portolan-pipeline
A small 3-band Cloud Optimized GeoTIFF used to exercise the raster path end to end, rasterio's RGB.byte.tif test fixture, derived from USGS Landsat 7 imagery over Andros Island in the Bahamas. Optimized to a COG with per-band statistics, minimum, maximum, mean, and standard deviation, embedded in the header, in UTM zone 18N (EPSG:32618).
A 791 by 718 pixel, 3-band, 8-bit image at roughly 300 meter resolution whose georeferencing places it over Andros Island in the Bahamas, the shallow Great Bahama Bank to its west and the deep Tongue of the Ocean along its east coast. It is rasterio's RGB.byte.tif test fixture, derived from USGS Landsat 7 imagery per the project's test data notes, in the repository since rasterio's first tests in November 2013 and the workhorse image of its README and topic guides ever since. Anyone who has learned rasterio has seen this picture.
Here it exercises the Portolan raster path end to end, a Cloud Optimized GeoTIFF with internal tiling, an overview level, and per-band statistics embedded in both the STAC metadata and the GeoTIFF header.
Agents, AGENTS.md covers the nodata trap and windowed reads.
The data asset is a Cloud Optimized GeoTIFF, so the same call against the published URL streams only the bytes it needs over HTTP range requests. Pass masked=True so nodata reads as NaN.
A Cloud Optimized GeoTIFF serves partial reads over HTTP. Opening the published copy with GDAL's debug output on shows it, a 64 pixel window costs two range requests of roughly 0.4 MB, not the whole file.
Learning and testing COG access patterns, windowed reads, overview reads, HTTP range requests, at a size where experiments cost nothing. Its familiarity is the feature, tutorials and bug reports written against rasterio's docs transfer directly.
Not an analytically useful dataset, and the documentation should be the last place you learn that. The acquisition date and Landsat scene id are unrecorded, the temporal extent here starts at the Landsat 7 launch in April 1999 only as an honest lower bound. Bands are display-stretched 8-bit RGB, not calibrated reflectance, so no conclusion about the Bahamas should be drawn from these pixels. About a third of the image is a nodata collar from the rotated scene footprint.
License, CC0-1.0. Providers, rasterio (producer, licensor), Portolan SDI (host). Original source, https://raw.githubusercontent.com/rasterio/rasterio/main/tests/data/RGB.byte.tif . Bands, 3. CRS, EPSG:32618. Cloud-native asset, sample-cog.tif (COG).
