Map of the Different Gaps Statuses in Missoula County

Maps of Overlapping Polygons within GAP Status

Here is the current issue. When I plotted the different GAP statuses,I noticed there was significant overlap within specific statuses. As a result, I ran an exploratory analysis where I calculated which polygons had overlaps with other polygons by each GAP status. As you can see, status 1 does not have any overlaps. GAP statuses 2 and 4 have very small overlaps. Lastly, overlaps are a prevalent issue in GAP status 3. Now, because of this, we have to make a decision on how we handle these overlaps because it lends itself to double counting similarly to how the double counting in the GAP statues occurs.. I’ve tried to find why these overlaps occur but I cannot find a concrete answer online. I currently have two broad ideas.

  1. We verify if its a category issue. Like we previously discussed, when sub-setting the protected area layer we had to choose a list of categories that were important for analysis. I am currently looking into the data on this to see if we have redundant categories or if there is a conflict there. This might lead to a revisiting of these categories.

  2. We don’t eliminate the overlapping polygon. Instead we erase the overlapping segments of each polygon. This will introduce some bias into the analysis by changing some measurements (i.e., polygons of x national forest might go from 400 km^2 to 200 km^2) but the polygons for extracting the cell phone data will remain unchanged.

I have already written a script to “erase” polygons that are overlapping across GAP statuses but now we must handle overlap within GAP status categories.

Appendix: Retained Categories

Table of all categories within the PAD US data. Ones in green were retained for analysis.

Class Number Property Type
1 Military Land
2 Native American Land Area
3 Research or Educational Area
4 National Public Lands
5 Recreation Management Area
6 Resource Management Area
7 National Forest
8 National Grassland
9 Historic or Cultural Area
10 National Monument
11 National Park
12 National Recreation Area
13 National Wildlife Refuge
14 Federal Other or Unknown
15 Local Park
16 Local Recreation Area
17 State Park
18 Local Conservation Area
19 Private Conservation
20 Not Designated
21 State Conservation Area
22 State Recreation Area
23 State Resource Management Area
24 State Wilderness
25 Conservation Area
26 Local Other or Unknown
27 Local Resource Management Area
28 Private Agricultural
29 Private Recreation or Education
30 Unknown
31 Private Other or Unknown
32 Area of Critical Environmental Concern
33 Inventoried Roadless Area
34 Wilderness Study Area
35 National Scenic or Historic Trail
36 National Scenic, Botanical or Volcanic Area
37 Research Natural Area
38 Special Designation Area
39 Wilderness Area
40 Wild and Scenic River
41 Other Easement
42 Conservation Easement
43 Recreation or Education Easement
44 Historic or Cultural Easement
45 Agricultural Easement
46 Unknown Easement
47 Forest Stewardship Easement
48 Ranch Easement