gdaldem

analyzes and visualizes terrain elevation

TLDR

Generate hillshade

$ gdaldem hillshade [dem.tif] [hillshade.tif]

Create slope map

$ gdaldem slope [dem.tif] [slope.tif]

Generate aspect

$ gdaldem aspect [dem.tif] [aspect.tif]

Color relief

$ gdaldem color-relief [dem.tif] [colors.txt] [relief.tif]

Custom azimuth

$ gdaldem hillshade -az [315] -alt [45] [dem.tif] [hillshade.tif]

SYNOPSIS

gdaldem mode [options] input output

gdaldem analyzes and visualizes digital elevation models. It generates terrain derivatives including hillshade, slope, aspect, and various roughness indices.
The tool produces visualization-ready output from raw elevation data. Hillshading creates realistic terrain lighting. Slope and aspect support terrain analysis.
gdaldem is essential for cartographic terrain representation and geomorphological analysis.

PARAMETERS

MODE

Operation: hillshade, slope, aspect, color-relief, TRI, TPI, roughness.

INPUT

Input DEM raster.

OUTPUT

Output raster file.

-az DEGREES

Light azimuth for hillshade.

-alt DEGREES

Light altitude for hillshade.

-s SCALE

Vertical exaggeration.

--help

Display help information.

CAVEATS

Requires properly scaled DEM. Edge effects at boundaries. Large files need more memory.

HISTORY

gdaldem is part of GDAL (Geospatial Data Abstraction Library), providing DEM analysis tools for terrain visualization and analysis.