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About
Dr Mike J Smith
Senior Lecturer in GIS,
Kingston University
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Pythonian Adventures 1
OK, up front, I hate programming. I'll agree that there is a great deal of satisfaction when a script or bit of software finally works and you can run a complex process automatically. And whilst I quite like the pseudo coding part (working out a solution to the problem), the actual process of getting the syntax, writing it and de-bugging it is incredibly frustrating.
That said, anyone "doing" GIS will at some point have to do some kind of coding and for many that will mean ArcGIS. ESRI, as with many companies that developed software in the 80s and 90s, have a history of scripting languages. And in scripting I mean taking existing software functions, making them accessible through a script interface and automating procedures. This was often developed to allow complex tasks to be "recorded" and re-run, but also allows looping procedures to be developed and therefore repeating a process iteratively (i.e. applying a buffer routine to 1000 files).
In ARC/INFO this was AML, in ArcView 3.x this was Avenue and in ArcGIS.... well they removed scripting. Of course by that point Microsoft was touting Visual Basic (and VB for Applications) and programmatically accessing COM Objects within software. This is a fantastically sophisticated approach because, with ArcGIS, incredibly low-level properties and methods are opened for access. Unfortunately it is not for the faint hearted and even the simplest of processes will require 50+ lines of code.
And the alternative? Well there WASN'T one. This was one of several "gotchas" that ESRI shot itself in the foot with when in released ArcGIS 8. Because whilst VBA allows for some really good extensions to be written (and I've blogged about Hawths Tools, Graphics and Shapes, X Tools ET Tools etc), the average GIS "analyst" may well not have the time or inclination to get that deeply involved. In these instances most people want to use a scripting language. O dear....
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