Topic:
Basemap places grids incorrectly when map projection changes.

Description:
Large regional grids are genereated in a UTM15 project.  After, the grids are
exported (through ASCII Save and GAL Load) into another project in UTM16.  The
grids are now placed in the wrong location on the map in the UTM16 project.  The
offset distance between the correct spot and its misplaced spot can be many
miles on a regional map that covers the entire Gulf area. 

Solution:
Basemap does not handle projection change properly for grid posting.  The
binset is translated from UTM15 to UTM16 without considering the binset
rotation associated with the zone change.  

In contrast, CPS-3 handles the projection change properly.  The current workaround is to let CPS-3 handle all grid exports, imports and projection
changes before moving the grids into the GeoFrame database for Basemap display.


WORKAROUND:

1) Export grids in CPS-3 from the UTM15 project.
   In CPS-3 Main Module, File > Export > ASCII > Grid, provide an export file
   name, select input data set for the grid, and select "CPS-3" as export file
   type in Assign input/output parameters window

2) Import grids in CPS-3 from the UTM16 project.
   In CPS-3 Main Module, File > Import > ASCII > Grid, select the input file,
   create a new output set with its storage set to CPS-3, and verify the file
   type to be "CPS-3".

3) Display the imported data set in a UTM16 modeling and display environment,
   and verify the location of the grid.  Create and/or expand the modeling
   environment if it's necessary.

4)  Run single surface operation B = A*1 to send the grid to the GeoFrame
    database.
    In CPS-3 Main Module, Operations > Surface > Single surface > B = A*a,
    create a new data set for B with the storage set to GeoFrame, set a = 1.

The grid is now ready for Basemap display.


RESOLUTION:  Pending




Last Modified on: 04-APR-00