Dear members of the list,
I am writing to seek advice regarding minimum mapping units (MMU) and
the geographic fit of different data sources. Currently, I am working on
a habitat availability map that I develop for my study site )Sierra de
Portuguesa - Venezuela Andes), based on the needs of the Andean bear
(/Tremarctos ornatus/). I chose a MMU of 1hectare for the output and
the Kappa analysis yield 69% accuracy for the overall map and 82% for
Andean bear habitat. Using this map I have estimated area for habitat
available, an evaluated the effects of different edge depths and
fragmentation scenarios.
I would now like to run an analysis to evaluate factors involved on
habitat prevalence such as rivers, roads, distance to villages etc. The
issue I have here is that the shift between the satellite images and the
topographic maps that provide these data is about 100-200m and thus the
MMU would at most has to be 2 hectares. With this MMU, the kappa for the
overall map is about 54% and the accuracy for the habitat available is
reduced as well regarding commission error. Thus, I was wondering if I
could run these two analysis with different MMU, in order to take the
full advantage of a higher accuracy in the estimation of habitat extent,
it would be a shame to loose accuracy given possible errors introduced
by hard copy maps.
I would really appreciate any advice on this subject,
S
Shaenandhoa García Rangel
PhD Candidate
Wildlife Research Group
University of Cambridge
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