| --- |
| license: other |
| task_categories: |
| - other |
| tags: |
| - elevation |
| - srtm |
| - geotiff |
| - dem |
| - terrain |
| size_categories: |
| - extra-extra-large-1M+ |
| --- |
| |
| # SRTM 30m Global Digital Elevation Model |
|
|
| NASA Shuttle Radar Topography Mission (SRTM) 30m resolution global DEM, converted to Cloud Optimized GeoTIFF format. |
|
|
| ## Dataset Details |
|
|
| - **Source:** NASA SRTM GL1 v3 (Global 1 arc-second, ~30m resolution) |
| - **Coverage:** 80% of land surface between 56°S and 60°N |
| - **Resolution:** ~30 meters (1 arc-second) |
| - **Format:** GeoTIFF with Deflate compression, 16-bit signed integer |
| - **Files:** 14,296 tiles, ~65 GB total |
| - **Tile naming:** `N{lat}E{lon}.tif` or `S{lat}W{lon}.tif` (1°×1° tiles) |
| - **Internal tiling:** 256×256 pixels, 15×15 grid per file (225 internal tiles) |
| - **NoData value:** -32768 |
| - **Horizontal datum:** WGS 84 |
|
|
| ## Usage |
|
|
| ### Via OpenZenith API |
|
|
| ``` |
| GET https://openzenith.pages.dev/api/elevation?lat=28.5&lon=96.5 |
| ``` |
|
|
| ### Direct download |
|
|
| ```python |
| from huggingface_hub import hf_hub_download |
| path = hf_hub_download("aliasfox/srtm30m", "N28E096.tif", repo_type="dataset") |
| ``` |
|
|
| ### HTTP Range requests |
|
|
| Each GeoTIFF file supports HTTP Range requests. The first ~4KB contains the IFD (Image File Directory) with tile offsets. Each 256×256 internal tile can be fetched individually (~3-53 KB compressed). |
|
|
| ## File Structure |
|
|
| Each file covers a 1°×1° area: |
| - Image size: 3601×3601 pixels |
| - Pixel values: elevation in meters (Int16) |
| - Compression: Deflate (zlib) |
| - Internal tiles: 256×256 (225 tiles per file) |
|
|
