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bio website evansmurphy.wix.com/…
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visits member for 2 years, 9 months
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I am a senior landscape ecologist with The Nature Conservancy's, Central Science. I attempt to bring vigor from diverse fields such as landscape ecology, spatial statistics, remote sensing and applied mathematics to answer practical conservation questions. I hold Affiliate Associate Professor status at University of Wyoming and have over 65 publications in peer-reviewed journals.

My research is focused on spatial statistics in ecological applications, species distribution modeling, climate change, landscape genetics, Bayesian statistics, Lidar and spectral remote sensing and gradient modeling. I have ridden horses for 35 years and was a member of the US Equestrian team. I have also played guitar in several swing and bluegrass bands


19h
comment Estimating vegetation composition from digital images
I do not believe that there is a segmentation module in this QGIS plugin.
20h
answered Estimating vegetation composition from digital images
2d
answered can i comparing landsat 7 and landsat 8 thermal band?
Mar
26
revised Assigning RGB values from Geotiff image to LiDAR data, using R
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Mar
26
comment Assigning RGB values from Geotiff image to LiDAR data, using R
Although this can be done in R using the code I provided in my answer. @Andre Sliva provided a much more tractable answer here.
Mar
24
revised Assigning RGB values from Geotiff image to LiDAR data, using R
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Mar
24
answered Assigning RGB values from Geotiff image to LiDAR data, using R
Mar
14
comment Convert line shapefile to raster, value=total length of lines within cell
Yes, but "rp" is the object that is being rasterized which it the intersection of polygons and points.
Mar
13
revised is there an operation for measuring constancy (ecology)
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Mar
13
revised is there an operation for measuring constancy (ecology)
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Mar
13
answered is there an operation for measuring constancy (ecology)
Mar
13
comment Transforming aspect values in order to use them in multiple regression models
The variable is no longer circular.
Mar
12
revised How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?
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Mar
12
revised How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?
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Mar
12
answered How calculate pixel by pixel the mode (statistic) of multiple rasters (geotiff)?
Mar
12
comment How to perform a non-linear regression pixel by pixel?
Has anybody on this thread looked at help for the raster "calc" function, which provides an example for exactly this problem (see "some regression examples" at end of examples)? There are still tractability issues related to this approach that need to be considered so, yes the model does matter. In the temporal example that you indicate, you do not have a serial autocorrelation term in the model which, in a n=365 stack would certainly represent a pseudo-replication issue.
Mar
12
comment Assigning RGB values from Geotiff image to LiDAR data, using R
A 3D plot of what? In exact terms a 3D plot is X,Y,Z. The x,y represent your spatial domain extent and z would be elevation. How do the RGB values come into play? Do you want the points color-coded by the RGB values as well. So, apparently not so simple a question. Detailed questions yield more specific answers.
Mar
12
comment Assigning RGB values from Geotiff image to LiDAR data, using R
You are confusing terms in a way that is making the question, and your code, nonsensical. Polygons represent discrete areas whereas points are explicit x,y locations. It looks like you are reading a point feature class and not polygon. If this is the case, you do not want "fun=mean" in the extract function. I would also point out that R is not the ideal software for 3D plots of large point clouds. Additional, your intent is fine for visualization but due to parallax issues of 2D projected onto 3D data, you cannot use this analytically.
Mar
11
comment Transforming aspect values in order to use them in multiple regression models
Sorry, no I meant the "linear aspect" tool. I modified my answer to reflect this a provide the methodology to do this outside of my toolbox.
Mar
11
revised Transforming aspect values in order to use them in multiple regression models
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