fix: break out projection wrapper into new component

include/geopackage/proj.hpp

@@ -0,0 +1,31 @@
+#ifndef NGEN_GEOPACKAGE_PROJ_HPP
+#define NGEN_GEOPACKAGE_PROJ_HPP
+
+#include <boost/geometry/srs/projection.hpp>
+
+namespace ngen {
+namespace srs {
+
+namespace bg = boost::geometry;
+
+struct epsg
+{
+    using srs_type = bg::srs::dpar::parameters<double>;
+
+    enum {
+        wgs84        = 4326,
+        conus_albers = 5070,
+        mercator     = 3857
+    };
+
+    static srs_type get(uint32_t srid);
+
+  private:
+    static const srs_type epsg5070_;
+    static const srs_type epsg3857_;
+};
+
+} // namespace srs
+} // namespace ngen
+
+#endif // NGEN_GEOPACKAGE_PROJ_HPP

include/geopackage/wkb.hpp

@@ -54,8 +54,6 @@ struct wkb {
      */
     static geometry read(const boost::span<const uint8_t> buffer);
 
-    static bg::srs::dpar::parameters<> get_prj(uint32_t srid);
-
   private:
     /**
      * Read a WKB point into a cartesian model.

src/geopackage/CMakeLists.txt

@@ -9,7 +9,8 @@ if (NOT _cmp)
     set_source_files_properties(wkb.cpp PROPERTIES COMPILE_OPTIONS "-O0;-fno-sanitize=all")
 endif()
 
-add_library(geopackage geometry.cpp
+add_library(geopackage proj.cpp
+                       geometry.cpp
                        properties.cpp
                        feature.cpp
                        read.cpp

src/geopackage/geometry.cpp

@@ -1,6 +1,7 @@
 #include "geopackage.hpp"
 #include "EndianCopy.hpp"
 #include "wkb.hpp"
+#include "proj.hpp"
 
 geojson::geometry ngen::geopackage::build_geometry(
     const ngen::sqlite::database::iterator& row,
@@ -26,8 +27,8 @@ geojson::geometry ngen::geopackage::build_geometry(
     uint32_t srs_id = 0;
     utils::copy_from(geometry_blob, index, srs_id, endian);
 
-    const auto epsg = wkb::get_prj(srs_id);
-    const bg::srs::transformation<> prj{epsg, wkb::get_prj(4326)};
+    const auto epsg = ngen::srs::epsg::get(srs_id);
+    const bg::srs::transformation<> prj{epsg, ngen::srs::epsg::get(ngen::srs::epsg::wgs84)};
     wkb::wgs84 pvisitor{srs_id, prj};
 
     if (indicator > 0 & indicator < 5) {
@@ -50,7 +51,7 @@ geojson::geometry ngen::geopackage::build_geometry(
         geojson::coordinate_t min_prj{};
 
         // project the raw bounding box
-        if (srs_id == 4326) {
+        if (srs_id == srs::epsg::wgs84) {
             max_prj = geojson::coordinate_t{max.get<0>(), max.get<1>()};
             min_prj = geojson::coordinate_t{min.get<0>(), min.get<1>()};
         } else {

src/geopackage/proj.cpp

@@ -0,0 +1,43 @@
+#include "proj.hpp"
+#include <boost/geometry/srs/projections/epsg.hpp>
+
+namespace ngen {
+namespace srs {
+
+const epsg::srs_type epsg::epsg5070_ =
+    epsg::srs_type(bg::srs::dpar::proj_aea)
+                  (bg::srs::dpar::ellps_grs80)
+                  (bg::srs::dpar::towgs84, {0,0,0,0,0,0,0})
+                  (bg::srs::dpar::lat_0, 23)
+                  (bg::srs::dpar::lon_0, -96)
+                  (bg::srs::dpar::lat_1, 29.5)
+                  (bg::srs::dpar::lat_2, 45.5)
+                  (bg::srs::dpar::x_0, 0)
+                  (bg::srs::dpar::y_0, 0);
+
+const epsg::srs_type epsg::epsg3857_ =
+    epsg::srs_type(bg::srs::dpar::proj_merc)
+                  (bg::srs::dpar::units_m)
+                  (bg::srs::dpar::no_defs)
+                  (bg::srs::dpar::a, 6378137)
+                  (bg::srs::dpar::b, 6378137)
+                  (bg::srs::dpar::lat_ts, 0)
+                  (bg::srs::dpar::lon_0, 0)
+                  (bg::srs::dpar::x_0, 0)
+                  (bg::srs::dpar::y_0, 0)
+                  (bg::srs::dpar::k, 1);
+
+auto epsg::get(uint32_t srid) -> srs_type
+{
+    switch (srid) {
+        case 5070:
+            return epsg5070_;
+        case 3857:
+            return epsg3857_;
+        default:
+            return bg::projections::detail::epsg_to_parameters(srid);
+    }
+}
+
+} // namespace srs
+} // namespace ngen

