Opensource GIS: You get way more than what you pay for.

About a week or so ago I learned that Quantum GIS (QGIS), my GIS program of choice, had a new release out. It had upgraded from QGIS 1.7 to QGIS 1.8. “Oh shoot,” I thought, “Now my 1.7 install and all of its plugins and whatnot is out of date, support will cease, and I’ll have to shell out a pile of cash for the new version. Wait… this is QGIS; not ArcGIS. I’ll just download the new version for free, stick in all the plugins for free, and keep on happily GISing away. Hooray for the new version!” That is one of the beauties of the opensource GIS movement.

3D image done in GRASS within QGIS. Oooooh. Pretty.

As I mentioned in my return to blogging post, I’ve been tinkering with a handful of free, opensource GIS programs. These are pieces of software developed, in most cases, by a widespread group of users who were not content with the commercially available offerings (mostly ArcGIS), and decided to make their own products to suit their needs. The results are uniformly excellent programs, at least as capable as their commercial couterpart(s), and free to anyone who can get a copy (easy to download). The broad user community contributing to building the software results in a tremendously varied toolkit of GIS processes. Some programs are relatively easy to use, others require something of a learning-curve, but all get the job done.

My interest in these came with my resolution a few years ago to stop pirating software. In my reckless youth I thought little of finding cracked versions of programs online and installing the (often virus-ridden) goodies on my PC. However, as a generator of intellectual products, I came to empathize with the folks who make the programs, and decided to curtail my deviant behaviour. Over the course of the next few months I learned about the wonders of educational pricing. Photoshop CS4 seemed like a steal at about $200 instead of $1500 or $1800 or whatever a full license costs. Of course, once I am no longer a student (hah! That’ll be the day!) I must either buy a regular license or resign myself to being a criminal. ArcGIS is an even better deal at the moment: educational licenses are somewhat less than $100 while regular users are tapped for over $1500 again- even more for additional modules! (Surfer 11 is ~$700, by the way. No student discount that I’m aware of.) That presents something of a conundrum: I can take advantage of the educational discounts while I’m a student, but then once I’m out of school I’m stuck with a skillset that requires a batch of pricey programs to be of any use. Alternatively, I could get on the opensource train and learn the free programs before I am no longer eligible for educational pricing. Clearly, I have followed the second path.

 

QGIS

Quantum GIS (QGIS) is my favourite of the opensource GIS programs. It is the most intuitive to use, produces excellent maps, and has dozens (if not hundreds) of user-created plugins designed to provide greater functionality beyond the basic program features. The GUI is easy to use, the buttons are plentiful, the menu terms are logical, and it seems to have plenty of power behind it. Even better, among the QGIS plugins is an integrated GRASS GIS plugin that allows you to run GRASS within the QGIS program. Thus, QGIS’s logical, easy layout and buttons can be paired with GRASS’s mega-power and mass of GIS processes. Also, QGIS can run natively on my MacBook Pro (as well as on Windows and Linux).

Working map of the Lillooet region in QGIS, showing lakes and major rivers, along with terrain mapped to show slope (darker tones are flatter) and elevation (L-H: Blue; Green; Red; Orange).

 

GRASS

GRASS was apparently initially developed by the US Military, and was then ‘released into the wild’ for other developers to keep going. It has grown into perhaps the most powerful of the free opensource GIS programs (as far as I can tell). Unfortunately, the user-interface is far from intuitive, and even just opening files can be a challenge for the first-time user with no GIS training. Fortunately, like QGIS, there is no shortage of online help, with text and video tutorials, books, forums, and more. I have found that using GRASS within the QGIS shell is an effective way to circumvent some of GRASS’s user-interface quirks while still capitalizing on its power and potential. Interestingly, from an archaeological perspective, Michael Barton from ASU is one of the major players in GRASS development. GRASS also runs on Mac (and Windows/Linux)

A Basic DEM with some elevation shading in GRASS.

SAGA GIS

I have limited experience with SAGA. It would seem that SAGA, with its hundreds of modules, is comparable to GRASS in terms of analytical power. It is also the easiest program to use for generating a 3D terrain model from a DEM (digital elevation model). Unfortunately, other aspects of SAGA are sorely lacking. Namely, there does not seem to be much of a map-composer tool for adding north-arrows or scale bars to maps. Also, the colour-ramp device will make you tear your hair out. Want to make an elevation colour-code based on specific height increments? Good luck. Whereas GRASS and (especially) QGIS can do this with no trouble whatsoever, SAGA will require unreasonable fiddling and tweaking of the bizarre colouring interface. Perhaps if I ever learn how to code and whatnot, I will try my hand at fixing these issues. SAGA GIS does not run natively on Mac OS X, but works on Windows and Linux.

 

3D map in SAGA. Note that since SAGA does not run natively in OS X, I am running it in a Linux guest (ArcheOS- an archaeology-specific Linux build!) in Virtualbox.

gvSIG

I fired gvSIG up a couple of times, but got nowhere fast. One of my chief requirements is that it is fast and easy to open DEM files. These are digital elevation models that are freely available from NASA as well as from the Canadian Government. They form the basis for contour maps, hillshades, drainage calculations, etc. etc., as well as those pretty 3D images. Unfortunately, I can’t make heads or tails of how to open them with gvSIG. Admittedly, I’ve only spent about 5 or 10 minutes playing around, and have not yet delved into the manual, so chances are it will turn out to be dirt simple once I put in the effort to learn how to do it.

There are a few other programs out there, but I have not tried them out. The four mentioned above seem to be the biggest, best known, best supported, and most actively developed. As I said, I have really enjoyed QGIS, and I foresee it being my go-to GIS program (unless a prof or employer explicitly demands that I use ArcGIS sometime in the future).

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3 Comments

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3 responses to “Opensource GIS: You get way more than what you pay for.

  1. Nice article. Started a GIS masters 6 months ago, one of the reasons being a decent amount of hands on arcgis. I have a Microsoft systems engineering background starting 15 years ago so arcgis is probably just the ticket. Just recently though, I have started really appreciating the whole open source movement. I think QGIS sounds worth a try dave

  2. nwaber

    Hi Dave,
    I highly recommend giving QGIS a whirl. GRASS seems to have a bit more ability, but with the integrated GRASS module within QGIS, you get the best of both worlds. If you get it going, I’d like to hear your thoughts on the comparison between QGIS and ArcGIS from the perspective of someone with more training and experience. My autodidactic approach occasionally leads to skills plateaus that take a pile of reading and tinkering (and thus time- not too plentiful these days) to get through. I’m currently taking a mapping course too, where I’ll finally be getting some ArcGIS training, so I may be posting more on this topic in the not-too-distant future.

  3. I have to say I really adore your blog, the way
    you write is awe inspiring!

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