Everything starts with elevation. The SRTM (Shuttle Radar Topography Mission) provides 1-arc-second (~30 m) digital elevation models covering the entire Parvati Valley and surrounding ranges. These are the raw material from which terrain meshes, hillshades, and satellite-textured landscapes are built.

Data Source

SRTM tiles from AWS Mapzen elevation tiles (public, no authentication):

  • N31E077 and N32E077 — two tiles covering the Parvati Valley extent
  • 3601 × 3601 pixels per tile, signed 16-bit big-endian
  • ~30 m horizontal resolution, ~1 m vertical accuracy

Processing Pipeline

  1. Download — fetch .hgt.gz tiles from S3
  2. Parse — load as NumPy float32, handle voids (NaN)
  3. Stitch — combine adjacent tiles into continuous elevation grids
  4. Subsample — reduce resolution for mesh generation (step=3 to step=8)
  5. Hillshade — compute synthetic illumination for 2D visualisation
  6. Satellite texture — fetch Sentinel-2 Cloudless composite from EOX WMS

The pipeline covers extents ranging from the Parbati Parbat peak (±0.10°, ~11 km) to the full Kullu district (1.3° × 1.2°, ~145 km).

Source: domains/parbati/parbati_dem.py (169 lines), parbati_textured.py (261 lines)