Latest Contributions by DanPatterson_Retired

The coordinate system of both files need to be the same and the file you are using to clip needs to partially or fully overlay on the file you want to clip ... View more

From experience, either run the tool from Arctoolbox within an ArcMap (not a script outside of ArcToolbox while arcmap is running) or don't crank up Arcmap at all. ... View more

In short...no, static objects (ie shapefiles) can't be moved unless edited, check out the tracking analyst should you wish to show temporal animatiosn ... View more

If you can work in raster format, have you ruled out zonal statistics style operations? http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z000000w8000000.htm you will have to calculate percentages after. ... View more

You might get some ideas from this http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=F0B54854-1422-2418-A0F6-37042FE94472 ... View more

you have to set the extents explicitly in your Environments to be the extent of the layer used to clip the input raster ... View more

then cell statistics may be what you are looking for http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z0000007q000000.htm ... View more

did you run tests to assess the comparison? ... View more

haven't used it in a while but is there a need to build the soma line?  I got the impression from the help file for 9.3 that you just needed to pass on a list of grids which you already have in your rasterList variable...could be wrong, but it would only seem logical unless the ListRasters doesn't provide a list formatted properly for use in subsequent SA tools. ... View more

did you rule out cell statistics with the sum option? http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?id=6283&pid=6281&topicname=Cell_Statistics You may be running into problems if the grid list is too long, in which case, you may need to do it incrementally ... View more

why not use the plus syntax from arcpy.sa import * outPlus = Plus(inRaster1, inRaster2) http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z00000096000000.htm for further information ... View more

see the standalone script example in the help file, you need to checkout the extension http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z00000096000000.htm ... View more

have your ruled this out as simply being a symbology issue?  have you tried to float one of the rasters in the raster calculator prior to division to ensure floating point division?  Have you investigated the histogram for the data? ... View more

Install Pythonwin from your installation CD, it provides a better IDE than the normal one...of course you could progress to better IDEs but you can customize Pythonwin to suit most of your needs ... View more

Chris After finishing two terms of teaching and warning students about the differences between these tools, the preference seems to use the Define Projection tool erroneously...some even thought the Project tool had to do with "projects" and not "projecting" even though it is appropriately located in the toolbox (grief!).  In any event, the warning icon needs to be huge and flashing...or perhaps a popup, or the tool fails if the input and output extents don't jive (ie going from DD data to UTM). ... View more