
 
   /**
@@ -450,9 +448,10 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
   onCheck(checkedKeys: string[], e: AntTreeNodeCheckedEvent) {
     const { checked = false } = e;
     const eventKey = e.node.props.eventKey;
-    const layer = MapUtil.getLayerByOlUid(this.props.map, eventKey);
-
-    this.setLayerVisibility(layer, checked);
+    if (eventKey) {
+      const layer = MapUtil.getLayerByOlUid(this.props.map, eventKey);
+      this.setLayerVisibility(layer, checked);
+    }
   }
 
   /**
@@ -508,6 +507,9 @@ class LayerTree extends React.Component<LayerTreeProps, LayerTreeState> {
    * @param e The ant-tree event object for this event. See ant docs.
    */
   onDrop(e: AntTreeNodeDropEvent) {
+    if (!e.dragNode.props.eventKey || !e.node.props.eventKey) {
+      return;
+    }
     const dragLayer = MapUtil.getLayerByOlUid(this.props.map, e.dragNode.props.eventKey);
     const dragInfo = MapUtil.getLayerPositionInfo(dragLayer, this.props.map);
     const dragCollection = dragInfo.groupLayer.getLayers();
diff --git a/src/Legend/Legend.tsx b/src/Legend/Legend.tsx
index 26cfafa9dd..d36481e0e0 100644
--- a/src/Legend/Legend.tsx
+++ b/src/Legend/Legend.tsx
@@ -25,7 +25,7 @@ export interface BaseProps {
   /**
    * Optional method that should be called when the image retrieval errors
    */
-  onError?: () => void;
+  onError?: (e: Error) => void;
   /**
    * Optional error message that should be displayed when image retrieval
    * errors. Will remove the browsers default broken image
@@ -120,7 +120,7 @@ export class Legend extends React.Component<LegendProps, LegendState> {
   /**
    * onError handler for the rendered img.
    */
-  onError(e) {
+  onError(e: Error) {
     Logger.warn(`Image error for legend of "${this.props.layer.get('name')}".`);
     this.setState({
       legendError: true
diff --git a/src/Panel/TimeLayerSliderPanel/TimeLayerSliderPanel.tsx b/src/Panel/TimeLayerSliderPanel/TimeLayerSliderPanel.tsx
index 71010d0842..980f9031b3 100644
--- a/src/Panel/TimeLayerSliderPanel/TimeLayerSliderPanel.tsx
+++ b/src/Panel/TimeLayerSliderPanel/TimeLayerSliderPanel.tsx
@@ -172,10 +172,8 @@ export class TimeLayerSliderPanel extends React.Component<TimeLayerSliderPanelPr
     if (!(_isEqual(nextProps.timeAwareLayers, timeAwareLayers))) {
       return true;
     }
-    if (!(_isEqual(nextProps.tooltips, tooltips))) {
-      return true;
-    }
-    return false;
+
+    return !(_isEqual(nextProps.tooltips, tooltips));
   }
 
   /**
@@ -331,15 +329,9 @@ export class TimeLayerSliderPanel extends React.Component<TimeLayerSliderPanelPr
   /**
    * handle playback speed change
    */
-  onPlaybackSpeedChange = (val: string) => {
-    let valueToSet;
-    if (_isFinite(parseFloat(val))) {
-      valueToSet = parseFloat(val);
-    } else {
-      valueToSet = val;
-    }
+  onPlaybackSpeedChange = (val: number | PlaybackSpeedType) => {
     this.setState({
-      playbackSpeed: valueToSet
+      playbackSpeed: val
     }, () => {
       if (this.state.autoPlayActive) {
         this.autoPlay(true);
@@ -487,7 +479,7 @@ export class TimeLayerSliderPanel extends React.Component<TimeLayerSliderPanelPr
           pressedIconName="pause-circle"
         />
         <Select
-          defaultValue={'1'}
+          defaultValue={1}
           className={extraCls + ' speed-picker'}
           onChange={this.onPlaybackSpeedChange}
         >
diff --git a/src/Slider/LayerTransparencySlider/LayerTransparencySlider.tsx b/src/Slider/LayerTransparencySlider/LayerTransparencySlider.tsx
index d18095c5ad..602aa63d88 100644
--- a/src/Slider/LayerTransparencySlider/LayerTransparencySlider.tsx
+++ b/src/Slider/LayerTransparencySlider/LayerTransparencySlider.tsx
@@ -66,8 +66,8 @@ class LayerTransparencySlider extends React.Component<LayerTransparencySliderPro
       <Slider
         tipFormatter={value => `${value}%`}
         defaultValue={this.getLayerTransparency()}
-        onChange={(value) => {
-          this.setLayerTransparency(value as number);
+        onChange={(value: number) => {
+          this.setLayerTransparency(value);
         }}
         {...passThroughProps}
       />
diff --git a/src/Slider/TimeSlider/TimeSlider.spec.tsx b/src/Slider/TimeSlider/TimeSlider.spec.tsx
index 2b8b5ef7ca..e8ca66e38b 100644
--- a/src/Slider/TimeSlider/TimeSlider.spec.tsx
+++ b/src/Slider/TimeSlider/TimeSlider.spec.tsx
@@ -12,12 +12,6 @@ describe('<TimeSlider />', () => {
     expect(wrapper).not.toBeUndefined();
   });
 
