Agent Guidance, Sample Raster COG

A reference COG for exercising raster tooling, Landsat-derived RGB over Andros Island in the Bahamas. Nothing here supports analysis, the value is mechanical, a small well-formed COG with verified statistics.

Read the COG data asset with rioxarray.open_rasterio("sample-cog.tif", masked=True) or rasterio. It serves windowed reads and overviews over HTTP range requests, so read the window you need rather than the whole file. For a quick preview use the thumbnail asset.

Quirks

• Nodata is 0 and about 33 percent of pixels are the rotated-scene collar. Valid data starts at 1, so always read with masking on, treating 0 as a measurement skews every statistic.
• There is no acquisition timestamp anywhere. The collection temporal start is the Landsat 7 launch date, a bound, not a date.
• Eastings run 101,985 to 339,315 meters, far west of the UTM zone 18 central meridian. Legal values, they just look odd.

Coordinate Reference System

EPSG:32618, WGS 84 / UTM zone 18N, a projected coordinate reference system whose coordinates are in metres. Pixel size is in metres, so cell size and any distance read off the grid are already in metres. Web maps need a warp to EPSG:3857, and joining to data in degrees needs EPSG:4326 first. The data asset carries the same code as proj:code.

Pixel Math

Pixels are 300.04 meters square, so one pixel is about 9 hectares and pixel counts convert to area by multiplying by 300.04 squared.

Tested Reads

Windowed read and an overview read with rasterio.

Masked statistics with rioxarray.

Related Collections

None. This is the catalog's only raster and joins to nothing. The upstream fixture is tagged on the source asset with its checksum, and band statistics live in the STAC bands metadata and as GDAL STATISTICS_* tags in the file header, written by the same build.