Geo
A tiled GeoTIFF opened for pyramid access: the resolution ladder (full-resolution image plus every overview IFD), the georeference, and the sampling used to resample an arbitrary geographic sector into one engine tile.
The file is never read whole. Opening parses tags only; each rendered tile picks the overview closest to its own resolution and decodes just the blocks it lands on, so a multi-gigabyte orthophoto costs the same per tile as a small one.
A file without overviews still works, but every zoomed-out tile has to decimate the full-resolution raster — the open call logs a warning suggesting gdaladdo / COG conversion, which is the fix.
Instances are safe to sample from multiple coroutines: sampling holds no shared mutable state (block caching is per call) and TiffDataSource implementations serialize reads.
Properties
Whether the file holds a picture or a height field, inferred from its tags, with the evidence attached. Resource managers filing an imported file under "maps" or "terrain" want this; see probeContent for the GeoTiffContent.AMBIGUOUS case.
Native resolution in degrees of latitude per pixel — the finest detail the file holds.
True unless the tags say the raster is a picture. Deliberately includes GeoTiffContent.AMBIGUOUS, so a caller that asked for terrain gets it; a caller deciding which category a file belongs to should read contentHint instead.
Resolution ladder, finest first: index 0 is the full-resolution raster.
Full-resolution raster.
Functions
Resolution of ladder entry index in degrees of latitude per pixel.
Settle GeoTiffContent.AMBIGUOUS from the pixels, returning contentHint unchanged for files the tags already decided.
Resample sector into a width × height grid of 0xAARRGGBB pixels. Pixels with no source coverage (outside the raster, nodata, or an undecodable block) are fully transparent, so a tile that only partly overlaps the image composites correctly over whatever is beneath it.
Resample sector into a width × height grid of 16-bit elevations, north-up and row-major with the engine's texel-centre convention. Missing posts — outside the raster, GDAL_NODATA, or an undecodable block — come back as Short.MIN_VALUE, which is the engine's own missing-data sentinel.
Index of the ladder entry to sample for a tile of degreesPerTexel resolution — the coarsest overview that still resolves the tile, so zoomed-out tiles read a small overview instead of decimating the full-resolution raster.