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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


1d
comment Calculate mean elevation over a region
You missed the critical step of extracting the "pixel" values to the fishnet points. A focal approach is really the most computational efficient way to accomplish your task.
1d
comment Calculating Slope, Flow Accumulation and Topographic Wetness Index (TWI) using ArcGIS for Desktop?
You need to provide a reproducible example so we can see what you are doing. A summary of results do not mean much if we cannot see what may have gone wrong in your analysis. We do not even know what you mean by TWI (equation?). There are many interpretations and deviations of topographic wetness indexes.
1d
comment Calculating Slope, Flow Accumulation and Topographic Wetness Index (TWI) using ArcGIS for Desktop?
Did you take time to search the site???
1d
comment Computing Shannon-Weiner biodiversity index using QGis
I echo @Curlew, there are functions in R to calculate diversity metrics. All you are talking about is aggregating the metric by group. To do this just assign your polygon IDS to the species observations and pass the data to vegan::diversity using tapply. This will give you diversity by group.
1d
answered How to add lables/etc with eia shapefiles in R?
1d
comment Difference between raster subsets as defined by another raster
Your approach is not memory safe and your are correct, a t-test is not a robust solution. When working with large data it is often helpful to think in terms of sampling approaches. Multiple realizations of a random field can be very informative.
1d
answered Difference between raster subsets as defined by another raster
2d
revised Distance to nearest point for every point same SpatialPointsDataFrame in R
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2d
answered Distance to nearest point for every point same SpatialPointsDataFrame in R
2d
comment How to calculate RMSE, skewness, and kurtosis of raster image?
To calculate skewness and kurtosis you need a distribution which, you will not have with two observations (when directly comparing two rasters). The rule of large numbers comes into play with the distribution of the entire raster, likely converging on normal. You may want to explore a fuzzy numerical, moving window correlation or intensity scale approach. Take a look at this document: dropbox.com/s/ojo2lvqavz7hyaz/literature_scan_report.pdf
2d
comment Calculating distribution of points compared to raster in ArcGIS for Desktop?
Albeit, not an ArcGIS solution, This was just addressed recently: gis.stackexchange.com/questions/131953/…
2d
comment Finding correlation between point location and raster value
Two approaches you could take would be: 1) a binominal model, in much the same way you would implement a species distribution model, with randomized null's or 2) a point pattern analysis, where you would test if your observed spatial process is significant from random. It would be easy to expand this type of analysis into a formalized Poisson point process model.
Jan
27
reviewed Approve Python output for batch “FeatureToRaster” in ArcPy
Jan
27
revised Finding correlation between point location and raster value
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Jan
27
comment Finding correlation between point location and raster value
@whuber, I completely agree! Probabilistically, the sample bias is not accounted for, particularly in my "skewed" example. Even a nonparametric test (e.g., Kolmogorov-Smirnov) will miss spatial bias underlying the sample. I just wanted to distill this question to its simplest form and provide some exploratory analysis approaches. However, this is more than what most graduate students do in exploratory analysis. Missing spatial process, sample variation and bias are common reasons that students end up in my office, often after they have collected their data.
Jan
27
revised Finding correlation between point location and raster value
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Jan
27
revised Finding correlation between point location and raster value
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Jan
27
answered Finding correlation between point location and raster value
Jan
27
comment Add a point shapefile layer to a polygon shapefile window in R
If yo just want to remove duplicate points and do not want to apply a condition (e.g., mean) you can use zerodist. Points <- Points[-zerodist(Points)[,1],]
Jan
27
comment Difference between raster subsets as defined by another raster
The data is categorical, making a correlation erronious. You want an ANOVA, t-test, which is not available in ArcGIS. Try a statistical software. You can likely do this in Excel as well, but I would not recommend it.