World coordinates #297
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World coordinates #297
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This will allows us to store coordinate data in an unscaled mercator (like Google Maps world coordinates) This will have several benefits: - it breaks the projection code up so that the expensive trig functions only need to happen once, and each projection can just be a translate/scale - we can store world coordinates for indexing, it should ease things like label placement, conflation
This has some benefits, but the main one is that it makes the transform from world -> screen easier (reprojections/pans/zooms should speed up with less division) It means we will need to change how Transform works, I'll do that next.
This makes things much simpler. Project/unproject can go through world coordinates and we can avoid doing math with extra Math.PI and division associated with the D3-like `scale`/`k` property.
This replaces "pxExtent" which was in a different kind of world coordinates with "tileExtent" which will be in the world coordinates used everywhere. The tiler behavior has changed slightly around non-256px tile sizes. Before we would calculate the tiles in these sizes, now we just adjust the zoom. I will test to see if this works as expected.
(re: #296) This also adds "@esbuild/darwin-arm64" optional dependency
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This introduces breaking changes to the Viewport (projection), Transform, and Tiler code to support "world coordinates".
(see Google Maps world coordinates)
I've been using it with my private fork of Rapid for several months and it's proven useful! We can now cache geometry in Mercator - this speeds up rendering and spatial testing for things like bounding boxes and conflation.
Viewportto do these conversions:wgs84ToWorld(lonlat) : xyworldToWgs84(xy): lonlatworldToScreen(xy): xyscreenToWorld(xy): xyproject(lonlat): xy=worldToScreen(wgs84ToWorld(lonlat))unproject(xy): lonlat=worldToWgs84(screenToWorld(xy))Transformcode to replace the oldkscale with a straightforwardzparameter.Math.PIbaked into it) and zoom (which is just an integer).geoZoomToScaleandgeoScaleToZoomfunctions are still there.This also fixes #296 along the way, reversing the winding of Extent.polygon() to be counterclockwise, as GeoJSON expects.