Connect

network-functions connect

syntax

1. connect(point_dataitem_dest, point_dataitem_org)
2. connect(arc_polygon_dataitem, point_dataitem, [optional]maxSqrDist)

definition

The connect function connects nearby geometries. It has two variants:

1. Both arguments are single point data items (syntax 1). This variant is used to find the nearest point_dataitem_dest for each point_dataitem_org. The function results in a relation for the domain-unit of point_dataitem_org towards the domain unit of point_geom_dest.
2. The first argument is an arc or polygon, the second argument is a point data item (syntax 2). The points of point_dataitem are connected to the nearest arc/polygon outline of the arc_polygon_dataitem. Cut points are added as (intermediate) points to the arc_polygon_dataitem The functions results in a new domain unit with:
   • a geometry subitem (previously named UnionData) containing a new geometry, combining the original geometry of the arc_polygon_dataitem and the new connections to the point_dataitem.
   • an arc_rel subitem (previously named Nr_OrgEntity) with a relation to the domain of the arc_polygon_dataitem (null for the new connections).

Additionally, an optional maxSqrDist can be specified, with the squares of the maximum distance that each point of the 2nd argument is allowed to look around.

The figure illustrates this second variant. The dark green houses represent the point_dataitem, the light green lines the arc_polygon_dataitem. The resulting UnionData subitem of the connect function is presented with the blue lines.

description

The second variant is often used to build a network typology. In this variant, typically an arc connection is made with the point_dataitem as first point and the cut point on the arc_polygon_dataitem as last point.

If the distance in the precision of the value-type to the nearest point/arc/polygon is similar for multiple features, points are connected to the point/arc/polygon with the lowest index number.

In both variants, the first argument should contain unique geometries. Use the unique function to make a domain unit with unique geometries.

The connect_info function is used in the second variant to present information on the extra connections, e.g. the distance of each connection and the coordinates of the CutPoint on the connected arc/polygon.

applies to

• data items point_dataitem_org, point_dataitem_dest, arc_polygon_dataitem and point_dataitem with fpoint or dpoint value type
• data item arc_polygon_dataitem with composition type type arc or polygon. Be aware, if you connect points to polygons, always use a split_polygon first of the polygon geometry to get rid of the connection lines in polygons between islands and lakes.

conditions

The value type of all arguments must match.

example

variant 1:

attribute<destination> destination_rel  (origin) := connect(destination/geometry, origin/geometry);

domain origin, nr of rows = 5

domain destination, nr of rows = 4

variant 2:

unit<uint32> location2road := connect(road/geometry, location/geometry);

domain road, nr of rows = 3

domain location, nr of rows = 8

domain location2road, nr of rows = 19

see also

• connect_eq
• connect_ne
• connect_neighbour
• connect_info
• capacitated_connect