cityImage.assign_elevations_from_rasters#

cityImage.assign_elevations_from_rasters(nodes_gdf, buildings_gdf, dtm_path, surface_path=None, z_col='z', base_stat='mean', top_stat='max', all_touched=False, min_valid_elev=-50.0)[source]#

One-stop elevation assignment from rasters, for cities without height data.

Given a bare-earth DTM (terrain) and optionally a surface model (DSM — first-return elevations including rooftops; the raster often shipped under the generic name “DEM”), this assigns:

  • node z (z_col): terrain elevation sampled at each point — the observer elevation used by the 3D sight lines;

  • building base: terrain elevation under each footprint;

  • building height (only when surface_path is given): above-ground height as top-of-surface minus base.

With a DTM alone, heights are not derivable — only z and base are set; supply heights from a detailed layer or OSM tags instead.

Non-destructive: results are merged back onto the full input frames, so features outside the raster extent keep their rows (with NaN elevations). Either nodes_gdf or buildings_gdf may be None to skip that side.

Returns:

  • tuple(GeoDataFrame or None, GeoDataFrame or None) – (nodes_gdf, buildings_gdf) with elevations assigned.

  • Requires the optional ``height`` extra (rasterio and rasterstats.)