Interpolation Plugin¶
The Interplation plugin can be used to generate a TIN or IDW interpolation of a point vector layer. It is very simple to handle and provides an intuitive graphical user interface for creating interpolated raster layers (See Figure_interpolation_1). The plugin requires the following parameters to be specified before running:
- Input Vector layers: Specify the input point vector layer(s) from a list of
loaded point layers. If several layers are specified, then data from all layers
is used for interpolation. Note: It is possible to insert lines or polygons as
constraints for the triangulation, by specifying either “points”, “structure
lines” or “break lines” in the Type
combobox. - Interpolation attribute: Select attribute column to be used for interpolation
or enable the
Use Z-Coordinate checkbox to use the layers
stored Z values. - Interpolation Method: Select interpolation method. This can be either ‘Triangulated Irregular Network (TIN)’ or ‘Inverse Distance Weighted (IDW)’.
- Number of columns/rows: Specify the number row and colums for the output raster file.
- Output file: Specify a name for the output raster file.
- Add result to project to load the result into the map canvas.
Figure Interpolation 1:
Interpolation Plugin 
Using the plugin¶
- Start QGIS and load a point vector layer (e.g.,
elevp.csv). - Load the Interpolation plugin in the Plugin Manager (see Section
Loading a QGIS Core Plugin) and click on the
Interpolation
icon which appears in the QGIS toolbar menu. The Interpolation plugin dialog
appears as shown in Figure_interpolation_1. - Select an input layer (e.g., elevp ) and column
(e.g.,
ELEV) for interpolation. - Select an interpolation method (e.g. ‘Triangulated Irregular Network (TIN)’),
and specify a cellsize of 5000 as well as the raster output filename (e.g.,
elevation_tin). - Click [OK].