First_node
network-functions first node
syntax
- first_node(arc_polygon_dataitem)
definition
first_node(arc_polygon_dataitem) results in a point data-item with the coordinates of the first point of an arc or polygon of argument arc_polygon_dataitem.
description
Use the arc2segm function to split an arc in segments.
applies to
data item arc_polygon_dataitem with fpoint or dpoint value-type and composition type type arc or polygon.
example
attribute<fpoint> first_node (Road) := first_node(road/geometry);
| road/geometry | first_node |
|---|---|
| {2 {399246, 112631}{398599, 111866}} | {399246, 112631} |
| {3 {398599, 111866}{399495, 111924} {401801,111524}} | {398599, 111866} |
| {2 {401529, 114921}{398584, 114823}} | {401529, 114921} |
domain Road, nr of rows = 3