RasterGeometry.GetCellValue Methods
Gets the value at the given position inside the raster.
Overload List
| Name | Description | |
|---|---|---|
| Public method | GetCellValue(Point position) | Gets the value at the given position inside the raster, using bilinear interpolation if the raster is continuous. |
| Public method | GetCellValue(Point position, RasterFilter rasterFilter) | Gets the value at the given position inside the raster, using a given interpolation method. |
GetCellValue(Point position)
Gets the value at the given position inside the raster, using bilinear interpolation if the raster is continuous.Syntax
public System.Int32 GetCellValue (
Point position
)Parameters
A position inside the bounding rectangle of the geometry.
Return Value
The value at the given position.
Remarks
If the associated Raster is continuous, this method will use bilinear interpolation, otherwise nearest-neighbor lookup. There is another variant of this method that lets you choose explicitly between nearest-neighbor lookup and bilinear and bicubic interpolation.
Undefined values in the raster are handled correctly during interpolation. If all cells surrounding position are undefined, the undefined value will be returned. If only some of the cells are undefined, the return value will be interpolated from the remaining values.
If the raster contains float values, the returned value will be rounded to the nearest integer. If the raster contains RGB or RGBA values, the returned value can be converted to a color with the Raster.CellValueToColor method.
If position is outside the bounds of the raster, the undefined value of the raster will be returned, or, if the raster doesn't have one, the smallest representable 32-bit integer, −2147483648.
GetCellValue(Point position, RasterFilter rasterFilter)
Gets the value at the given position inside the raster, using a given interpolation method.Syntax
public System.Int32 GetCellValue (
Point position,
RasterFilter rasterFilter
)Parameters
A position inside the bounding rectangle of the geometry.
The interpolation method: either nearest-neighbor, bilinear or bicubic.
Return Value
The value at the given position.
Remarks
Regardless of whether the associated Raster is tagged as continuous, this variant of the method will use either nearest-neighbor lookup or bilinear or bicubic interpolation, depending on the given rasterFilter. Note, though, that if the raster really is not continuous, for example if the raster values represent discrete terrain types, then only nearest-neighbor lookup makes sense.
Undefined values in the raster are handled correctly during interpolation. The interpolated value will be a weighted sum of the values for the 4 or 16 cell centers nearest the position. Bilinear interpolation uses 4 cells and bicubic uses 16. The sum of the weights for all 4 or 16 cells is 1.0, but cells that are undefined or outside the raster bounds will be ignored, so the sum of the used weights can be less than 1.0. To get a result from bilinear interpolation, it is enough if the sum of the used weights is positive (meaning at least one of the 4 cells is defined); if it is zero, the undefined value will be returned. To get a result from bicubic interpolation, the sum of the used weights must be at least 0.25.
If the raster contains float values, the returned value will be rounded to the nearest integer. If the raster contains RGB or RGBA values, the returned value can be converted to a color with the Raster.CellValueToColor method, but note that an attempt to use bicubic interpolation on RGB and RGBA rasters will throw an exception, since that is not supported.
If position is outside the bounds of the raster, the undefined value of the raster will be returned, or, if the raster doesn't have one, the smallest representable 32-bit integer, −2147483648.
Platforms
Windows, Linux, Android