---
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)