Read README.md first. It is the canonical description of this dataset, and the source repository serves the same text. This document adds what that prose leaves out.
The lst-p95-2021-2025 collection has one item per tile of the degree grid, 769 of them. Each item carries two Cloud Optimized GeoTIFFs. N15E025 is one tile. A tile takes its name from its north and west edges. S30W065 starts at 30 S, 65 W.
Read a window rather than the whole file. The internal tiles measure 512 by 512 pixels. The overviews store a reduced copy for a whole-tile draw.
DN 0 is nodata. Treat it as absent rather than cold.
The raster separates none of these meanings:
Read qa_count beside the pixel, as evidence rather than as an answer. A count above 0 narrows the pixel to the last two rows, and the count itself stands. 1 to 4 is the evidence rule. 5 or more is a temperature bound. A count of 0 covers the other four rows together, and nothing in the raster tells them apart.
Both water rules zero the count with the temperature. Neither a source fill nor a rejected observation increments it. A zero count is no signature of sea, and a nodata pixel is no cloudy one. Each item's processing:lineage states every rule, and references by checksum the artifacts each rule reads.
Shape is the one clue the raster does offer. A straight-edged region of zeros is ground outside Landsat's imaged footprint. The scene rectangles that cover it describe files rather than ground.
qa_count has 12 bands, January through December. Band m counts the clear observations that entered the percentile for that calendar month, pooled across every year in the window. The count saturates at 255. A zero is a real count rather than a gap, and the band declares no nodata value.
Check each item's processing:lineage first. A tile built with the WRS seam correction carries a percentile taken against each scene's own calendar-month median. An uncorrected tile carries the hottest observed value. Both rasters look alike, and the numbers answer different questions. A difference between tiles built under different rules measures the rule rather than the ground. The lineage records which rule ran and which scenes fitted the offsets.
Read items.parquet. It gives every item's metadata in one range request. The alternative is one fetch per item, 769 of them.