Create a new column in a table of a cellular layer,
filling it with the result of a spatial operation, which can also involve
some attribute.
object |
Object of class aRTtable . |
newatt |
The name of the new column. |
target |
An aRTraster or aRTtheme object. |
strategy |
The way to calculate the attribute of each cell:
- average: Average of an attribute of the objects that have some intersection with the cell, without taking into account their geometric properties.
- stdev: Standard deviation of an attribute of the objects that have some intersection with the cell, without taking into account their geometric properties.
- sum: Sum of an attribute of the objects that have some intersection with the cell, without taking into account their geometric properties.
- minimum: Minimum value of an attribute among the objects that have some intersection with the cell, without taking into account their geometric properties.
- maximum: Maximum value of an attribute among the objects that have some intersection with the cell, without taking into account their geometric properties.
- majority: More common value in the objects that have some intersection with the cell, without taking into account their geometric properties.
- distance: Distance to the nearest object of a chosen geometry (requires argument geometry).
- xdistance: Approximated distance to the nearest object of a chosen geometry (requires arguments geometry and dist).
- count: Number of objects that have some overlay with the cell (requires argument geometry).
- presence: Boolean value pointing out whether some object has an overlay with the cell.
- area: Total area of overlay between the cell and the layer of polygons.
- length: Total length of overlay between the cell and the layer of lines.
- averagewba: Average weighted by area, based on the proportion of the intersection area. Useful when you want to distribute atributes that represent averages, such as per capita income.
- sumwba: Sum weighted by area, based on the proportion of the intersection area. Useful when you want to preserve the total amount in both layers, such as population size.
- percentage: Percentages of each class of a raster data. It creates one attribute for each class of the raster.
|
geometry |
The geometry to compute the attribute. One of "point", "polygon", "line", "raster". |
att |
The atribute used to compute the new column. It is only required when the strategy uses an attribute (such as average, sum, etc.) |
proportion |
Whether the calculation will be based on the intersection area, or the weights are equal for each object whth some overlap. |
itime |
The initial time (for temporal tables). |
ftime |
The final time (for temporal tables). |
dist |
The maximum error when calculating the distance. |