The Construct TIN tool can be used to create a triangular irregular network (TIN) from a collection of vector points or the nodes in a vector polyline or polygon coverage. The user must specify the name of the input vector shapefile, the name of the field within the vector's attribute table that is used to indicate height, or optionally if the shapefile is of a z-dimension (i.e. ShapeType of PointZ, PolyLineZ, or PolygonZ) height values can be derived from the z-values. The output vector will be of a polygon ShapeType with an attribute table containing fields related to the plane associated with each triangular facet. The output fields include the entries EQ_AX, EQ_BY, EQ_CZ, and EQ_D, which together describe the parameters of the facets planar equation, such that:
Ax + By + Cz + d = 0
Additionally, the output vector's attribute table contains fields for the plane's slope gradient (steepness), slope aspect (orientation), a hillshade value, and the elevation of the central value. When the tool is complete, the resulting TIN is automatically displayed rendered with the hillshade attribute.
It is possible to use the Rasterize TIN tool to convert the vector TIN model to a raster grid.
The following is an example of a Python script that uses this tool:
wd = pluginHost.getWorkingDirectory()
# Input data has the shapefile name followed
# by the attribute, separated by a semicolon.
inputData = wd + "spotHeights.shp" + ";" + "HEIGHT"
useZValues = "false"
outputFile = wd + "TIN.shp"
args = [inputData, useZValues, outputFile]
pluginHost.runPlugin("ConstructTIN", args, False)
This is a Groovy script also using this tool:
def wd = pluginHost.getWorkingDirectory()
// Input data has the shapefile name followed
// by the attribute, separated by a semicolon.
def inputData = wd + "spotHeights.shp" + ";" + "not specified"
def useZValues = "true"
def outputFile = wd + "TIN.shp"
String[] args = [inputData, useZValues, outputFile]
pluginHost.runPlugin("ConstructTIN", args, False)