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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


15h
comment NDVI derived from Landsat band 3 and band 4 using QGIS raster calculator shows the different range when opening in the ArcGIS
Have you calculated statistics in ArcGIS? If you navigate to the raster in ArcCatalog, right click on it ans select calculate statistics.
1d
comment Handling mountain shadows when classifying Landsat 8
This is why at-sensor reflectance and orthorectification are important preprocessing steps.
2d
comment Fitting Time-series Values with a Gaussian Function
I am with @whuber on this one. You may "reduce noise" but at the cost of biasing the resulting distribution. I would look into nonlinear smoothing functions more common in temporal analysis such as local polynomial regression (LOWESS). If you are wanting a linear fit you can explore a mixed effects model with an ARIMA-II term.
Oct
20
comment regression model with randomForest in raster package
You are not giving us a reproducible example and it is very unclear exactly what you are asking. Have you fit a regression instance of RF? If so, on what data? It is a bad idea to fit a regression to catagorical (e.g., landcover) data. Are the rasters you are defining in the predict function actually in the model? If you provided your code and not just a screen shot of the error message the community may be able to provide some relevant advice.
Oct
16
comment How can I get a .asc file to load into QGIS?
Definitely an issues with the file. There is a large amount of information that a parser just cannot deal with. You have special characters along with repeated headers and complete changes in the data format. You need to modify the file so it has a header at the beginning of the file and then consistent columns that correspond to the columns. Each column, including the header should be separated with a comma.
Oct
16
reviewed Approve suggested edit on proj4js tag wiki
Oct
16
reviewed Approve suggested edit on proj4js tag wiki excerpt
Oct
16
revised Aggregating satellite night light data in R
added 409 characters in body
Oct
16
comment Aggregating satellite night light data in R
What this error is telling you is that you cannot have df=TRUE if fun=NULL. Why do you need a data.frame? A list is so much more efficient to operate on. Since you are running on a Mac, it is hard to say that it is a "bug". The raster package is heavily reliant on GDAL. There are major issues with GDAL and the rgdal package on Mac's. This has been a continuing issue that I have run into in labs. After wasting considerable time trouble shooting, I now have a disclaimer that students use Mac's at their own peril.
Oct
16
comment Using ASCII LiDAR data tiles which are centimeter rounded (n Z) in ArcGIS Desktop seems to round them to meters?
This is a very nice answer!
Oct
16
answered Interpolating mobile signal data
Oct
16
answered Aggregating satellite night light data in R
Oct
15
comment How to clear areas outside map in R
You need to clip the polygon. You can easily do this via "gIntersection" in the rgeos package.
Oct
14
answered How can I create an DEM from Point-Data
Oct
13
reviewed Approve suggested edit on Free radar (SAR) satellite data
Oct
13
comment Extraction of pixels from layerstacked NDVI image
I do not believe that this is a classification problem. The post states that they have a "thematic rice image" which I assume, represents a classification of rice. It sounds like this is simple a masking question.
Oct
13
comment Read ESRI shape file (polygon or polyline) in R Environment
In the future, please make some effort to search the site. This is addressed in many posts. That said, look at "readOGR" for vector and "readGDAL" for rasters using the rgdal package. The help documents are very clear with specific examples for shapefiles. The preferred alternative for rasters are "raster", "stack" or "brick" in the raster packages. There are also options using the maptools package but they do not retain projection information. One advantage of rgdal is that you have access to several additional functions associated with GDAL.
Oct
10
comment Polygon fill colour specified by column R spplot
I believe that lattice recycles the color vector based on the levels in the factor. So, col.regions=c("yellow","green") should work.
Oct
9
comment Count overlapping polygons in single shape file with R
Another approach would be the "gIntersects" function in the rgeos package.
Oct
5
comment What are the most efficient Geographic Weighted Regression packages?
GeoDa does not include a GWR model, only autocorrelation analysis and spatial regression.