Free GIS Data

Through our work with YANKEE, The Old Farmer’s Almanac and Elections PEI we’ve had to become adept at understanding the basics of GIS — Geographic Information Systems, or, more generally “maps on computers.” And we’ve had to become adept at finding sources of free GIS data.

The United States is much more enlightened about the public use of government information, and so a lot of U.S. Government generated GIS data is freely available online. Ironically, it’s often possible to get Canadian data for free from the U.S. too. Three excellent starting points are:

  • The Map Layers Warehouse of the U.S. National Atlas has a great selection of base layers, running from basics like roads and state lines to magnetic field, zebra mussels infestations and time zones. I’m a particular fan of their Shaded Relief of North America. They make their data available for free download in ESRI Shapefile and SDTS formats.
  • The AWIPS Map Database page, from the National Weather Service, is, as you would expect, weather-focused. But they do have some basic layers, like Canadian provincial and territorial boundaries, that aren’t available from the U.S. National Atlas.
  • The Canadian GeoBase site is proof that Canada is catching up. In particular I’ve found their National Road Network is a useful resource (although, at least for PEI, it’s currently without street and road names attached; this is coming in a later revision).

Put the data you can get from those three sites together with an open source mapping application like MapServer and you can create powerful mapping applications (like this and this) at no capital cost.

What’s missing from the mix is, alas, an open source GIS editing application — something along the lines of MapInfo or ArcView. There is GRASS, but I have found its complexity so insurmountable as to be almost useless. I’m sure it can be very powerful if you are willing to mount an assault on its learning curve, but that would take the kind of time and dedication I can’t afford.

Even without a GIS app to create new layers, however, you can still, using MapServer and PHP or Perl, programatically create new layers — both points and polygons. Although this isn’t “point and click,” it does make it possible to map your own data on top of others’ base layers.

I’m pretty convinced that things are heating up inside the nexus GIS, GPS, telephony and the web: these tools, and this data, can drive a lot of interesting experimentation in people’s basements.


Peter Rukavina's picture
Peter Rukavina on August 19, 2004 - 19:31 Permalink

Another very useful resource, although not free (but very low cost, relatively speaking), is ZIP Code Download, from which you can purchase point files of the centre of ZIP code (U.S.) and postal code (Canada) centroids.

David Richardson's picture
David Richardson on August 19, 2004 - 20:30 Permalink

Peter, I know you’ve sent Canvas packing, but a version of the program does exist that has some of the capabilities that you’re looking for. For instance, it will import ESRI SHAPE files.

It isn’t going to put any true GIS systems out of business, but you might want to have another look.

Peter Rukavina's picture
Peter Rukavina on August 19, 2004 - 20:33 Permalink

Canvas will READ shapefiles, but it won’t WRITE them.

David Upton's picture
David Upton on August 19, 2004 - 23:21 Permalink

You should check out the GIS work going on in the Annapolis Valley of Nova Scotia The Nova Scotia Communty College, Annapolis Valley Campus (Centre of Geographic Studies, delivers post grad programs and is heavily involved in applied research projects.

Among other things, their applied research folks are developing GIS datasets and LiDAR applications on environmental health (air and water quality) at the landscape scale.

Between these guys and the folks at UNB, Atlantic Canada has two very succesful programs on the go.

Norm Rukavina's picture
Norm Rukavina on August 20, 2004 - 01:22 Permalink

Peter: You didn’t mention ArcExplorer, the freeware program from ESRI that can open shapefiles. Not much use for generating new GIS files but certainly useful for exploring existing ones.


Marcus's picture
Marcus on August 20, 2004 - 18:33 Permalink

With a smaller landmass than Canada’s, plus a $450 billion/year defence budget (some of which goes toward mapping), it’s no wonder the U.S. can give their data away.

Chris Corrigan's picture
Chris Corrigan on August 21, 2004 - 03:20 Permalink

Also, friends of mine who live here on Bowen Island and work for NRCAN have created the Bowen Island GeoAtlas which you can view to your heart’s content at

I think it’s a great example of how a community can make use of data. We even have some blog stories cross posted to the database to give a semantic lean to all the pretty stuff.

Thor Henrikson's picture
Thor Henrikson on August 23, 2004 - 14:58 Permalink

We’re using (a very expensive) ESRI ArcIMS map server on our new website, as a way of navigating our huge shipwreck database. A GIS server was, (and still is), quite a learning experience, but now we’re hooked and can’t stop of thinking of different ways to use our map server. (The global locations of all toxic and/or explosive marine dumping sites is one we’re hopefully going to do, along with hopefully a few others). The map interface is addictive, and we’re finding in our server logs that people are using it as hoped, (including using the map to drill down in to the shipwrecks that have streaming video clips), and are staying up at night doing it. Shipwreck Map Crack.

I hope I’m not out of bounds here but since there is no opensource server available we’re definitely considering partnerships to provide the server capacity and production expertise to others who don’t want to (or can’t) take the whole server thing on by themselves. If anyone has a database or content where a map interface would make sense you should come talk to us -Atlantic Canada and beyond. We’re hoping that if there is interest then we can offer low cost GIS hosting services for others who could never have afforded it on their own.

If it looks viable we could really help others out. (I’m lucky to work for a very enlightened boss.)

Thor Henrikson's picture
Thor Henrikson on August 23, 2004 - 15:44 Permalink

Oops. I of course totally overlooked the Mapserver project ( which Peter mentions in the original post. I did read it, honestly.

We’re using Arcview for our shapefiles but interestingly we were told that the process can be set up to be done on the Unix server itself using Unix tools. I’ll check in to that.

Katie's picture
Katie on August 25, 2004 - 17:39 Permalink

Can I just say that GIS is the greatest tool…but I have to take offense at your comment that they are “maps on computers”. That is only 1 component of a GIS — it is the ability to do spatial analysis that is the key. I know, I know, most folks aren’t going to do that…they just want cool maps, but I had to put in my 2 cents worth.

The thing I like about ArcView is that I can customize it to do what I want using scripts (VBA or avenue depending on version you are using) — making it an even more powerful tool.

The free US data is due to the fact that if american tax dollars pay for it, it is supposed to be in the public domain (with some obvious exceptions like all that classified stuff).

Peter Rukavina's picture
Peter Rukavina on August 25, 2004 - 18:24 Permalink

Katie, my “maps on computers” comment wasn’t meant to disempower GIS, simply to de-acronym it. You’re right: “maps on computers” doesn’t do justice to the wonderful palette of opportunity that GIS offers.

Marcus's picture
Marcus on August 26, 2004 - 23:15 Permalink

In speaking about the file formats of GIS data… ESRI, MapInfo, Intergraph, GRASS, IDRISI, etc. all make the file specs public knowledge through industry white papers. Those who work with the data long enough learn how to write their own format translators so you can get away with using opensource software and proprietary data formats.