digitalmaps

259 reputation

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	location	Ontario, Canada
	age	39
visits	member for	1 year, 3 months
	seen	Feb 25 at 19:32
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I mainly use the statistical programming language R to solve problems, typically of a spatial, biological, and geographical nature. I have been using R since it was S-plus (back in the late 90s). Despite this I have an unfortunate tendency to resort to the for loop, which is not exactly favoured in R practice, probably because I learned to program using Turbo Pascal version 5.5!

	259 reputation	bio	website		visits	member for	1 year, 3 months
17 badges		location	Ontario, Canada		seen	Feb 25 at 19:32

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Mar 3	awarded	Yearling
Jul 4	accepted	Correct use of the terms geographic, path, and Euclidean distance
Jul 4	comment	Correct use of the terms geographic, path, and Euclidean distance Utterly comprehensive and detailed answer! I thought that cost distance calculations were typically implemented using graph theory representations of rasters. The cost distances are, then, found as the minimum weight path through a weighted graph. While this may be a typical algorithmic solution, is the approach you imply likely to be more efficient?
May 17	comment	Open an ArcGIS layer package in open source software Very helpful. As indicated in your figure, the shapefiles I was looking for were in commonData\Data0
May 17	accepted	Open an ArcGIS layer package in open source software
May 16	asked	Open an ArcGIS layer package in open source software
Apr 30	awarded	Commentator
Apr 30	comment	How to intersect lines and polygons in R? @Simbamangu it doesn't seem that `gIntersection()` will really do what you want. If your lines, forming a grid, were polygonized, it might work, but this is probably not what you want. I suggest asking this either on StackOverflow where more spatial R folks hang out, or on the R-sig-geo list where you'll reach the architects of `rgeos` and related tools.
Apr 24	accepted	What are some examples of model-based upscaling of raster data?
Apr 22	comment	How to intersect lines and polygons in R? @Simbamangu I just used your files to run the above script, and I found that the line should be changed to: `poly <- readShapePoly("poly.shp")`. There are no files `polygon.*` in the zip you provided. It then worked for me, performing the intersection as expected. Could the error be as simple as loading the wrong shape file? (I am using `rgeos` package version 0.2-1 under R 2.14.2)
Apr 22	comment	How to intersect lines and polygons in R? It likely comes down to the format of your `Spatial*` object. Try producing a `SpatialLines` and a `SpatialPolygons` object from first principles and compare what you have there to the object you load using `readShapePoly()`. It could be something like IDs are not continuous, or hole attributes.
Apr 22	comment	How to intersect lines and polygons in R? I have found `rgeos::gIntersection()` to also be quite fussy about the nature of the `Spatial*` object you pass it. I have also solved very cryptic error messages from this function by using the `byid=TRUE` parameter. Not sure if this will work in your case.
Apr 12	revised	What are some examples of model-based upscaling of raster data? added 81 characters in body
Apr 12	revised	What are some examples of model-based upscaling of raster data? added 627 characters in body
Apr 12	comment	What are some examples of model-based upscaling of raster data? Agreed that the resulting product wouldn't be a raster if cells weren't regular. However, it is still a data structure that could, in theory, be of value. Thanks for your good coverage of this topic from a GIS perspective. I suspect that what I am after may be not really be a GIS question, per se, but rather one of spatial analysis in general.
Apr 11	accepted	Appropriate distance metric for spatial clustering of geographic coordinates
Apr 10	revised	What are some examples of model-based upscaling of raster data? added 86 characters in body
Apr 10	comment	Looking for R-compatible geospatial datasets You can use the GADM data gadm.org in R. You can download vector data directly in R format.
Apr 10	asked	What are some examples of model-based upscaling of raster data?
Apr 10	awarded	Self-Learner