-  it('does not fail to convert on undefined', () => {
-    const slider = TestUtil.mountComponent(TimeSlider, {}).instance();
-    const undef = slider.convert();
-    expect(undef).toBeUndefined();
-  });
-
   it('converts time millis properly', () => {
     const slider = TestUtil.mountComponent(TimeSlider, {}).instance();
     const time = moment(1500000000000);
diff --git a/src/Slider/TimeSlider/TimeSlider.tsx b/src/Slider/TimeSlider/TimeSlider.tsx
index 25bfae761a..20062ba3ba 100644
--- a/src/Slider/TimeSlider/TimeSlider.tsx
+++ b/src/Slider/TimeSlider/TimeSlider.tsx
@@ -105,10 +105,7 @@ class TimeSlider extends React.Component<TimeSliderProps> {
    * @param val the input value(s)
    * @return The converted value(s)
    */
-  convert(val: string[] | string): number | [number, number] | undefined {
-    if (val === undefined) {
-      return val as undefined;
-    }
+  convert(val: string[] | string): number | [number, number] {
     return _isArray(val) ?
       (val as Array<string>).map(iso => moment(iso).unix()) as [number, number]:
       moment(val).unix() as number;
@@ -136,8 +133,8 @@ class TimeSlider extends React.Component<TimeSliderProps> {
    * @param unix unix timestamps
    * @return The formatted timestamps
    */
-  formatTimestamp(unix: number): string {
-    return moment(unix * 1000).format(this.props.formatString);
+  formatTimestamp(unix: number|undefined): string {
+    return unix ? moment(unix * 1000).format(this.props.formatString) : '';
   }
 
   /**
@@ -175,30 +172,37 @@ class TimeSlider extends React.Component<TimeSliderProps> {
 
     const convertedMarks = this.convertMarks(marks);
 
-    let defaultVal;
-    let val;
     if (useRange) {
-      defaultVal = this.convert(defaultValue) as [number, number];
-      val = this.convert(value) as [number, number];
+      return (
+        <Slider
+          className={finalClassName}
+          defaultValue={this.convert(defaultValue) as [number, number]}
+          range={true}
+          min={moment(min).unix()}
+          max={moment(max).unix()}
+          tipFormatter={val => this.formatTimestamp(val)}
+          onChange={val => this.valueUpdated(val)}
+          value={this.convert(value) as [number, number]}
+          marks={convertedMarks}
+          {...passThroughProps}
+        />
+      );
     } else {
-      defaultVal = this.convert(defaultValue) as number;
-      val = this.convert(value) as number;
+      return (
+        <Slider
+          className={finalClassName}
+          defaultValue={this.convert(defaultValue) as number}
+          range={false}
+          min={moment(min).unix()}
+          max={moment(max).unix()}
+          tipFormatter={val => this.formatTimestamp(val)}
+          onChange={val => this.valueUpdated(val)}
+          value={this.convert(value) as number}
+          marks={convertedMarks}
+          {...passThroughProps}
+        />
+      );
     }
-
-    return (
-      <Slider
-        className={finalClassName}
-        defaultValue={defaultVal}
-        range={useRange}
-        min={moment(min).unix()}
-        max={moment(max).unix()}
-        tipFormatter={this.formatTimestamp.bind(this)}
-        onChange={this.valueUpdated.bind(this)}
-        value={val}
-        marks={convertedMarks}
-        {...passThroughProps}
-      />
-    );
   }
 }
 
diff --git a/tsconfig.json b/tsconfig.json
index 93232352de..c63767cddc 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -10,7 +10,7 @@
     "lib": ["es7", "dom"],
     "module": "commonjs",
     "moduleResolution": "node",
-    "noImplicitAny": false, //temporal
+    "noImplicitAny": true,
     "noImplicitReturns": true,
     "noImplicitThis": true,
     "noUnusedLocals": true,