Pitney Bowes MapInfo Vertical Mapper - Manual (Page 126)

Understanding Grid Queries
124
Vertical Mapper 3.7
The Operator list enables you to choose the appropriate operator for the query. The choices
available vary depending upon whether the grid is numeric or character-based. In both cases, you
can also choose “Any Value” or “Null Value”.
The Value box enables you to enter a user-defined value. If the query is being created for a
character-based grid, this box becomes a list because there are only a specific number of unique
classes in any .grc file.
The Z-Min: and Z-Max: boxes display the z-value range of any numeric grid file.
You build the query expression in the Where box of the Enter Query Conditions dialog box. By
default, individual query clauses are separated with an “AND” Boolean operator. The following
commands are available to modify a highlighted clause in the Where list and are found both as
buttons on the right side of the dialog box and as commands from the shortcut menu for the chosen
clause.
The Edit button enables you to re-open a Select Condition dialog box for any conditional clause and
make appropriate changes.
The Insert button enables you to open the Select Condition dialog box and to insert a new clause
before the selected one.
The Remove button enables you to delete the selected clause.
The Clear button enables you to delete all clauses in the Where list.
The ( ) button enables you to join and place brackets around two or more clauses and converts
them into a single line. This most commonly applies to an expression containing clauses that are
joined by both “AND” and “OR” operators where the conditional logic may be unclear. For example,
without brackets, the process order is unclear in the expression “GridA = x AND GridY = y OR GridY
= z”. The command is only available if two or more clauses are selected in the Where list.
The And/Or button enables you to toggle between the AND and OR operators, either of which can
join clauses.
The Extents button enables you to access the Extents dialog box. This dialog box controls the
specifications of the output grid file generated from the Grid Query command.