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10h
comment voronoi / thiessen different CRS
Voronoi polygons created in spherical coordinates (such as WGS84) will be wrong because of the severe distance distortions. The same goes for Pseudo-Mercator, although to a lesser degree within small areas (because it is conformal).
10h
comment How to automatically sum up values within buffers?
Do you have access to a raster GIS, such as the Spatial Analyst extension?
10h
reviewed Approve Create polygon symbology from attribute?
10h
reviewed Approve Get dynamic params created from new ol.source.ImageWMS
10h
reviewed Reopen Grid parameter restriction of mpl_toolkits.basemap.maskoceans
2d
comment Generally accepted root mean square (RMS) error for rectifying topographic maps
@radouxju I agree: thank you for the clarification.
Feb
8
comment Building predictive maps of response variables in R
It looks like you have a change of support problem, especially if the trapping sites are of different sizes. In effect, your data represent properties of regions of relatively large spatial extent, whereas you wish to draw a map in which properties are assigned to points. Something has to give. If most of the trapping sites are approximately the same size, one work-around for this problem is to surround every grid pixel with a hypothetical trapping area of this common size (and shape) and assign the land cover proportions from the hypothetical area to the pixel.
Feb
8
comment Building predictive maps of response variables in R
Given that any well-defined trapping site is so small that it can be considered to have only one land cover type, exactly how did you define and measure "proportion of land cover types" at your sites? Did you look at the proportions within a certain distance, for instance?
Feb
7
reviewed Approve How to get the Flow or directional raster map using GRASS?
Feb
7
reviewed Reviewed Identify cities for interval 10-100 miles for landfill gas leak risk for each ladfill site?
Feb
7
reviewed No Action Needed CartoCSS: alpha blending with comp-op
Feb
7
reviewed Reopen How to automate the georeferencing of aerial photos?
Feb
7
comment How to automate the georeferencing of aerial photos?
Would the ArcGIS tool work on grayscale versions of your RBG photos? That would eliminate the problem with color differences.
Feb
7
comment Creating spatial population heat map
That's not what kriging does. You don't really think there exist positive numbers of males at every point on a map, do you? But that's what it would indicate. How to make an accurate map depends on what these data mean--that is, whether they are an exhaustive census (which seems unlikely) or samples. And if they are samples of a population, the mapping method has to depend on the methods used to select the sample locations and observe the crabs. Of course you could ignore these issues and make a contour map of your data--but you could not legitimately claim it has any meaning or accuracy.
Feb
6
comment How to group 10k points into closest pairs?
This seems to rely on luck, guesswork, and intuition. It also seems it could leave an awful lot of orphan (unpaired) points behind. Could you supply any reasons why it should work, if only approximately?
Feb
6
reviewed No Action Needed (python) distance between a point and a list of segments
Feb
6
reviewed Looks OK Adding geoserver vector wms layers in openlayers 3
Feb
6
reviewed Approve Using Python to select records by date field
Feb
5
comment Creating spatial population heat map
Could you please explain the distinction you are trying to make between "point density" and "population density"? And what kind of map are you trying to create? A point map, a choropleth map, a contour map, something else?
Feb
5
comment Filling up river corridors in a DEM
Could you elaborate on what you are trying to achieve? It's unclear what you mean by "fill," "visible," "predefined boundary polygon," and "upper edge." Of course these words are suggestive--we all know what they could mean in casual conversation--but in order to describe an algorithm or an analytical objective you need to be specific and quantitative.