Viewshed #2917
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Viewshed #2917
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added 2 commits
May 7, 2019 19:11
Allow non-local illumination to compensate for the fact that the union of the pixels in the rays is not guranteed to completely cover the entire tile (especially far from the source at severe angels).
pomadchin
reviewed
May 7, 2019
| @@ -90,8 +90,12 @@ object R2Viewshed extends Serializable { | |||
| * @param cols The number of columns | |||
| * @param rows The number of rows | |||
| */ | |||
| def generateEmptyViewshedTile(cols: Int, rows: Int) = | |||
| ArrayTile.empty(IntConstantNoDataCellType, cols, rows) | |||
| def generateEmptyViewshedTile(cols: Int, rows: Int, debug: Int = 0) = { | |||
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It looks like debug should be Boolean here, if you still want to keep this flag. (sorry that it's a bit early comment since your pr is in progress :))
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That is an integer because it allows one to generate tiles with different "background colors" for debugging purposes. For example, setting debug = key.col + 101*key.row in IterativeViewshed allows one confirm in QGIS which spatial key each tile comes from. It is the visual equivalent of a printf.
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@jamesmcclain thanks for clarifying 👍
pomadchin
approved these changes
May 8, 2019
docs/CHANGELOG.rst
Outdated
| @@ -1,6 +1,14 @@ | |||
| Changelog | |||
| ========= | |||
|
|
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| 3.0.1-SNAPSHOT | |||
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Can you move your update into 3.0.0-SNAPSHOT section, please?
|
Thanks, James! |
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Overview
The issue is that some fidelity is lost when visibility information is transferred between adjacent tiles. The reconstituted data, a collection of line segments associated with each tile, is not guaranteed to cover every pixel in the tile. The solution presented here is to optionally allow light to scatter perpendicularly from each ray.
There have been no changes made to the unit tests because it is unclear how to test a fix like this. Suggestions welcome.Can be tested with https://github.com/jamesmcclain/ViewshedDebug (locally-publish this branch then type./sbt "project vs" assembly, then$SPARK_HOME/bin/spark-submit --driver-memory=8G --master='local[*]' vs-assembly-0.jar).Artifacts
Before:
After:
Meters per Pixel
Before:
After:
Comparison:
Checklist
docs/CHANGELOG.rstupdated, if necessarydocsguides update, if necessaryDemo
Optional. Screenshots/REPL
Notes
Optional. Ancillary topics, caveats, alternative strategies that didn't work out, anything else.
Closes #2910