Geoprocessing
Online help: http://webhelp.esri.com/arcgisdesktop/9.1/index.cfm
Different ways to do geoprocessing in ArcGIS
- Basic stuff the buffering in ArcMap
- From ArcToolbox in either ArcMap or ArcCatalog
- Command line, either a shell or from a command window in ArcCatalog; if you run it in an ArcCatalog window it helps you type the right args. Not quite sure why anyone would want to use the command line this way...
- Model Builder can be used to invoke standard tools or to call your scripts.
- Scripting usually with Python, then calling scripts from one of the above methods.
TIPS
ArcCatalog Tools->Options->Geoprocessing
Check the box to allow overwriting of files, so that you don't end up creating numbered files like water_1 and allstreets_3
Set your default tools directory to something reasonable.
ESRI
See also Model Builder
27-Jun-2011 At ArcGIS release 10 they realized ArcPy which was a huge step up. It's pythonic now.
31-Dec-2007 update: ArcGIS Desktop 9.3 includes a new python wrapper module that makes working with ArcObjects a lot easier. I am using ActiveState 2.4.3 with it with good results. It breaks if you try to move up to 2.5.1.
You now just use the python line "import arcgisscripting" instead of directly invoking the COM dispatch thing.
Old notes from ArcGIS 9.1
This guy seems to have slogged through a lot of development with it and collected useful notes: http://www.ollivier.co.nz/support/python.shtm
I can add a new one to his list. I was getting error messages on setting gp.workspace = 'foo' where foo is a valid path. It's because the gp object was hanging around in pythonwin's memory. You should be able to say 'del gp' but I gave up and restarted pythonwin to fix it.
When working with ArcToolbox 9.1 and Python 2.1 I have been having lots of crashes in PythonWin. Using it on a computer with ActiveState 2.4.3 I have not been experiencing the same problems. I am going to try installing 2.4x without removing 2.1 so I can fall back on it... I followed the instructions above.
It still crashes. Oh joy. It does not even crash faster.
Open source
ESRI has broken down and started to use http://www.gdal.org OGR/GDAL] for some things. I need to get the Python bindings installed...
23-Aug-2006 Python+OGR probably not worth messing with right now. From the OGR site: The Python API isn't really well documented at this time, but parallels the C/C++ APIs. The interface classes can be browsed in the pymod/ogr.py (simple features) and pymod/osr.py (coordinate systems) python modules. The pymod/samples/assemblepoly.py sample script is one demonstration of using the python API.
ArcGIS 10 + Python + GDAL
See How I build GDAL for Windows
FWTools
FWtools installs a GUI called OpenEV_FW and a shell environment. It comes with python 2.3.4 which is old. I think Frank does this because it's stable and test with his tools. Going to a newer version means the DLL won't work so you'd need to compile your own.
