Displaying two layers on one map

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12-05-2012 09:12 AM
LindsayBalestra
New Contributor II
Probably a simple thing I'm trying to do...

I have two layers of data - race and owner occupancy rates. I have my race data as a graduated color ramp of 5 classes (20% increments). I also have % owner occupied units which I am showing as either blank for 0-75% or striped lines for 75%-100%.

What I really want to show is the change from 2000 to 2010 in occupancy rates. Right now I am making one map with 2000 race and occupancy data, and another for 2010 race and occupancy data. I'd love to just have a map of 2010 data showing the change in occupancy rates... either by having the 2000 and 2010 occupancy data on top of each other, or maybe showing the change.

However, I can't seem to make any map look good with 2000 and 2010 data on top of each other; the colors always look hideous and you can't really tell where the losses in occupancy are (which is what I ultimately want to show). Also, I've attempted to clip, intersect, merge, you have it and I can't seem to end up with the shapefile I want.

Do you have any tips on how to overlap the 2000 and 2010 occupancy data? I've tried changing the angle of the lines, changing the color, etc but it doesn't look good at all and the people I will show it to will be confused. =(
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2 Replies
MarkEllis
New Contributor II
If you are using the maps to convey info to others, simpler is usually better.  How about 3 maps - 2000 data, 2010 data, and a third map showing change?  If you are limited to one, combine color and hatching.  For example, show only 2010 data, graduated by color; change could be shown by hatching.  So there could be 15 symbols, 3 hatch patterns in 5 possible colors each.  Color is easy to grade, getting multiple textures to be both intuitive and easy to distinguish can be tricky.
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JohnSobetzer
Frequent Contributor
If you want to show changes in occupancy rates, why not run an overlay (e.g Identity or Union) and then use the data from that to compute the changes for each polygon and store the result in a new field in that layer, then symbolize that layer using the new field?
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