GIS contacts and DEM elevations

Use GemGIS to extract geological observations from spatial data. Establish the horizontal CRS, vertical units/datum, geometry type and missing-data policy before sampling. Model coordinates must share a projected metre CRS; converting horizontal coordinates does not transform elevations or their datum.

Extract contact vertices

The following function accepts a single-band DEM already in a metre projected CRS, with elevations in metres. dem is an open Rasterio dataset, not a path. GemGIS repeats attributes when a line becomes multiple points: do not overwrite those attributes using the original feature index.

import gemgis as gg
from rasterio.transform import rowcol
import numpy as np
from pyproj import CRS