Topography of a region - Python

Introduction

An example of Alta-joki Alta river.

https://caltopo.com/map.html#ll=68.8546,23.64807&z=8&b=mbt

Mostly needs an API.

• DEM Digital elevation model
• DSM Digital surface model
• DTM Digital terrain model

Python GIS

• folium
• geopy
• GeoPandas

Earth Model

DEM files (likes SRTM data) with

• Rasterio
• GDAL

Norwegian national DEM (Kartverket). The Norwegian Mapping Authority provides very high-resolution DEM data (down to 1 meter).

• https://hoydedata.no

Global DEMs (digital elevation model). No need super high resolution. Common datasets:

• SRTM (~30 m resolution)
• ASTER GDEM (~30 m)

Open portals. You can use

• OpenTopography
• OpenDEM
• NASA EarthData

which gives eg GeoTIFF.

Open Topo Data

https://www.opentopodata.org/

11

import rasterio

with rasterio.open("dem.tif") as dem:
    for lon, lat in track:
        row, col = dem.index(lon, lat)
        elevation = dem.read(1)[row, col]

Downsampling the GeoTIFF

from rasterio.enums import Resampling

data = src.read(
    out_shape=(
        src.count,
        src.height // 10,
        src.width // 10
    ),
    resampling=Resampling.average
)