Creating Time or Distance Buffers for Objects - MapInfo_Pro - 2023

You can use a routing server's driving regions network to create time or distance buffers around map objects to see your data in a new way. Keep in mind that these buffers are not like standard straight line circle buffers, but are rather based on the speed that a driver can travel on a particular road network.

Before you begin this process, we recommend that you set up your own default routing server using the instructions in Setting the Routing Server Preferences.

To create time or distance buffers for an object or objects:

1. Open a table that you want to add the time or distance buffer to and make sure the layer is editable.
2. Select the point object or objects you want to create the buffer or buffers for in the Map window.
3. On the SPATIAL tab, in the Create group, on the Regions list, click Convert to Regions, and Drive Regions (Objects).

   If a user name and password is required, the Server Password dialog box displays. Enter the user ID and the password for the routing server. Click OK. One of these things occurs:

   • If you have a default routing server, the Create Driving Regions dialog box displays.
     Note: You may notice that the Add button in the Create Driving Regions dialog box or the Geocode using Server dialog box is disabled if you have reached the limit on the number of request values (number of address batches, times, or distances) you have sent to the server. Newer versions of Envinsa allow the server to set limits on the server side, and MapInfo Pro uses these limits. You may see some changes in behavior when you switch servers and the new server has different limits.

     Another difference you may see is that a particular quantity of address batches, times or distances may work for one server but not for another.

4. Select the server, request type and request value options for this request.

   Routing Server

   Select the server for the request from the drop-down list.

5. Select the type of buffer request you want to create from this box. Do one of the following:
   • Click Time and select the time units to create a time buffer
   • Click Distance and select the distance units to create a distance buffer

     Request Values lets you select the buffer values for the driving region request. For example, to create time buffers for 5, 10, and 15 minutes, you can add or edit the existing request values to read 5, 10, and 15.

     Note: The items in the list are always sorted in ascending order of the value.

     You can add or remove values using the Add and Remove buttons. See the Rules when Adding a Driving Value for more information.

     To edit a request value in this box, double-click it and type over the entry or press F2.

     To change a region style, double-click the image to display the Region Style dialog box and make your changes or press <Ctrl+F2>.

6. Select the road network details you want the server to use to calculate the buffers you specified.
   • Use major roads only in calculation – Select this check box to use only the server network's major roads in the buffer calculation. The network can include major roads only or all roads. A major road is a main road or highway.
     Note: When you select this option you may get the results faster, but they may be less precise.
   • When multiple drive values are defined – Use this option only if you are requesting more than one buffer value in this calculation.
   • Create non-overlapping objects – Select this option to create buffers that do not overlap.
   • Create overlapping objects – Select this option to create drive value buffers that overlap.
7. Select the advanced options for this request to specify the result types for this request.
   • Exclude holes from results – Select this button to indicate whether the resulting geometries can contain holes. These pockets of territory are often neighborhoods of local roads that are hard to cross.
   • Exclude islands from results – Select this button to indicate whether the resulting geometries can include islands outside of the main boundary. These areas are frequently located off exit ramps of major highways. The results can include the islands or ignore them entirely.
   • Speed used for off-road travel/Propagation factor – The label for this field changes depending upon the driving region request you selected (time or distance). For a time calculation, the Speed used for off-road travel label displays. For a distance calculation requests, the Propagation Factor label displays.

     Use the Speed field to indicate the speed you want the server to use for roads that are not part of the server's network. The default value for this field is 15, but you can add any whole or decimal number. The Unit drop-down list only displays when you choose an off-road network speed.

     Use the Propagation Factor field to enter a default percentage that MapInfo Pro will use to calculate the off-road distance for each buffer boundary. Off-road distance or off network distances might include driveways or access roads. The propagation factor is expressed as a percentage of the distance calculation between the starting point and the buffer boundary. The default value for this property is .16 and the range is between .01 and 1.

   • Limit off-road travel – Use this check box to limit the off-road distance used in the calculation. This option can be useful in preventing buffers that extend into areas that you cannot travel in (such as a swamp or body of water). When you select this option, the you can enter a distance value and its units. The default value for this field is 15, but you can enter any integer. The corresponding field and drop-down list are enabled when you select the check box.
   • Include only point objects as input – Use this option to skip any table objects that are not points. No errors result. This option is selected by default.
   • Reset options from connection – Use this option to return to the previous options from the current connection.
   • Smoothing factor – Use this slider control to indicate the smoothness of the polygon you have requested. MapInfo Pro uses this entry to calculate the number of nodes used to create and display in the resulting buffer. When this number is low, there are fewer points and the transmission time is less. You can specify a value between 1% and 100%. The corresponding static text control displays the current value. This bar is always enabled.
8. When you have completed these selections, click Next to display the Data Aggregation dialog box.
   Note: When you are creating driving regions in the Cosmetic layer, click OK to begin the process, since no data aggregation occurs.
9. Do one of the following:
   • Highlight the field you want to place the new data into and select the Drive Value option to put the drive value associated with the resulting geometry into the selected (numeric) column.
   • Highlight the field you want to place the new data into and select the Drive Unit option to put the drive unit for the resulting geometry into the selected (character) field.
10. Click OK to begin the driving region processing. A status bar displays. Then the driving regions you specified display.

    

    These driving regions were created with non-overlapping objects.