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.
With the new version of ArcGIS coming out soon (9.4, now 10, tomorrow maybe X), it is nice to revisit the things I would love to see change in the geoprocessor. This is by no means a study on what is missing or what ESRI is doing wrong, but rather what I would like to see in the future. If you have any suggestions, please do write a comment and I will gladly add them to the post (and attribute the addition to you).
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 »
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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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 162009
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 112009
There are multiple problems analysts face when they have to deal with processing multiple data files. There is the issue of identifying similarities and commonalities in files, and then of course how to automate the processing so they don’t have to run a program multiple times with the same parameters of separate files. In the world of ESRI’s GIS analysis, this can be performed quite easily with the help of Geoprocessing, either in Python or the Model Builder. Below is sample code that allows the iteration over a number of datasets. Continue reading »
Jun 042009
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 »
Accessing Geometries using the Geoprocessor is an easy task when one uses Python. All you need is a cursor to a feature class and you are there. Some terminology may help, before we dive into the code. Continue reading »
