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bcgov / bc-bear-dens

Data management and analysis for the LUPCE Bear Dens project
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Add year buffer to road retirement dates #13

Closed popovs closed 4 days ago

popovs commented 6 days ago

Currently, for all road GIS verifications, road sections are being filtered by award date and retirement date. However, roads are often still driveable many years after being retired on paper. Add 5, 10, and 15 year 'buffers' to the retirement date of the road to include them in the distance to road calculations and see which ones line up best with field estimates of distance to road. Mary is guessing 10 years is our best bet.

popovs commented 5 days ago

Results with buffer years added around retirement

0 5 10 15
raw 50% 52% 52% 52%
legacy v 76% 76% 76% 76%

So it seems the error seems to stabilize around 5 years.

popovs commented 4 days ago

Investigating the 25% that don't line up with historical verifications and 48% that don't line up with raw value. The majority are < 100 m difference.

VDIFF Image

> summary(investigate$dist_road_VDIFF)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
   6.00   13.00   23.00   60.28   63.00  940.00

RAWDIFF Image

> summary(investigate$dist_road_RAWDIFF)
   Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
   4.00   14.25   36.00  140.61  135.75 1943.00
popovs commented 4 days ago

Investigated dens where the discrepancy between new GIS verification and legacy verification is >25m. N = 29.

Investigated dens where the discrepancy between new GIS verification and raw value is > 25m. N = 65, 23 of which were the ones that also tripped the legacy verification.

Out of the discrepancies, errors in the field data ("Field error") + mismatches between which roads to measure to between field & verification data ("Unclear road data") account for the greatest share. After that, it's almost all caused by issues in the GIS road data that can't really be fixed by filtering - e.g. ghost roads that don't exist, presumably awarded but never built, and overgrown roads with no/incorrect retirement date.

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