Working with Shapefiles Containing M and Z Values - MapInfo_Pro - 2023

MapInfo Pro Help

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2023
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MapInfo Pro Help
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1985
Last updated
2023-09-12
Published on
2023-09-12T16:39:16.995549

You can open ESRI shapefiles containing M and Z values as read-only files. MapInfo Pro discards M and Z values when you save these files as MapInfo .TAB files or if you copy them to a new Map window. If you attempt to save a file with M and/or Z values in them, the following message displays.

The new table created will not contain M/Z data from the original table.

Click Continue to create the table without the M and Z values in it or click Cancel to abandon the save process.

Note: The Universal Translator discards the M and Z values when translating from shapefiles to .TAB files, MIF files and MID files to MapInfo .TAB and MIF\MID files.

You can label the PointZ or PointM layers only using these custom label expressions to show Z or M values at each point. However, you cannot save these values to a .TAB file.

To label M and Z values of a shapefile:

  1. Open a shapefile containing M and Z values.
  2. On the HOME tab, in the Windows group, click Tool Windows, and click Layers from the list, to open the Layers window.
  3. Click the Automatic Labels icon for the M or Z layer.
  4. Click the Layer Properties button to display the Layer Properties dialog box.
  5. Select the Label Display tab.
  6. From the Label with list, select Expression to open the Expression dialog box.

    You can only set a Label with expression on a single layer. After selecting multiple layers in the Layer list, the Label with list disables and shows a message that says Mixed.

  7. Type the following:
    • for PointM layers: ObjectGeography(obj, 9)
    • for PointZ layers: ObjectGeography(obj, 8)
  8. Click OK to complete the expression.
  9. Click OK to return to the Layers window.

Currently we do not support native map files with Z and M values in them so you cannot save shapefiles with these values in them to native MapInfo tables.

Note: If you use ExtractNodes( ) function on a shapefile that contains Z or M values, the resulting object returned from the function will not have any Z or M values associated with it. No prompt displays to warn you of the loss of Z or M values.

You can use M and Z values to create a thematic map using a layer expression. In the next example, a PointZ-based shapefile can be used to creating a Grid thematic map using the layer expression ObjectGeography(obj, 8) instead of a field in the table in Step 2 of 3. This interpolates the grid based on the Z value contained for each point in the layer. If the Point objects contain M values, use the expression ObjectGeography(obj, 9).