Pitney Bowes MapInfo Professional - Manual (Page 297)

Many customers use the contouring process to create signal coverage maps, which requires large object
sizes to create highly detailed coverage areas. To accommodate this need, we have increased the limit
on number of nodes and the number of polygons or polylines that can be stored in objects.
Theoretically, the size of an object is only limited by the amount of memory in the system, but for practical
reasons, a limit is imposed to work within limits of file size and most system memory limits. Currently,
the object size limit is 1,073,741,823 bytes in memory. This limit is imposed so that an object of this size
can be saved into a MAP file. All MapInfo Professional files have a theoretical limit of 2GB, but due to
header size and other required Map file contents, the actual size limit has to be somewhat less.
The node limit is 134,217,724 nodes in any object. This is the actual number of nodes that can fit into
this 2GB memory size limit. It will be difficult to reach this node limit because memory allocation may
prohibit it. It may not be possible to create a Map this size on a computer being used to accommodate
an object this size; the program may throw an error when you try it.
Keep these notes in mind:
• For regions, the theoretical maximum number of polygons in a multi-polygon region or collection is
20,648,881 polygons that can fit into the size limit for all objects given above.
• For polyline objects, the theoretical maximum number of segments in a multi-segment polyline is
24,403,223 that can fit into the size limit for all objects given above.
• For multipoint objects, the theoretical maximum number of nodes is 134,217,724 that can fit into the
size limit for all objects given above.
Aggregating and Disaggregating Data
If you have data attached to map objects that will be edited, you can proportion the data for each field
to match the new object(s). This is called data aggregation or disaggregation, depending on whether
you are combining or splitting objects. MapInfo Professional calculates new data values for the object
depending on how you specify the aggregation or disaggregation.
When combining objects, you can choose from several methods of data aggregation, including:
• Sum - adds the field values from the original objects to create a total for the field in the new object.
• Average - averages the field values from the original objects.
• Weighted average - gives more weight to one value over another when averaging. You can choose
a numeric field in your table as the weighting factor or choose area (where the weighted average is
based on the relative geographic area of the regions to be combined).
• Value - stores a specific value in the field of the new object.
• No Change - maintains the value of the target object in the new object.
When splitting or erasing portions of a map object, you can choose from:
• Blank - removes the original value of the target object.
• Value - maintains the original value of the target object.
• Area proportion - removes a portion of the original value based on the size of the new object.
With any of the editing operations under Set Target, you can elect not to bring over any data at all by
choosing the No Data check box. You might do this, for instance, if you are only editing map objects for
presentation purposes and do not need any data associated with the objects.
The Data Aggregation (or Disaggregation) dialog box displays after you have set the target, chosen
the modifying object, and chosen an editing operation. In these dialog boxes, you must specify how you
want the data calculated for each field. Once you are satisfied with the aggregation method, you can
carry out the editing operation.
297 MapInfo Professional User Guide
Chapter 11: Buffering and Working with Objects