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0

Well, you can do that using ogr2ogr, after exporting vectors from GRASS to shp: ogr2ogr -sql "SELECT * FROM file_in WHERE 'category' == 2 AND OGR_GEOM_AREA > 10000" file_out.shp file_in.shp file_in.shp is your data exported from GRASS file_out.shp is your filtered results. Then you can run: ogr2ogr -sql "SELECT count(OGR_GEOM_AREA) FROM file_out" ...


0

Thanks @Crhis W , I tried the angle system, and it really works! I computed the bearing for each line, coded each bearing as: NE - NW - SE - SW in another field. Then flipped it, if there was a -1 on its "one way" attribute field, and voilĂ , there you have!!. Here an example: All I need now is to know how to compare automatically. I have thought about ...


2

The other answers cover the Spatial Analyst extension. Another option is the 3D Analyst extension. You can create a TIN from your contours, then convert the TIN to a raster, before calculating the slope.


5

You first need to make a raster DEM from your contours. That requires the Spatial Analyst extension, and uses the Topo to Raster tool (Spatial Analyst | Interpolation toolbox). That elevation raster can then be used as the input for the Slope tool. Note that since this is an interpolation process, it is estimating the elevation values between the contour ...


0

In order to make a slope map you need to work with raster data. You will need to make a raster tile (ie: DEM) from your contours. With the output raster you will then be able to make a slope map.


1

Since the 1.10 version of GDAL/OGR, you can now "georeference" vectors layers (Add ability to transform vectors based on GCPs in ogr2ogr) with translations, rotations and shearing ogr2ogr -gcp 5 -135 0 0 \ -gcp 283 -135 1000 0 \ -gcp 5 278 0 1000 \ -gcp 283 278 1000 1000 \ -f "ESRI shapefile" gcppolyg2.shp gcppolyg.shp This feature ...


1

How did you do the setting them all in CRS WGS84? Using Set CRS for Layerhas definitely corrupted your data. This changes the CRS, but does not reproject the coordinates to the new CRS. So delete those layers with 6digit coordinates, and add them again. Usually the CRS information is stored in the file, and should not be altered. As mkennedy noted, they can ...


0

if you are snapping the B towards the A, you could create 5 m buffers around each A's, then you use snap with a tolerance of 60 meters.


4

I've figured out an algorithm for the grid approach using several Python tools. Rasterising and polygonising is done with rasterio, which is based on GDAL/OGR. Here are most of the imports: import rasterio import numpy as np from rasterio import features from shapely.geometry import mapping, shape from shapely.ops import cascaded_union from math import ...


3

For the Points that fall within the 65 meter radius, can't you just subtract 5 meters from A's Y coordinate and use A's X coordinate to find a Point at the 5 meter position? You can use the DA cursor to update these Point's Geometry to the 5m position.


0

If you're not limiting yourself to an arcpy solution, what you're describing sounds like fairly common practice with ArcObjects - there is a 'Buffer Snap Agent' sample here: Buffer snap agent http://resources.arcgis.com/en/help/arcobjects-net/conceptualhelp/index.html#/d/000100000334000000.htm I haven't tested it but was interested in the VB.NET logic - ...


1

How about this for an idea. If B is within the specified distance of A then create a polyline between A and B. You can then create a point any distance along that polyline. Polyline object has a method positionalongline.


1

I've put a lot of time into trying to get route-me to render vectors. In my opinion using the built in vector rendering, RMPath and markers does not scale to the amount of data needed to render a map. That doesn't mean that route-me isnt an isn't an option, you could use mapnik to do the rendering, then pass the data to route-me to render. As of now there ...


2

Do the following: add field "OldArea" to the parcels and populate with area values (Field right click - Calcualte Geometry) Perform Intersect with the Zones dataset add another field ("NewArea") and populate with areas after intersection (same way than #1) calculate the percentage = (NewArea/OldArea) * 100 in the new field



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