This is the command gdal_contour that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
NAME
gdal_contour - gdal_contour builds vector contour lines from a raster elevation model
SYNOPSIS
Usage: gdal_contour [-b <band>] [-a <attribute_name>] [-3d] [-inodata]
[-snodata n] [-i <interval>]
[-f <formatname>] [[-dsco NAME=VALUE] ...] [[-lco NAME=VALUE] ...]
[-off <offset>] [-fl <level> <level>...]
[-nln <outlayername>]
<src_filename> <dst_filename>
DESCRIPTION
This program generates a vector contour file from the input raster elevation model (DEM).
Starting from version 1.7 the contour line-strings will be oriented consistently. The high
side will be on the right, i.e. a line string goes clockwise around a top.
-b band:
picks a particular band to get the DEM from. Defaults to band 1.
-a name:
provides a name for the attribute in which to put the elevation. If not provided no
elevation attribute is attached.
-3d:
Force production of 3D vectors instead of 2D. Includes elevation at every vertex.
-inodata:
Ignore any nodata value implied in the dataset - treat all values as valid.
-snodata value:
Input pixel value to treat as 'nodata'.
-f format:
create output in a particular format, default is shapefiles.
-dsco NAME=VALUE:
Dataset creation option (format specific)
-lco NAME=VALUE:
Layer creation option (format specific)
-i interval:
elevation interval between contours.
-off offset:
Offset from zero relative to which to interpret intervals.
-fl level:
Name one or more 'fixed levels' to extract.
-nln outlayername:
Provide a name for the output vector layer. Defaults to 'contour'.
EXAMPLE
This would create 10meter contours from the DEM data in dem.tif and produce a shapefile in
contour.shp/shx/dbf with the contour elevations in the 'elev' attribute.
gdal_contour -a elev dem.tif contour.shp -i 10.0
AUTHORS
Frank Warmerdam warmerdam@pobox.com, Silke Reimer silke@intevation.de
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