Monday, April 21, 2008

Quantum GIS: First Impressions

As I mentioned in the welcome to this blog, part of why I want to write here is to grow professionally by trying technologies outside the four walls of my FalconView / ArcGIS office.  Quantum GIS is a piece of GIS software not much different from FalconView in its mission.  It displays vector layers, raster maps and imagery; it also includes some task-oriented geoprocessing and editing capabilities.  Being a typical engineering type, I only spent a few minutes reading the instructions, too eager to dive right in and start trying the thing.  Here are my first impressions of Quantum GIS.  Please keep in mind that these are impressions coming from an experienced GIS user with no previous exposure to QGIS, so some of my facts about QGIS may be incorrect, but I probably represent a typical GIS user who would be considering this type of solution.  Here are my impressions from my short test drive.

Right off, I discovered support for drawing GeoTIFFs and Shapefiles.  The picture above and left is an image of the Georgia Tech campus drawn in QGIS.  (I included the same image in FalconView on the right just for kicks.)  The image below shows the Shapefile.  Right off I was encouraged: QGIS is easy and intuitive to use.  Note that I opened the GeoTIFF in an Ubuntu QGIS install and the Shapefile in a Windows install.  This is a nice thing about most open source software: the authors generally do a good job of achieving platform independence.

Notice that I don't have the Shapefile and the GeoTIFF drawing together in the same window.  After a little poking around, I wasn't able to get this to work properly.  I assume my difficulty was due to differing coordinate systems between the two files and my lack of experience setting up coordinate systems in QGIS, but I'm still not sure.  Since I was going for first impressions, I gave up trying the get them to draw together after a short time.  (ArcMap and FalconView generally transform different coordinate systems to draw together without much difficulty, though there is some danger to doing this.)  I did get WMS support working, but I could only get their sample WMS servers to draw.  I suspect that with some more experimentation (or actually reading the instructions), I could get support for different coordinate systems and WMS working better.

There are a few other features I quickly discovered that are worth mentioning.  As you would expect, QGIS includes good support for custom symbolization of vector data and exporting a map to an image file.  There is also a neat feature where you can reclaim real estate on the map by pressing CTRL + T / T to hide and show the toolbars.  Finally - and I've saved the best for last - if you're in the market for something to create and edit your own Shapefile, QGIS does this nicely.  Unlike ArcMap, where feature editing, though powerful, is about as natural as breathing underwater, QGIS makes it intuitive.  (Shameless plug: You can create and edit Shapefiles in FalconView via the GIS Editor, which is essentially the same as doing it in ArcMap.)

I very much want to revisit, in a future posting here, the advanced programmatic features of Quantum GIS.  There is support for an interactive Python console (I'm a Python novice, so maybe this will be the push I need to learn it better), and there is support for plugins to QGIS.  I spent about 30 minutes poking around on the QGIS web site, wiki, and Internet in general to learn more about plugin capabilities and how to write one, but I couldn't find anything useful.  Some quick e-mail correspondence with a QGIS developer pointed me here.  (And there we find yet another advantage to using this active open source project: it's not too hard to find help from the project volunteers.)

I'll sum up my initial impressions with Quantum GIS by saying that it's a maturing product worthy of applause.  It does most of what it's supposed to do with ease, and I suspect that with a little more experience, I could overcome the hurdles I experienced.  I enjoyed playing with the tool, which says a lot since I have a pretty short attention span.

If you want a quick demo of the basic capabilities, check out this video.

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