Terrain and land cover of one upazila. Part of what the twin can answer. Every figure below is the value the route serves, with its source; the raw response is at /api/twin/brain/terrain/BD40470064.
Not validated
Basis: computed from raster (NOT-VALIDATED): exact arithmetic over sha256-pinned stored tiles (pixel-centre ownership, histogram percentiles, approximate pixel areas); no validation gate.
The upazila's own zonal statistics, unmodified, plus its rank on four headline measures; every figure is exact arithmetic over the sha256-pinned stored pixels.
| Measure | Rank | Of | Value |
|---|---|---|---|
| Mean elevation, 1 is the lowest of the 507 | Rank: 5 | Of: 507 | Value: 2.02 |
| Share of DEM pixels below 5 m, 1 is the highest |
| Class | Share of pixels | Pixels | Approximate area |
|---|---|---|---|
| Permanent water bodies | Share of pixels: 48.9% | Pixels: 2,339,485 | Approximate area: 185 km² |
| Source | Published by | What it is | Caveat |
|---|---|---|---|
| Copernicus DEM GLO-30 tiles, stored copy | Published by: Copernicus DEM (ESA/Copernicus); stored at copernicus-dem-glo30-bd | What it is: 30 m elevation pixels, EPSG:4326, float32, nodata None; 31 tiles covering all 507 upazila polygons | Caveat: The stored tiles carry no version tag or licence file, so source_version says so. Percentiles come from a fixed histogram (0.5 m bins below 32 m, 4 m bins to 1280 m); the below-5 m and below-10 m shares are exact pixel counts. Coastal polygons include sea and river pixels, and a GLO-30 water surface reads near 0 m, so 'below 5 m' is a share of raster pixels inside the polygon, not of land. |
source_version carries 'not stated in the stored files' rather than a version guessed from the name.| Of: 507 |
| Value: 90.56 |
| Built-up share, 1 is the highest | Rank: 359 | Of: 507 | Value: 0.51 |
| Cropland share, 1 is the highest | Rank: 431 | Of: 507 | Value: 29.35 |
| Share of pixels: 29.35% |
| Pixels: 1,404,298 |
| Approximate area: 111.05 km² |
| Tree cover | Share of pixels: 17.07% | Pixels: 816,461 | Approximate area: 64.56 km² |
| Bare/sparse vegetation | Share of pixels: 2.32% | Pixels: 111,213 | Approximate area: 8.79 km² |
| Grassland | Share of pixels: 1.6% | Pixels: 76,613 | Approximate area: 6.06 km² |
| Built-up | Share of pixels: 0.51% | Pixels: 24,364 | Approximate area: 1.93 km² |
| Herbaceous wetland | Share of pixels: 0.23% | Pixels: 11,181 | Approximate area: 0.88 km² |
| Mangroves | Share of pixels: 0.02% | Pixels: 732 | Approximate area: 0.06 km² |
| ESA WorldCover v200 (epoch 2021) tiles, stored copy | Published by: ESA WorldCover project 2021 (algorithm_version tag V2.0.0); stored at esa-worldcover-bd | What it is: 10 m class pixels, EPSG:4326, uint8, nodata 0; 6 tiles covering all 507 upazila polygons; class labels and the CC-BY 4.0 licence are read from the tiles' own metadata tags | Caveat: Class shares are pixel-count shares of the upazila's valid pixels (a row sums to 100 by construction); per-class areas use the latitude-corrected pixel size at the upazila centroid and are approximate. The epoch is 2021, one snapshot, not a time series. |
| OCHA COD-AB v03 admin3 (upazila) polygons, the layer bulkbd used | Published by: OCHA Common Operational Datasets; stored at bgd_admin3 | What it is: 507 polygons keyed by adm3_pcode; a pixel belongs to the upazila whose polygon contains the pixel centre (all_touched=False, polygons verified non-overlapping) | Caveat: Twin place links are the D1 crosswalk bbs_geocode adm3 rows: 468 of the 507 upazilas carry a portal_id; the other 39 serve null portal_id, never a guess. |