Kontinuation commented on code in PR #594:
URL: https://github.com/apache/sedona-db/pull/594#discussion_r2788772655
##########
rust/sedona-raster-functions/src/rs_envelope.rs:
##########
@@ -94,25 +94,37 @@ impl SedonaScalarKernel for RsEnvelope {
}
}
-/// Create WKB for a polygon for the raster
+/// Create WKB for the axis-aligned bounding box (envelope) of the raster.
+///
+/// This computes the four corners of the raster in world coordinates, then
+/// derives the min/max X and Y to produce an axis-aligned bounding box.
+/// For skewed/rotated rasters, this differs from the convex hull.
fn create_envelope_wkb(raster: &dyn RasterRef, out: &mut impl std::io::Write)
-> Result<()> {
- // Compute the four corners of the raster in world coordinates.
- // Due to skew/rotation in the affine transformation, each corner must be
- // computed individually.
-
let width = raster.metadata().width() as i64;
let height = raster.metadata().height() as i64;
- // Compute the four corners in pixel coordinates:
- // Upper-left (0, 0), Upper-right (width, 0), Lower-right (width, height),
Lower-left (0, height)
+ // Compute the four corners in world coordinates
let (ulx, uly) = to_world_coordinate(raster, 0, 0);
let (urx, ury) = to_world_coordinate(raster, width, 0);
let (lrx, lry) = to_world_coordinate(raster, width, height);
let (llx, lly) = to_world_coordinate(raster, 0, height);
+ // Compute the axis-aligned bounding box
+ let min_x = ulx.min(urx).min(lrx).min(llx);
+ let max_x = ulx.max(urx).max(lrx).max(llx);
+ let min_y = uly.min(ury).min(lry).min(lly);
+ let max_y = uly.max(ury).max(lry).max(lly);
+
write_wkb_polygon(
out,
- [(ulx, uly), (urx, ury), (lrx, lry), (llx, lly), (ulx,
uly)].into_iter(),
+ [
+ (min_x, max_y),
+ (max_x, max_y),
+ (max_x, min_y),
+ (min_x, min_y),
+ (min_x, max_y),
Review Comment:
Fixed coordinate order and tests
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