GME

Geospatial Modelling Environment

isectpntrst (Intersect Points With Raster)

Intersect points with a raster layer and writes the cell value of the cell containing each point to the attribute table of the point data source

Description

This tool intersect points with a raster layer and writes the cell value of the cell containing each point to the attribute table of the point data source. If the specified raster contains multiple bands, the tool returns one field for each band.

Note that points that fall outside the bounds of the raster layer will be coded with the rasters NoData value. If this is not defined the cell will be coded with the smallest value supported by the pixel data type, which may be zero. It is therefore highly recommended that you explicitly address the issue of points that fall outside the bounds of the raster to ensure that these NoData points do not bias any subsequent analysis you might do. Zero values can be mistaken for true values in some cases, so please pay special attention to this problem.

The fully supported common raster types are Grid, Imagine image (.img) GeoTIFF (.tif), and geodatabase rasters. Other image types are not supported by ArcGIS as 'raster datasets' and are unlikely to work with this tool (e.g. JPEG, PNG, MrSID, etc) even though they can be displayed in ArcGIS.

Syntax

isectpntrst(in, raster, field, [where], [update]);

inthe input point data source
rasterthe input raster data source
fieldthe new field name to write to the point attribute table and populate with raster values (if the raster has multiple bands the field name is treated as a prefix to which B# is appended, where # is the band number)
[where]the selection statement that will be applied to the feature data source to identify a subset of features to process (see full Help documentation for further details)
[update](TRUE/FALSE) if TRUE and you specify an existing field, the existing field will be updated rather than generating an error message (default=FALSE); warning: this option will result in overwriting of existing data and is therefore potentially dangerous.

Example

isectpntrst(in="C:\data\locs.shp", raster="C:\data\landcov", field="LCOV");

isectpntrst(in="C:\data\locs.shp", raster="C:\data\landcov", field="LCOV");

isectpntrst(in="C:\data\locs.shp", raster="C:\data\landsattm.img", field="TM5", where="COUNTY='WOOD' AND MONTH=7", update=TRUE);


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