This task creates a vector from the geometry of a columned ASCII file.
Example
This example opens a column-delimited ASCII file containing meteorological data for 15 weather stations. The first column contains geographic longitudes, and the second column contains latitudes. The ASCII data are converted to a vector layer, which is then displayed on top of a shaded-relief image.
e = envi()
ASCIIFile = FILEPATH('ascii.txt', $
SUBDIRECTORY = ['examples', 'data'])
ImageFile = Filepath('natural_earth_shaded_relief.jp2', $
Subdir=['data'], Root_Dir=e.Root_Dir)
Image = e.OpenRaster(ImageFile)
Task = ENVITask('ASCIIToVector')
Task.INPUT_URI = ASCIIFile
Task.LINES_TO_SKIP = 5
Task.DATA_COLUMNS = [1,2]
Task.Execute
View = e.GetView()
Layer = View.CreateLayer(Image)
Layer2 = View.CreateLayer(Task.OUTPUT_VECTOR)
View.Zoom, /FULL_EXTENT, LAYER=Layer2
Syntax
Result = ENVITask('ASCIIToVector')
Input parameters (Set, Get): COORD_SYS, DATA_COLUMNS, GEOMETRY_TYPE, INPUT_URI, LINES_TO_SKIP, OUTPUT_VECTOR_URI
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
COORD_SYS (optional)
Specify the input coordinate system of the incoming geometry.
DATA_COLUMNS (required)
Specify an integer array with the column numbers corresponding to X and Y geometry data. The X column contains longitudes or eastings. The Y column contains latitudes or northings. For example, if the third column of the ASCII file contains longitudes and the fourth column contains latitudes, set DATA_COLUMNS to [3, 4].
GEOMETRY_TYPE (optional)
Specify a string indicating the geometry type. The choices are:
- Polygon
- Polyline
- Point (default)
- Multipoint
INPUT_URI (required)
Specify the fully qualified URI to an input ASCII file that contains the geometry records.
LINES_TO_SKIP (optional)
Specify the number of lines to skip at the beginning of the ASCII file.
OUTPUT_VECTOR_URI (optional)
Specify a string with the fully qualified path and filename for OUTPUT_VECTOR.
Output Parameters
OUTPUT_VECTOR
This is a reference to the output vector.
Methods
Execute
Parameter
ParameterNames
Properties
DESCRIPTION
DISPLAY_NAME
NAME
REVISION
TAGS
Version History
See Also
ENVITask, ENVIASCIIToROI Task