gdal_contour

generates contour lines from elevation data

TLDR

Generate contours

$ gdal_contour -a [elev] -i [10] [dem.tif] [contours.shp]

Specify interval

$ gdal_contour -i [100] [dem.tif] [contours.shp]

Fixed contour levels

$ gdal_contour -fl [100] [500] [1000] [dem.tif] [contours.shp]

Output to GeoJSON

$ gdal_contour -f "GeoJSON" -i [10] [dem.tif] [contours.geojson]

Generate 3D contour polygons

$ gdal_contour -p -3d -a [elev] -i [50] [dem.tif] [contours.shp]

SYNOPSIS

gdal_contour [options] input output

gdal_contour generates contour lines from elevation rasters (DEMs). It creates vector features representing lines of equal elevation.The tool supports regular interval or specified level contours. Output includes elevation attributes for labeling. Multiple output formats are available.gdal_contour is used for cartography, terrain analysis, and visualization of elevation data.

PARAMETERS

INPUT

Input elevation raster (DEM).

OUTPUT

Output vector file.

-a NAME

Attribute name for elevation.

-i INTERVAL

Contour interval.

-fl LEVELS

Fixed contour levels.

-f FORMAT

Output format.

-b BAND

Source band number (default: 1).

-3d

Force production of 3D vectors instead of 2D.

-p

Generate contour polygons rather than contour lines.

-off OFFSET

Offset from zero relative to which to interpret intervals.

-snodata VALUE

Input nodata value to ignore.

-nln NAME

Output layer name.

-q

Quiet mode, suppress progress output.

CAVEATS

Quality depends on DEM resolution. Dense contours may be slow. Output size varies with complexity.

HISTORY

gdal_contour is part of GDAL (Geospatial Data Abstraction Library), providing contour generation from digital elevation models for mapping and analysis.