Create Polygon PLY File

Use the POLYDEF GX to create a new polygon file or add polygons to an existing polygon file. Polygon files are used in a number of dialogs for purposes such as masking and area selections.

The option is available with the following extensions and menus:

• Database Tools > Window Data > Create Polygon PLY File

• Map Tools > CAD Tools > Create Polygon PLY File

• Airborne QC > Generate Flight Path Plan > Create Boundary File > Create Polygon PLY File in the Airborne Quality Control extension

• Geochem Analysis > Classify by Region > Create Polygon Mask in the Geochemistry extension

Create Polygon PLY File dialog options

Polygon file name (.ply)	Specify the name of the polygon file to create or append to.
Inclusive or Exclusive?	Exclusive polygons define areas to be excluded from the mask, which can be useful for defining holes in the area. Exclusive polygons are not supported on their own; you must always put them inside a larger inclusive polygon to obtain consistent results.
[New File]	Click this button to create a new polygon file.
[Append]	Click this button to append a new polygon to the existing polygon file.

Application Notes

You will be able to define a polygon using the mouse in the currently active map window.

Use Exclusive polygons to define holes in the data.

Polygons are ASCII files with default extension .ply. A polygon file contains a list of X,Y coordinates that define one or more polygons. The file may contain any number of polygons, and each polygon may have any number of vertices. The first and last points in each polygon are assumed to connect. If the file will contain more than one polygon, each polygon must start with a line 'poly #' ('p' or 'P' in column 1). Comment lines are indicated by a '/' in column 1.

Clip polygon files may also be generated interactively by using the digitising tools in the Map Tools menu.

Example of a single polygon file:

 /
				
 / Sample single polygon file
 /----------------------------
 4325.2 8421.8
 6800 8421.8
 6850 4000
 4300 4000
 
Following is an example of a three polygon file:
 /
 / Sample three polygon file with an exclusive polygon
 /---------------------------
 poly
 4325.2 8421.8
 6800 8421.8
 6850 4000
 4300 4000
 poly
 7000 8421.8
 8000 8421.8
 8000 4000
 7000 4000
 poly
 exclusive
 7400 7000
 7800 7000
 7800 5000
 7400 5000