6 Tips for Developers Moving into GIS


2010-03-16 14:49




general, opinion, programming


developers, neogeographers, programming, tips






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With the rise of the neogeographers, along with the increased awareness and use of GIS thanks to the web, more and more positions are open for developers looking to move away from writing business accounting logic, and into the exciting “new” world of spatial data. I’ve noticed a few gotchas that have happened to developers with no GIS background while working on projects, so this list may at least raise awareness of some of the hurdles.


1. Get to Know your GIS Application

Most desktop development in GIS involves building extensions to an existing application using an existing programming library. In order to avoid reinventing the wheel you need to be able to use your GIS desktop package.

Before developing any automated tasks, manually go through the process to get a feel for any issues that may arise, and learn some of the terminology used by the program for the various functions. If the application has an option for hatched polygon fills, this option is also likely to be buried somewhere in the API. If you can’t find what you are looking for then run what you are trying to accomplish past a GIS user.

2. Learn some Basic Terminology

A good GIS glossary can be found on theESRI site, and it is also available in a A to Z of GISimage1 book. Of course nothing is simple as different software companies use different terms for the same thing so a Layer in ArcMap, is the equivalent of an Overlay in Google Maps.

If you want to find all the point addresses within 100m of a road you don’t need to spend weeks writing your own algorithms (I’ve seen this happen..), armed with a good GIS vocabulary you will be aware of the term buffering and can find how to do this programmatically in your software. Your new employer will prefer a basic question related to GIS or geography than 2 weeks developing a function that could be achieved with a single line of code.

If developing for the web there are a plethora of technical terms you will have to learn such as WMS, WFS, GeoJSON, GeoXML (most web standards also seem to take a Geo- prefix), KML, tile caches etc.

3. Get to Know your Datasets

image2 Half the battle with GIS development is getting data into a consistent format so you can run analyses on it. Get ready to start dealing with Excel spreadsheets, strange proprietary GIS formats, and file dumps that may or may not resemble databases. Remember that many of these datasets will be coming from GIS technicians rather than database developers. Safe’s FME can convert pretty much anything to anything else, and the translations can be saved and automated saving plenty of time.

Spatial data is not too complicated. Most features can be represented as points, lines, or polygons. Obviously things can get more complicated such as multipart polygons, doughnuts, geometric networks etc. but these features are not overly common. However learn about projections and how to reproject data. If your data is invisible with no errors then projections are often the issue.

There is also a semi-mythical object called metadata. If this doesn’t exist expect to spend plenty of time trying to track down what various fields mean, if look-up tables are available, and what projection the data is in.

4. Learn the differences between Raster and Vector.

If you want to display cells across a whole country then you will need to user raster, vector data will take an age to draw. Don’t make the mistake or drawing lots of nicely coloured geometric squares.

5. Find New Programming Forums

You may need to look further afield than StackOverflow for answers to technical problems (except maybe Google Maps on Android). Where to look depends on what you work with. Each major GIS vendor’s site is likely to have a forum which serves as the focal point for all developers using their software, for example ESRI has widely used user forums. For open source mailing lists seem to be the support technology of choice - here Nabble is your friend.

6. Bring your experience

Many people working in GIS come from a geography background, and are self-taught programmers. If you are working with a team then try to introduce concepts that are now commonplace in other areas of software development - source control, unit tests, object programming etc.

You may also see GIS users spending hours doing things by hand that can clearly be automated. If you know some Python then you will be able to save hundreds of man hours with geoprocessing scripts for both proprietary and open source applications. For unknown reasons Python has become the scripting language of choice in GIS. Its good for web GIS too.

Along with software development practices any previous experience with databases will be huge plus. If you know what the following are you will soon become a very productive member of staff - primary key, normalisation, relationships may be new concepts to your new organisation. Geodatabases introduce a few new concepts, such as spatial indexes, projections, and geometry types, but if you have a good grounding in standard databases you will pick things up easily.

Feel free to add anything I’ve missed in the comments below, and good luck!



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