Topic:
How to exclude null values from grid read into MapView.

Description:
User exported grid from Zmap (Zycor mapping application) and wants to read into
MapView without null points. MapView automatically excludes -0.1000000E+31 null
values but anything other than that value will have to be edited.

Grid file must be in MapView format which is described in on-line documentation.
Geonet > IESX > Help > Version 10.x > Help on IESX Applications > Surface
Modeling > pg. 226. 

Solution:
Read in grid and in Save/Update convert grid to xyz, then use Histogram Edit
Points in Edit Points to delete null values.

1.) Select > Read Grid > Select external file, yes to confirm.

2.) Save/Update > Convert > Convert Grid to XYZ Points.
    - Type in name, title(optional), EXIT.

3.) Up-arrow > Edit > Edit Points > Histogram Edit Points.
    - Select range of null values to delete with mb1, EXIT. 
    - Up-arrow.
    - Type in name Save Data Point Edit, title(optional).
    - Toggle Save Points to YES, EXIT.

4.) Select contour icon to display grid. 

Or use the explicit option in Edit > Grid Contour to specify range of data to
display for grid. For display purposes only, does not alter the data.

1.) Select > Read Grid > Select external file, yes to confirm.

2.) Edit > Grid Contour.
   - Type in range to display for Explicit Grid Color Minimum and Maximum.
   - Toggle Grid Range Coloring to Explicit.
   - Toggle Beyond Range Coloring to Last Color or None (transparent), EXIT.





Last Modified on: 04-DEC-98