Sticks and LCPs inexplicably dropped in final output (step 5)

[Arne Loth]

I have just run Linkage Mapper to connect a total of 1471 individual points (species records). No maximum distance cutoff or other criteria for excluding links were specified. Looking at the final output (output folder, link_maps.gdb), the sticks and LCPs have been separated into active and inactive links in a way that doesn't make sense to me. Species records in close vicinity to each other are suddenly no longer connected, while links over significantly longer Euclidian distances are included. 

The output 'lcpLines_s5' in the run_history folder, link_maps.gdb makes much more sense to me and I don't understand what happened when these links were separated for the final output as I have given no restricting criteria. For reference, the following settings were chosen when running the model:

Model Inputs

Core Area Feature Class: A point shapefile containing 1471 records

Core Area Field Name: A unique identifier (starting at 1) added to the file's attribute table

Resistance Raster: An inversion of habitat suitability (between 0 and 100) with roads added as an additional barrier (between 0 and 100), mosaicked together into a single resistance raster with values between 10 and 181 

Step 2

Cost-Weighted & Euclidian for Network Adjacency Method (perhaps this is the problem - should it have been 'connect ALL core area pairs within maximum distance cutoff'?)

Core Area Distances Text File generated via Conefor Inputs

Step 3

Drop Corridors that Intersect Core Areas selected 

Step 4

Not selected

Additional Options

None selected

I attach the following screenshots to illustrate the issue: 

1_run_history_LCPmap: the lcp lines as showing in the run_history folder (before being separated into active and inactive links)

2_output_inactiveLCPs: The inactive lcp lines from the final output folder (this is the bit I don't understand)

3_output_activeLCPs: The active lcp lines from the final output folder

4_allLCPs_cwd: all lcp lines (both active and inactive) on top of the final cwd raster (stretched color ramp from blue (low) to red (high), showing that they all are all within the lowest range of the cwd raster so differences in cost-weighted distance cannot really account for the dropped links. 

Any help/explanations about the different outputs and what they mean would be massively appreciated. I am a relative novice to GIS, and an absolute novice to any kind of species modelling and have kind of been dropped into the deep end with this exercise. Thank you very much!

Arne 

[Brad McRae]

Hi Arne,

If you click on the inactive links, it should give you a code telling
you why they were dropped. Along with that, if you can send me your
log file (directly to mc...@circuitscape.org) that would be helpful.

Brad

> --
> You received this message because you are subscribed to the Google Groups
> "Linkage Mapper" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to linkage-mappe...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.