Grid functions

Grid functions are used to calculate with data items of grid (two-dimensional) domains, explicitly using the two-dimensional structure of data in a Grid, like Potential or District.

  • Dist2 - the distances in a grid towards a point data item
  • Griddist - impedance in a grid towards the nearest point in a pointset, summing the resistances of the shortest path to the nearest point
  • griddist_untiled - Griddist with untiled processing (identical result)
  • griddist_maximp - Griddist with a maximum-impedance cutoff parameter
  • griddist_maximp_untiled - griddist_maximp with untiled processing
  • griddist_zonal - Griddist with a (uint16) zone grid and a zone-boundary impedance
  • griddist_zonal_untiled, griddist_zonal_maximp, griddist_zonal_maximp_untiled - combinations of the zonal, maximum-impedance and untiled forms
  • griddist_latitude_specific - Griddist for EPSG:4326 grids: horizontal steps scale with cos(latitude)
  • griddist_untiled_latitude_specific, griddist_maximp_latitude_specific, griddist_maximp_untiled_latitude_specific - the same combinations for EPSG:4326 grids
  • griddist_zonal_latitude_specific, griddist_zonal_untiled_latitude_specific, griddist_zonal_maximp_latitude_specific, griddist_zonal_maximp_untiled_latitude_specific - zonal combinations for EPSG:4326 grids
  • griddist_maximp - griddist with maximum impedance cutoff
  • griddist_zonal - griddist with extra impedance for zone boundary crossings
  • griddist_latitude_specific - griddist with latitude-dependent cell sizes
  • Potential - a neighborhood operation to sum the values of neighbouring cells in a grid, based on a kernel
  • potentialSlow - Potential with the direct (non-FFT) reference backend; identical result
  • potential64 - Potential with the float64 FFT backend; identical result
  • potentialRaw64 - Potential with the float64 FFT backend, without the smoothing step
  • potential32, potentialRaw32 - Potential with the float32 FFT backend: half the memory, a relative error in the order of 10^-6
  • Proximity - a neighborhood operation to get the maximum value of neighbouring cells in a grid, based on a kernel
  • Diversity - the number of different occurrences in the neighbourhood of each cell in a grid
  • District - partition according to areas of adjacent (horizontal & vertical, not diagonal) grid cells with the same values
  • district_4 - is the District variant that connects cells with equal values via the 4 orthogonal neighbours
  • district_uint8, district_uint16, district_uint32, district_uint64 - District variants with a typed district domain
  • district_4_uint8, district_4_uint16, district_4_uint32, district_4_uint64 - district_4 variants with a typed district domain
  • district_8_uint8, district_8_uint16, district_8_uint32, district_8_uint64 - District_8 variants with a typed district domain
  • District_8 - partition according to areas of adjacent (horizontal & vertical & diagonal) grid cells with the same values
  • perimeter - for each occurring partition count the number of edges that cells of that partition have with other cells or the raster border
  • perimeter_weighted - same, but with provided weights for the North, East, South, and West edges
  • Raster_merge - to merge data from smaller to larger grids, e.g. to combine country grids to a European grid