src/geopackage/wkb.cpp

@@ -1,4 +1,5 @@
 #include "wkb.hpp"
+#include "proj.hpp"
 
 namespace ngen {
 namespace geopackage {
@@ -197,51 +198,9 @@ typename wkb::geometry wkb::read(const boost::span<const uint8_t> buffer)
 // WKB Projection Visitor
 // ----------------------------------------------------------------------------
 
-bg::srs::dpar::parameters<> wkb::get_prj(uint32_t srid) {
-    /**
-     * EPSG 5070 and 3857 projection definitions for use with boost::geometry.
-     *
-     * @note these are required because boost 1.72.0 does not
-     *       have an EPSG definition for 5070 or 3857 in boost::srs::epsg.
-     */
-    const static auto epsg5070 = bg::srs::dpar::parameters<>
-        (bg::srs::dpar::proj_aea)
-        (bg::srs::dpar::ellps_grs80)
-        (bg::srs::dpar::towgs84, {0,0,0,0,0,0,0})
-        (bg::srs::dpar::lat_0, 23)
-        (bg::srs::dpar::lon_0, -96)
-        (bg::srs::dpar::lat_1, 29.5)
-        (bg::srs::dpar::lat_2, 45.5)
-        (bg::srs::dpar::x_0, 0)
-        (bg::srs::dpar::y_0, 0);
-
-    const static auto epsg3857 = bg::srs::dpar::parameters<>
-        (bg::srs::dpar::proj_merc)
-        (bg::srs::dpar::units_m)
-        (bg::srs::dpar::no_defs)
-        (bg::srs::dpar::a, 6378137)
-        (bg::srs::dpar::b, 6378137)
-        (bg::srs::dpar::lat_ts, 0)
-        (bg::srs::dpar::lon_0, 0)
-        (bg::srs::dpar::x_0, 0)
-        (bg::srs::dpar::y_0, 0)
-        (bg::srs::dpar::k, 1);
-
-    switch(srid) {
-        case 5070:
-            return epsg5070;
-        case 3857:
-            return epsg3857;
-        default:
-            return bg::projections::detail::epsg_to_parameters(srid);
-    }
-}
-
-// ----------------------------------------------------------------------------
-
 geojson::geometry wkb::wgs84::operator()(point_t& g)
 {
-    if (this->srs == 4326) {
+    if (this->srs == ngen::srs::epsg::wgs84) {
         return geojson::coordinate_t(g.get<0>(), g.get<1>());
     }
 
@@ -256,7 +215,7 @@ geojson::geometry wkb::wgs84::operator()(linestring_t& g)
 {
     geojson::linestring_t h;
 
-    if (this->srs == 4326) {
+    if (this->srs == ngen::srs::epsg::wgs84) {
         h.reserve(g.size());
         for (auto&& gg : g) {
             h.emplace_back(
@@ -276,7 +235,7 @@ geojson::geometry wkb::wgs84::operator()(polygon_t& g)
 {
     geojson::polygon_t h;
 
-    if(this->srs == 4326) {
+    if(this->srs == ngen::srs::epsg::wgs84) {
         h.outer().reserve(g.outer().size());
         for (auto&& gg : g.outer()) {
             h.outer().emplace_back(
@@ -309,7 +268,7 @@ geojson::geometry wkb::wgs84::operator()(multipoint_t& g)
 {
     geojson::multipoint_t h;
 
-    if (this->srs == 4326) {
+    if (this->srs == ngen::srs::epsg::wgs84) {
         h.reserve(g.size());
         for (auto&& gg : g) {
             h.emplace_back(
@@ -330,7 +289,7 @@ geojson::geometry wkb::wgs84::operator()(multilinestring_t& g)
 {
     geojson::multilinestring_t h;
 
-    if (this->srs == 4326) {
+    if (this->srs == ngen::srs::epsg::wgs84) {
         h.resize(g.size());
         auto&& line_g = g.begin();
         auto&& line_h = h.begin();
@@ -352,7 +311,7 @@ geojson::geometry wkb::wgs84::operator()(multipolygon_t& g)
 {
     geojson::multipolygon_t h;
 
-    if (this->srs == 4326) {
+    if (this->srs == ngen::srs::epsg::wgs84) {
         h.resize(g.size());
         auto&& polygon_g = g.begin();
         auto&& polygon_h = h.begin();