DataSet.GetValueAt Methods
Gets the integer value from a raster cell at the specified position.
Overload List
| Name | Description | |
|---|---|---|
| Public method | GetValueAt(Point point) | Gets the integer value from a raster cell at the specified position, using bilinear interpolation if the dataset is continuous. |
| Public method | GetValueAt(Point point, RasterFilter rasterFilter) | Gets the integer value from a raster cell at the specified position, using a given interpolation method. |
GetValueAt(Point point)
Gets the integer value from a raster cell at the specified position, using bilinear interpolation if the dataset is continuous.Syntax
public System.Int32 GetValueAt (
Point point
)Parameters
The position, expressed in the coordinate reference system of the dataset, to get a value at.
Return Value
The value at the specified position.
Remarks
This method locates a raster covering point, and retrieves the cell value at point from the raster. If several rasters cover the point, then the highest well-defined cell value at the point is returned. If no raster is found that covers the point, or if the cells surrounding point in all found rasters are undefined, an exception will be thrown.
The lookup method will be either nearest-neighbor or bilinear interpolation, depending on whether the dataset is continuous. The bilinear interpolation will be used only for each individual raster, so it will be imperfect near data tile boundaries. See also the other variant of this method, and the basic RasterGeometry.GetCellValue method, for more details about interpolation.
If the raster contains RGB or RGBA values, the returned value can be converted to a color with the Raster.CellValueToColor method.
Example
// Get the integer value at Gothenburg
public static int GetValueAtGothenburg(DataSet dataSet)
{
// The center coordinates of Gothenburg in Wgs8LongLat
Point gothenburgCenter = new Point(11.974560, 57.708870);
// Project the center coordinates of Gothenburg to the Crs of the DataSet
gothenburgCenter = dataSet.Crs.ProjectFromLongLat(gothenburgCenter);
// Get the integer value at Gothenburg center and return it.
// If no raster is found that covers the point, or if the cells
// surrounding point in all found rasters are undefined,
// an exception will be thrown.
return dataSet.GetValueAt(gothenburgCenter);
}
GetValueAt(Point point, RasterFilter rasterFilter)
Gets the integer value from a raster cell at the specified position, using a given interpolation method.Syntax
public System.Int32 GetValueAt (
Point point,
RasterFilter rasterFilter
)Parameters
The position, expressed in the coordinate reference system of the dataset, to get a value at.
The interpolation method: either nearest-neighbor, bilinear or bicubic.
Return Value
The value at the specified position.
Remarks
This method locates a raster covering point, and retrieves the cell value at point from the raster. If several rasters cover the point, then the highest well-defined cell value at the point is returned. If no raster is found that covers the point, or if the cells surrounding point in all found rasters are undefined, an exception will be thrown.
The lookup method will be either nearest-neighbor or bilinear or bicubic interpolation, depending on the given rasterFilter, but note that interpolation makes sense only if the dataset is continuous. The bilinear interpolation will be used only for each individual raster, so it will be imperfect near data tile boundaries, but with bicubic interpolation, rasters with the same resolution and Crs will be merged first.
See also the other variant of this method, and the basic RasterGeometry.GetCellValue method, for more details about interpolation.
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 or RGBA rasters will throw an exception, since that is not supported.
Example
// Get the integer value at Gothenburg, using bicubic interpolation.
public static int GetValueAtGothenburgBicubic(DataSet dataSet)
{
// The center coordinates of Gothenburg in Wgs8LongLat
Point gothenburgCenter = new Point(11.974560, 57.708870);
// Project the center coordinates of Gothenburg to the Crs of the DataSet
gothenburgCenter = dataSet.Crs.ProjectFromLongLat(gothenburgCenter);
// Get the integer value at Gothenburg center and return it.
// If no raster is found that covers the point, or if the cells
// surrounding point in all found rasters are undefined,
// an exception will be thrown.
return dataSet.GetValueAt(gothenburgCenter, RasterFilter.Bicubic);
}
Platforms
Windows, Linux, Android