Introduction - Desktop GIS: Mapping the Planet with Open Source Tools - page 2

Harrison ponders his next move—how to get all that good bird informa-
tion that's on his trail-weary notebook sheets into a form where he can
not only visualize it but even ask some questions (in other words, do
analysis). Harrison wants to be able to do the following:

• View the locations where he observed birds
• View only the locations where he saw the yellow-bellied Wonky
Finch
• Scale his locations (dots) based on the number of birds seen at
each location (more birds = bigger dot)
• See whether there is any relationship to the weather and the num-
ber or types of birds he observed

Harrison needs not only a good visualization tool but something he can
do analysis with. Harrison needs some GIS tools, and of course we offer
up open source desktop GIS as the solution to his mapping needs.

1.1 What Is Desktop Mapping?

Harrison has introduced us to a problem that we can solve with desktop
GIS software. So, what exactly is desktop mapping? Well, it isn't about
drawing a map to find your pencils, pens, stapler, and coffee cup. Desk-
top mapping is all about using software installed on your computer to
visualize and analyze data. Not only can it be used to meet Harrison's
bird-mapping needs, you can also create hard-copy maps, create data
out of thin air (well almost), and examine the relationships between
features.

Although it's true you can do all this with proprietary software, we'll
take a journey through the open source GIS landscape to see what we
can find. To get started, let's take a look at the kinds of things we can
do with open source desktop mapping tools. I've already told you that
Harrison's bird project can be handled quite nicely. Everybody likes to
“get on the board” quickly rather than learning a bunch of theory and
commands. We'll try to do the same here as you start your journey into
OSGIS, whether you are a beginner or a battle-scarred GIS geek.

To give you an idea of what we can do, you can see a rather simplistic
interpretation of the progression of things we can do with GIS (open
source or not) in Figure 1.1 , on the following page, in order of increasing
complexity. We'll take a closer look at each of these functions to help
you get an idea of what's involved with each. In turn, you can decide