Plot locations around a target or central location
The extension also allows users to plot locations that lie within a certain radius from a central location. This can be done by adding parameters to the formula that enable the extension to find the central location and set the radius:
- QB_DBIDR—The DBID of the table from which the extension queries the central location.
- clistR—Ordered list of field IDs required to plot the central location on the map.
- queryR—Filter condition used by the extension to get the central location.
- rad—Radius (in miles) around the central location within which the markers should lie.
- dist—Users can set the value of this parameter to either Y or N. This parameter is used along with the rad parameter (see above) and toggles the radius feature on or off.
Note
This table should return only 1 location, since it is the central location. Make sure to pass an appropriate filter condition in the queryR parameter.
For QB Maps version 6.0 or lower, only 2 tables can be queried. If the user wishes to set a central location, the second table is used to get the central location. However, for version 6.1 or higher, users can query data from multiple tables (with database IDs passed in as QB_DBID1, QB_DBID2, and so on) and plot only those locations that lie within a certain distance from a location retrieved from the QB_DBIDR table.