Creating a Legend with Joined Information - MapInfo_Pro - 2023

MapInfo Pro Help

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MapInfo Pro Help
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2023-09-12
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2023-09-12T16:39:16.995549

When creating a legend, you can select to perform a join to add a temporary column from another table that you can use for your feature descriptions in a legend frame. You can use this column for your feature descriptions. Again, this column can be any column value, or one that you create. This column is saved automatically in the workspace.

Creating a legend using joined information is useful if you have a large table of many records that fall into a small number of categories. Instead of repeating the category descriptions over all the records, a code is assigned to each category and stored for each record instead of a description. A different table stores the code and its description. You can use the category description in the legend, not the code, once a join between two tables exists. You can do this by using the description column for legend labels. (It is also possible to create this kind of look-up table in a table's metadata.)

Join option is only available when there are at least two tables open in MapInfo Pro.

To create the legend using joined information:

  1. Make the Map window active.
  2. From the MAP tab, select Add Legend and make your selections in Step 1 and Step 2 screens. For details, refer to Creating a Legend for your Map.
  3. In the Create Legend ­ Frame Properties screen, from the Label styles with drop-down list, choose Join.
  4. In the Update Column dialog box, from the Get Value From Table drop-down list, choose the table you want to join to and then click Join.
  5. In the Specify Join dialog box, specify the matching columns in the tables to join and then click OK.
  6. In the Update Column dialog box, select one of the following from the Calculate drop-down list:
    • Count to display a count for legend labels.
    • Value and then select the column name or expression to use for legend labels from the next drop-down list. If you select expression, then in the Expression dialog box type the expression you want to create or use the drop-down lists.
  7. Click OK in the dialogs to return to the Frame Properties screen.
  8. Click Finish to display the legend.
Note: If the temporary column name is saved to legend metadata, but the temporary column is not saved in the workspace (for example you close tables and the join), you'll get an error when you re-create the legend from metadata. You must either redo the join to get the temporary column, or choose a different label expression for the legend text.

For an example of creating a theme using a join, see Updating Columns using Thematic Mapping.

See Also:

Geographic and Descriptive Joins