Using IF statements with maths where the input is not an integer
Hi All
I've made a few scripts which using GDAL extract the value of a pixel within a given raster. The purpose is to work out the combine value of every pixel. I thought there may have been an easier way to do this but alas!
The code below extracts the pixel value at position X Y. The value is a floating point rather than an integer and thats where my problem lies. The if statement simply exports the value to a txt file. Other scripts take care of the rest ie change values of X Y and summing the resultant txt files.
However, I get the following message back when ever my statement is true because my value isn't an integer;
extract2.sh: line 4: [: 2.15787172317505: integer expression expected
Please note the raster file mostly contains zero values, and its only the values greater than zero I'm interested in, which is why I added the expression.
Any ideas how I can alter this code so the IF statement excepts integers? Alternatively if anyone knows of a faster method of quickly summing the values of a raster file, that would be equally useful.
Many thanks in advance for any assistance you can offer.
Andy
Last edited by vbe; 08-12-2011 at 09:50 AM..
Reason: please use code tags!
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Discussion started by: wisecracker
2 Replies
LEARN ABOUT DEBIAN
dans-gdal-scripts
DANS-GDAL-SCRIPTS(1) General Commands Manual DANS-GDAL-SCRIPTS(1)NAME
dans-gdal-scripts - A GDAL add-on set of utilities
o gdal_contrast_stretch - Contrast stretch and conversion from 16-bit to 8-bit
o gdal_dem2rgb - Generate hillshaded images from DEMs
o gdal_raw2geotiff - Convert raw binary files into GeoTIFFs
o gdal_get_projected_bounds - Project a polygon and return its bounding rectangle
o gdal_trace_outline - Trace the outline of an image and generate WKT or Shapefile
o gdal_merge_vrt - Merge individual bands into a single VRT image
o gdal_merge_simple - Merge individual bands into a single GeoTIFF image (8-bit only)
o gdal_landsat_pansharp - Pansharpening - works best for Landsat 7 images
o gdal_wkt_to_mask - Generate a bitmap of the area covered by a polygon
o gdal_list_corners - Prints raster geocode information in YAML format (similar to gdalinfo but gives YAML)
o
DESCRIPTION
This manual page documents briefly the Dan's GDAL Scripts set of commands. You can get a synthetic description of accepted options and
command line arguments by using -h option with every command. This set of tools is based on the GDAL/OGR library and provides some useful
simple manipulation of geo rasters and satellite data. Do not buggy GDAL team for possible issues with this software, this is a contrib-
uted set of programs.
SEE ALSO gdalinfo(1), gdal_translate(1), gdal_contour(1), gdaladdo(1), gdal_grid(1), gdaltransform(1), gdalmanage(1), gdal_rasterize(1), gdaltin-
dex(1), gdalenhance(1), gdalwarp(1).
AUTHOR
The dans-gdal-scripts tools were written by Dan Stalke for GINA, the Geographic Information Network of Alaska, a working group of the Uni-
versity of Alaska.
This manual page was written by Francesco Paolo Lovergine <frankie@debian.org>, for the Debian project (and may be used by others).
March 25, 2009 DANS-GDAL-SCRIPTS(1)