Interpolation is performed in two steps, first step is calculation of fractional indices and second step is interpolation based on fractional indices.
Fractional indices are calculated by calling one of the *2Jk methods. Values are interpolated by calling the Interpolate(Single, Double, Double, Single) method with the fractional indices.
Calculating fractional indices involves various map projection calculations and can be computational expensive. The fractional indices are meant to be stored in case they are to be reused.
By setting up reprojection, using one of the SetupReprojection methods, you can specify a target projection different from the grid projection. Then interpolation point coordinates provided in the *2Jk methods (as well Xy, Proj and Geo version) are assumed to be in that target map projection, and reprojection from the target projection to the grid projection will be performed before calculating fractional indices.
public class GridInterpolatortype GridInterpolator = class end| GridInterpolator | Create a new object |
| DoInterpolate | Bool specifying whether to interpolate (true) or take the closest value (false, default) |
| Reprojector |
Reprojector used when converting between map projections.
You can use this to set datum shift parameters. When no reprojection is specified this will be null. |
| Equals | Determines whether the specified object is equal to the current object. (Inherited from Object) |
| Geo2Jk |
Convert coordinates from projection easting-northing coordinates
to fractional indices in the source grid. The fractional
indices can be used directly in the Interpolate(Single, Double, Double, Single)
method.
For a 3 x 2 element/cell based grid, (j,k) is in the range [0;3] x [0;2]. For a 3 x 2 node based grid, (j,k) is in the range [0;2] x [0;1]. |
| GetHashCode | Serves as the default hash function. (Inherited from Object) |
| GetType | Gets the Type of the current instance. (Inherited from Object) |
| Interpolate | Interpolate in the source array at relative/fractional index (jRel,kRel), using the undefinedValue as an undefined value/delete value that is not taken into account when interpolating. |
| IsInside | Check if fractional index is inside grid. |
| Proj2Jk |
Convert coordinates from projection easting-northing coordinates
to fractional indices in the source grid. The fractional
indices can be used directly in the Interpolate(Single, Double, Double, Single)
method.
For a 3 x 2 element/cell based grid, (j,k) is in the range [0;3] x [0;2]. For a 3 x 2 node based grid, (j,k) is in the range [0;2] x [0;1]. |
| SetupReprojection(Cartography) |
Enable reprojection, i.e. conversion from a target coordinate system
to the coordinate system of the grid.
The returned Reprojector object can be used for specifying datum shift parameters. The Reprojector is set up using the grid projection as the source projection and the projection provided in this method as the target projection. It must always have the convertion type Geo2Geo handling datum shifts only. |
| SetupReprojection(Reprojector, Cartography) |
Enable reprojection, i.e. conversion from a target coordinate system
to the coordinate system of the grid.
The Reprojector object is used for datum shift conversions only. The Reprojector must be set up using the grid projection as the source projection and the projection provided in this method as the target projection. It must always have the convertion type Geo2Geo, i.e. handling datum shifts only. |
| ToString | Returns a string that represents the current object. (Inherited from Object) |
| Xy2Jk |
Convert coordinates from local grid x-y coordinates
to fractional indices in the source grid. The fractional
indices can be used directly in the Interpolate(Single, Double, Double, Single)
method.
For a 3 x 2 element/cell based grid, (j,k) is in the range [0;3] x [0;2]. For a 3 x 2 node based grid, (j,k) is in the range [0;2] x [0;1]. |