Geography Reference
In-Depth Information
form of SVG or KML data combined with a custom Google Maps object. Raster tiles are just
the tip of the iceberg.
Statistical Outputs
Outputs in this group are the complete opposite of graphical outputs. Data is often the by-
product of several GIS-SQL operations based on the input data and processes going on
within the system. Just like general database data, from this output you'll get facts and
figures that can be used to report statistics to management or marketing teams. The reason
we treat this separately, however, is because of the nature of the information.
While you might be tempted to just say, "It's only numbers," in some cases it's numbers that
have no meaning unless there is some GIS input involved. As an example, let's say we have
a number of geographic areas representing plots of land, and with each of those areas we
have a monetary value for that plot.
We can easily say, "Give me the values of each plot in descending order," enabling you to
see which is the most expensive piece of land overall. This is where the difference stops,
however. Let's say we now know that all land in a district has a 1% tax for every square
meter a plot consumes. We know by looking at a graphical output of the map that the
visually bigger areas are going to be more expensive, but you can't convey that to a
computer.
You can, however, ask using GIS-SQL for a statistical analysis based on a percentage of
the land's plot value multiplied by however many square meters are in the defined area
boundary.
Manual Processing Software
Anything in the system that requires an operator and some software to make changes falls
under the category of manual processing software. Typically, this is both an input and an
output because in most cases this involves changes being made to the underlying data
manually.
This is usually the area where you'll see large GIS packages such as ESRI, DigitalGlobe,
and MapInfo used. We'll cover some of these later. An example of what might be performed
at this stage is boundary editing. Let's say that you added some town boundaries as area
definitions several years ago, and since they were first added the towns have increased in
size. You would then find a GIS expert who, with his or her chosen software and some
satellite imagery, would edit your boundary data so that its definition better fits the newly
expanded imagery.
Automatic Processing Software
Operations running at this stage are generally not much different than those being run
manually. The reason we see a clear separation is because some processes simply cannot
be automated and need a human eye to pick out details. Going back to our previous
