FilterVector Task

This task creates a new shapefile containing only vector records that fall within specified minimum and/or maximum values.

Example

; Start the application

e = ENVI()

; Open an input raster

File = Filepath('qb_boulder_msi', ROOT_DIR=e.Root_Dir, $

SUBDIRECTORY=['data'])

Raster = e.OpenRaster(File)

; Open an input vector

VectorFile = Filepath('qb_boulder_msi_vectors.shp', $

ROOT_DIR=e.Root_Dir, SUBDIRECTORY=['data'])

Vector = e.OpenVector(VectorFile)

; Get the task from the catalog of ENVITasks

Task = ENVITask('FilterVector')

; Select task inputs

Task.INPUT_VECTOR = Vector

Task.MINIMUM_VALUE = 10000

Task.MAXIMUM_VALUE = 50000

; Run the task

Task.Execute

; Add the output to the Data Manager

e.Data.Add, Task.OUTPUT_VECTOR

; Display the resulting vector

; over the raster layer

View = e.GetView()

Layer1 = View.CreateLayer(Raster)

Layer2 = View.CreateLayer(Vector)

Layer3 = View.CreateLayer(Task.OUTPUT_VECTOR)

Syntax

Result = ENVITask('FilterVector')

Input parameters (Set, Get): INPUT_VECTOR, MAXIMUM_VALUE, MINIMUM_VALUE, OUTPUT_VECTOR_URI, UNITS

Output parameters (Get only): OUTPUT_VECTOR

Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.

Input Parameters

INPUT_VECTOR (required)

Specify an input polyline or polygon ENVIVector.

MAXIMUM_VALUE (optional)

Specify the maximum area (for polygons) or length (for polylines) to consider. Values greater than the maximum will be discarded in the output shapefile. The units depend on the coordinate system of the input vector; however, you can override these units by specifying the UNITS parameter.

MINIMUM_VALUE (optional)

Specify the minimum area (for polygons) or length (for polylines) to consider. Values less than the minimum will be discarded in the output shapefile. The units depend on the coordinate system of the input vector; however, you can override these units by specifying the UNITS parameter.

OUTPUT_VECTOR_URI (optional)

Specify a string with the fully qualified path and filename for OUTPUT_VECTOR.

UNITS (optional)

Specify a string with the units of the minimum and maximum values. The choices are Meters, Kilometers, Feet, US Survey Feet, Yards, Miles, and Nautical Miles.

If you do not specify UNITS, be sure to specify the MINIMUM_VALUE and MAXIMUM_VALUE in the same units of the INPUT_VECTOR.