Basic Analysis of Point Data
Now that you are starting to build up your database of information on the
area where the landslides happened, you can start to do some analysis! This is the fun
part, if you're not too tired already...
Here's a clipped version of the oregon geology
coverage (SP 83-OR Custom Projection) for just your 4 counties. Go ahead and clip it to
just the 3 maincounties.
Here's some soils data (SP 83-OR North) that I
found. In the metadata it just said something about NRCS classification, so you'll have to
find out what that means. I would start here...
Now you want to find out what kind of spatial associations there are
between your different data sets and the landslides, assuming that there are any.
There are a lot of different things you can do: buffer the streams and
roads, do point in polygon analysis on the soils and the geology, reclassify the soils
data and the geology, look at slope (oh yeah, get a DEM of one of the the areas, let's see if that helps...), etc. You
need to try things that make sense, remember you're a scientist!!! So don't just spaz out
and run a bunch of tests. Think about it first, describe WHY you are doing it, and then
try it. Look in chapter 5 of Davis and chapters 7, 8 and 9 of Bonham-Carter for some
ideas. I'll try to get the Unwin book on reserve, too.
So, do this: try 2 or more analytical techniques on the data and see if
you can find anything that looks like a good predictor of lanslide potential. If you have
some statistical background, feel free to apply this knowledge, otherwise frequency
histogram types of charts are okay for summarizing your results. If you get something that
looks good, turn it into a map of high landslide risk. This
is your goal!
Remember to do a detailed write-up!
Addendum (for printing out black and white
patterns):
There was a problem with the patterns not printing correctly. The solution
to this is to load the carto.avp pallette in the Symbol Window. This pallette adds vector
patterns which apparently reproduce better on non-Postscript printers.
Steps:
Window-> Show Symbol Window...
Click on the far right button that looks like a painting pallette.
Click Load and navigate to ESRI\AV_GIS30\ARCVIEW\SYMBOLS (or wherever
Arcview is installed)
Double click carto.avp
This will add the additional patterns from carto to the end of you
pattern list.
Try out a few different hatch patterns until you find a combination of
patterns, grayscale, and black and white that is aesthetically pleasing.