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r:r-gis:rastervector

3-Raster-Vector Operations

Extract values for shapes(e.g SpatialPointDataFrame)

Wget raster values for overlaying vector data

  extract(rasterLayer,shapeLayer,df=TRUE)

#or to return only the e.g. mean values of e.g. overlaying polygons (identical to zonal statistics but works with vector data as zone features)

extract(rasterLayer,shapeLayer,fun=mean,df=TRUE)

vector to raster/ rasterize

  #set the values of a raster with the desired extent and resolution ("baseraster")
  #to NA:
  values(baseraster)=NA
  #...Then update this emty raster with the shape information:
  rasterize(shapeLayer,baseraster)

If a table is to rasterize use the following code:

  rasterize(cbind(x_coordinates,y_coordinates),baseraster,field=Z)

With Z is the value which the raster cells should have.

raster to polygons

  rasterToPolygons(rasterLayer)

raster to points

 rasterToPoints(RasterLayer,spatial=TRUE)

Euclidean distance

#distance from a point to all cells of a RasterLayer.
values(rasterLayer)=NA
distanceFromPoints(rasterLayer, SpatialPoint) 

If the distance is to be calculated from a raster object, see euclidean_distance in the chapter 1-Raster Operations. This function might also be useful for vector or line features: convert them to a raster and then use this function.

zonal statistics

  zonal(rasterLayer, ZoneRaster, 'mean')

Hanna Meyer

r/r-gis/rastervector.txt · Last modified: 2018/12/23 19:46 (external edit)