MapInfo Products KnowledgeBase

Product: MapInfo
Version: 7.0
Platform: Not Platform Related
Category: Object Manipulation

Summary:
Creating buffers based on an existing table structure.

Question:
This document describes an alternative way to create buffers around points or other object types and still retain the data behind the original objects. Another Knowledgebase document describes a method using the MapBasic window on a copy of a table-->.

While that method works well, version 7.0 has new functionality to create a table based on an existing table’s structure and allows for more flexibility when creating the new buffer table.

Answer:
A common customer relationship management task is locating customers that are within a particular distance from a company’s store, warehouse, or distribution center and joining that store data with the customer data.

When two tables are represented graphically as symbols, it is a simple matter within MapInfo Professional to create buffers around the company stores and find all the customers that fall within the buffers. However, linking all the data can be a little tricky.

Assume there is a map, for example, with “Store” locations in a table represented as red stars and a “Customer” location table represented as blue diamonds.










Using functionality new to MapInfo Professional 7.0 in the File>New Table dialog, follow these steps to create the buffer table:

1. Choose File>New Table. Check “Add to Current Mapper” and uncheck all other boxes.
2. Select the radio button labeled: “Using Table” and select the Stores table from the dropdown.
3. Click Create.



4. Notice that the columns listed in the New Table Structure dialog are the same as those in the original Stores table. This dialog used the existing Stores table structure as a template. Columns can be added or removed if desired or simply click create to copy the exact structure of the Stores table.



5. Once the Create button is clicked, the new table can be named and saved to any desired folder location. In this example, the table will be named StoreBuffers.



6. Going to Map>Layer shows the new table listed. The new StoreBuffers table has been made mappable and it is editable and ready to be populated with buffers. If viewed in its own map window, it would appear as a blank, white map.



7. Now, choose Query>SQL Select.
8. Choose the Stores table from the Table dropdown in the upper right corner.
9. Uncheck the “Browse Results” box so that everything gets selected from the map window. Click OK.



10. The stores are now selected.



11. Choose Objects>Buffer.
12. Fill in the radius of the buffers in the “value” field. In this example, the radius will be 20 miles.
13. Increase the smoothness if desired. This will make the buffer appear less jagged.
14. In this example, choose “One buffer for each object”. Click Next.



15. The data aggregation dialog will appear. In this case, even though there is a numeric field, the data cannot be added or “summed”. If “one buffer of all objects” were chosen in the previous dialog, the numeric values could be summed or averaged because only one buffer and one row would be created instead of four buffers with four rows as in this example.



16. After clicking OK, the buffers are created and selected. At this point, since the table is still editable and the objects are selected, the style of the buffer objects can be modified by going to Options>Region Style. In this example, the border has been made thicker.



17. Choose Map>Layer Control and reorder the layers if desired, and uncheck the box under the pencil next to the StoreBuffers so the table will no longer be editable. Then, choose File>Save Table to commit and save the StoreBuffers table.



Here is the final map and a view of the browser from the StoreBuffers table.





Now, when performing a query through SQL Select and joining the Customer table to the StoreBuffers table where Customer.obj is within StoreBuffers.obj, the resulting query will have all the columns and data from both base tables. Now, it is easy to see what customer is related to which store location.

Last Modified:
Document URL: http://testdrive.mapinfo.com/techsupp/miprod.nsf/kbase_by_product/173A1F884DA4A36785256C54004D5A3E

Creating buffers based on an existing table structure.^173A1F884DA4A36785256C54004D5A3E^Y