Cadcorp SIS API Methods

CreateIsoRoute Method

Description

Create a MultiLineString Item (or a LineString Item) covering all connected places which can be reached from a position, within a given cost. When the cost is related to time, this query is often called an Isochrone.

Syntax

Visual Basic
Public Function CreateIsoRoute( _ ByVal x As Double, _ ByVal y As Double, _ ByVal z As Double, _ ByVal r As Double, _ ByVal isoVal As Double, _ ByVal formula As String, _ ByVal filter As String, _ ByVal locusNoGo As String _ ) As Integer

Visual Basic

Public Function CreateIsoRoute( _
   ByVal x As Double, _
   ByVal y As Double, _
   ByVal z As Double, _
   ByVal r As Double, _
   ByVal isoVal As Double, _
   ByVal formula As String, _
   ByVal filter As String, _
   ByVal locusNoGo As String _
) As Integer

Parameters

x

The x position to start from.

y

The y position to start from.

z

The z position to start from.

r

The maximum distance from the start point to linear geometry. The topological algorithm will spread out from the closest Item found. The distance from the point to the closest Item is not included in the cost calculation. Ideally, the start point should be on an item.

isoVal

The maximum cost to incur during route finding.

formula

The expression, or simple property, to use in the route finding calculation as the "cost" of a Link item. For example, using the simple property Length will find the shortest route, and using the expression "_length#/Speed#", provided each Link has a user-defined Speed# property, will find the quickest route. Any expression may be used, although if a string expression is used it must be a string representation of a numeric value. See Property Expression Syntax for details.

filter

Optionally specifies a named Filter which all Items must pass to be considered as part of a route.

locusNoGo

Optionally specifies a named Spatial Filter through which no route may pass.

The named Spatial Filter used ("NoGo" in the following examples) will normally have its testing mode set to exclude any Items which cross it, using a call similar to the following:

CreateLocusFromItem("NoGo",SIS_GT_INTERSECT,SIS_GM_GEOMETRY)

Remarks

This method can find a route over any geometry, not just Link/Node topology, by specifying an empty string for this argument. In this case, length is used as the cost.

Available: GEO MM ME MD OM OD OV SISpy

Group:

Topology Methods

Example

This example converts length travelled at 30 mph to minutes, i.e. '5280' feet in a mile, '3.2808' feet in a metre.

sis.CreateIsoRoute (2000, 1500, 10, 30, 15, "_length#/((30*5280/3.2808)/60)", "links", "NoGo" )

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