New answers tagged

0

Use the buffer tool to create your 500m buffer polygons. Then use the intersect tool with your buffer layer as the only input. The output from the tool will be all the buffers that are overlapping with attribute information for each of the polygons that can be used to link back to your original plots.


0

I am sure more elegant ways to perform this task, but I have come to a solution. This requires sp, ggplot2, and rgeos. As before, I attached the file with the point information. PlaceCoord <- SpatialPointsDataFrame(data.frame(UTM.Easting,UTM.Northing),data=data.frame(PlaceID,Name,lngYear,IDgroup),proj4string=CRS("+init=epsg:32717")) #Establish the ...


1

Here is an approach. Some example data: library(dismo) # points n <- 10 set.seed(123) xy <- cbind(runif(n, -150, 150), runif(n, -50, 50)) # polygons p1 <- rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60), c(-180,-20)) p2 <- rbind(c(-10,0), c(140,60), c(160,0), c(140,-55), c(-10,0)) p3 <- rbind(c(-125,0), c(0,60), c(40,5), c(15,-45), c(-...


0

The answer is defining the bigger buffers as disks (outside buffers around and outside the small inner ones that does not include the inside area of inner buffers), each bigger buffer will have specific inner ones and the overlaps of bigger buffers is not important. So, easily we must follow the process of buffer making from small ones to bigger ones.


0

I think the solution to what you call "buffer" is to create a MASK raster in GRASS. Then the r.neighbors analysis (and all other raster analyses) will be limited to the area covered by the mask. You would do that in GRASS by converting the polygon to a raster, and naming it MASK: v.to.rast input=<your polygon> output=MASK use=value


0

The buffer tool from the raster package lets you work with both rasters and Spatial* objects. To to create a buffer for a single point: library(raster) pt <- SpatialPointsDataFrame(data.frame(525000,9250000), data = data.frame('Pt1'), proj4string = CRS("+init=epsg:32736")) pt.buf <- buffer(pt, width = 500, ) It returns a spatial polygon: > ...


0

Solution that works if your small polygons do not overlap: arcpy.Union_analysis("small #;large #","C:/FELIX_DATA/SCRARCH/SCRATCH.gdb/UNION","ALL","#","GAPS") arcpy.SelectLayerByAttribute_management("UNION","NEW_SELECTION",""""Name" = "Name_1"""") arcpy.DeleteFeatures_management("UNION") arcpy.Dissolve_management("UNION","C:/FELIX_DATA/SCRARCH/SCRATCH.gdb/...


0

1) In Geoprocessing, use the Union tool to create a single feature class. This causes a "cookie-cutter" effect on overlapping polygons. 2) Start editing on the newly created feature class, exported from the Union. 3) Delete the desired polygons.


0

Use reasonable buffer value. The largest measure of your polygon is about 0.0007 degrees and you are shrinking it by 3.024 degrees. The result if much less than nothing. SELECT ST_AsGeoJSON(ST_Buffer(ST_GeomFromText('POLYGON((72.89994120597838 19.070245311788284,72.89981782436371 19.069915760688904,72.9002845287323 19.070001951039718,72.9003381729126 ...


2

In your case, it is not necessary to create polygon buffers for your points. The raster::extract function has a buffer argument that will do exactly what you are after. library(raster) r <- raster(ncol=36, nrow=18) r[] <- 1:ncell(r) xy <- SpatialPoints(cbind(-50, seq(-80, 80, by=20))) extract(r, xy, buffer=1000000, fun=mean) For future ...


2

Why do you want to create a point output? Do the following: add a field and calculate the length of the "fligth line" intersect the "flight line" with the "buffer polygon" dissolve the "flight line buffer polygon line" depending on the "buffer polygon" calculate the length of the "flight line buffer polygon dissolve line" devide the length of the "flight ...


2

you could also do the conversion from degrees to meters which changes depending on the coordenates , on my case NE of Spain 0.000004°=0.9 mts approx. There are on line calculators like http://msi.nga.mil/MSISiteContent/StaticFiles/Calculators/degree.html


4

Use the Raster|Rasterize|Conversion (Vector to Raster) menu. Choose an appropriate resolution for the raster you need:


1

I imagine that this might be what you are after: If so, I think you have to first break up your polylines into lines, e.g. using the 'Explode lines' processing tool. Then, applying v.buffer as you mention above might leed to success. update What I just saw is that the 'Explode lines' tool shoots a little over the target, because it explodes each ...


2

Instead of using QgsGeometryAnalyser, you could try calling the Processing function: import processing radiouses = [10.0, 13.0, 15.0] for r in radouses: shapeout = 'c:\\temp\\point_buf_%s' % r processing.runalg("qgis:fixeddistancebuffer", iface.activeLayer(), r, 99, False, shapeout )


1

I would suggest opening a bug report. In the mean time, try performing the buffer using the QGIS Geoalgorithms -> Vector geometry tools -> Fixed distance buffer in the processing toolbox, or from some other provider/plugin.


2

The solution was: Right-Click on the Layer > Save As > Change the CRS to (NC State Plane) > New Project > Project > Project Properties > On the Fly > NC State Plane > Vector > Geoprocessing Tools > Buffer > Unit = 98.424 (30 * 3.2808)


2

Try adding sr to arcpy.Polygon(polygon, sr)Here is the reason why: I sometimes see significant coordinate movement when I do not supply a Spatial Reference to an Arcpy Geometry object such as a Polygon or Polyline. Through research I've learned the default XY Resolution (significant digits) is .0001. This is correct for Projected data but much too large for ...


2

You give no indication on the size of the raster or how many buffers so the following approach may be impractical and there is a better way. Anyway here is one method: Convert your raster to a point dataset, if you use the buffer polygon as a mask you will reduce the data volume. Assuming you buffers have a unique ID (don't use FID/ObjectID - create one if ...


0

If I understad what you are trying to do, there should be more efficient ways than dealing with buffer. ST_Dwithin is recomended instead of buffer->intersects If you combine ST_Dwithin with an directional operator, you should be able to do what you want ( if I don't miss you intentions) http://postgis.net/docs/manual-2.2/reference.html#Operators


2

Use ST_Affine to make a shifted geometry; Use ST_ConvexHull on each pair (original and shifted) to create a "directional buffer".


0

So the reference work for understanding what has happened here is Understanding Coordinate Management in the Geodatabase (unfortunately, Esri broke their website this weekend, so I can't link to their site at this moment). Essentially, the fact that "projections match" is of no consequence, because a coordinate reference in ArcGIS encompasses more than just ...


0

Remove overlaps and zonal statistics will perform as expected. Extract from tool help: If the zone feature input has overlapping polygons, the zonal analysis will not be performed for each individual polygon. Since the feature input is converted to a raster, each location can only have one value. An alternative method is to process the zonal ...



Top 50 recent answers are included