Name

intersection — Return the set of features from the polygon table that are intersected by selected features in the network table.

Syntax

intersection(query)
              

The INTERSECTION function has the following argument.

query

A string variable containing the query that should be applied to the network table.

Description

This command will return a selection set of the polygons in the Block Attribute table that have been intersected with the lines in the network table that match with the query.

First the command will select records in the Network table that match with the query. The selected lines are then tested for intersection with the blocks in the Block Attribute table. A selection bitset is prepared that describes the resulting selected block polygons.

The entire query is quoted and passed as a string so that it may be evaluated in the context of the Network table. For example, if selecting for values of the RDTYPE column equal to 'N', the encoded query would be

'RDTYPE = \'N\''
                  

Note that the quote characters within the quoted query must be escaped.

The current data table must be the Block Attribute table and the road model must have been loaded with and intersection table, otherwise an error will occur.

Examples

Formula

Description

Result

intersection('RDTYPE = \'N\' and VOLUME gt 0')Returns a selection set of block polygons that are intersected by active new roads.selection set