Create a polygon (*.PLY) from a shapefile (*.SHP)

In Target and Oasis montaj, sometimes you need to create a polygon file for windowing (i.e. windowing a grid to a polygon to make a new smaller grid) or masking (i.e. applying to mask to a database channel, or hiding a map group outside a polygon boundary). 

The first step is creating the polygon *.ply file.  If you are starting with an ESRI Shapefile, [you can import the Shapefile to a map, and use Create PLY File from Map Group. However, if the Shapefile contains polylines, rather than closed polygons, or if there are many items in the map group and editing would be required to isolate the polygons] then you can “blow up” a polygon shapefile when you import it to a Geosoft database.  This means that you will have a point for every polygon vertex or node, instead of just a record for the centre of the polygon [or polyline]. 

First, import the Shapefile to a new database using Database > Import > ArcView Shapefile(s).  In the ArcView Shape File Import dialog, set Import data to to "New database with shape database(s)".  When the import is complete, you will see a new {filename}_Shapes.gdb, where each polygon will be stored in a separate line in the database.

[To create the *.PLY file, export to an XYZ file and change the line references to poly tags:

poly 1
-17338.70    52620.96
-10705.64   -13104.83
-13508.06   -12096.77
-31552.41    53427.41

And remember to add the coordinate system information if you are working in multiple coordinate systems.]

Comments

[Johnetta]

Boy that rlelay helps me the heck out.

[Natalie Green]

Your PLY file appears to be formatted correctly, and you should be able to mask a GDB containing line data. A few things to check:
- Make sure that your lines are 'selected' (they will have a small checkmark in the Line Name cell).
- You may also want to verify that the data in the GDB overlaps with the PLY and that there is not a location error. Create a new map and add a line plot, then draw the ply file on the map as well.
- Note also that when you plot your line path, you may need to fill in a value for the Break on Gap option so that the line won’t draw across the gaps in the data.

[Ganaa1221]

I masked the GDB by a PLY file. But unfortunately it doesn't work. Is it possible to mask line GDB?

/#CoordinateSystem="WGS 84 / UTM zone 49N"
/#Datum="WGS 84",6378137,0.0818191908426215,0
/#Projection="Transverse Mercator",0,93,0.9996,500000,0
/#Units=m,1
/#LocalDatum="WGS 84",0,0,0,0,0,0,0
poly 1
420956.5200000000 4964922.4700000000
460478.2700000000 4964557.7000000000
460251.1200000000 4927530.7500000000
420502.1700000000 4927895.4600000000

Is there anything wrong with my PLY file?

[Natalie Green]

Thank you for your question. I have added some details above which I hope will answer your question and identify alternative approaches.

Importing to a Shape Database is also very handy if you have contours but would like to make a topography or DEM grid.

[Ian]

What s the next step to turn the gdb's into a ply.