Often times people write geoprocessing scripts that others try to incorporate in their work. This is done through modules or packages in Python. This is wonderful when one wishes to share their work, but it can also be bothersome if the module you are loading assumes that there is no geoprocessor loaded. This little script will help you safely load the geoprocessor object, either from an instantiation by the main program, or from scratch.
Feb 03
After a long delay, it is time for the third installment of understanding the Geoprocessor Programming Model that will deal with the Describe object. If you missed the last two parts, feel free to look at them first (Part 1: understanding what the geoprocessor is, and Part 2: accessing data with the geoprocessor). As always, comments are welcomed and encouraged. Continue reading »
Oct 19
In the first part of this series I covered access to the geoprocessor and how one can navigate the first part of the diagram of the model. If you are not familiar with the geoprocessor, please have a quick look at that post to understand the geoprocessing model ESRI provides.
In this post I will finish covering the bottom left part of the model that deals with direct access to features and their geometry. In order to do that, we will discuss cursors, features and geometries.
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Oct 16
A question often asked when people venture into the wonderful world of Python Geoprocessing with ESRI is how one can read the programming model they make available on their website. As it may not be easily interpreted when one begins programming, I will do my best to unpack it and explain how one can use it more effectively. All images presented here are extracts from the actual model presented by ESRI on their website.
Jul 16
There are some fundamental differences between geoprocessing performed in ArcGIS version 9.2 and 9.3. While I will not cover them all in this post, I will attempt to show the most fundamental differences that people seem to encounter more often.
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Jun 17
Writing Excel files using Python is quite easy, using the xlwt package. Similar to xlrd mentioned in an earlier post, xlwt allows one to write Excel files from scratch using Python. Continue reading »
Jun 15
It is often the case that the freely available data online are in Excel format. If one has Excel, then one has the ability to do some sort of basic manipulation of the files. But if Excel is not available, or your analysis software does not read Excel files, there is another way: use Python to manipulate Excel files. Continue reading »
Jun 04
In the many methods present at the Python interface to ArcGIS (Python geoprocessing through the arcgisscripting module), one that is quite useful when processing individual elements on a feature class is called MakeFeaturelayer(). The behavior, while predictable with a small number of runs, can prove problematic when dealing with large datasets. Continue reading »
