CreateViewshedOnRoute

Creates a graphical representation of all the visible areas of the terrain, within a field of view, from a given viewing point. The user can define viewer height and radius of viewshed analysis. The calculated route viewshed can be displayed as: 

§   Individual viewshed results for each selected point along the route

§   A single composite viewshed showing visible area from any of the route’s waypoints

§   A series of individual viewshed results that display according to a set timespan

 

JavaScript
CreateViewshedOnRoute(        Route,        AnalysisType,        ViewerHeight,        Distance,        SampleInterval,        RaySpacing,        DistanceBetweenWaypoints,        TimeStart,        TimeEnd,        ParentGroupID,        Description)

 

C#
string CreateViewshedOnRoute(        ILineString Route,        MultipleViewshedAnalysisType AnalysisType,        double ViewerHeight,        double Distance,        double SampleInterval,        double RaySpacing,        double DistanceBetweenWaypoints,        object TimeStart,        object TimeEnd,        string ParentGroupID = "",        string Description = "")

 

C++
HRESULT CreateViewshedOnRoute(        ILineString* Route,        MultipleViewshedAnalysisType AnalysisType,        double ViewerHeight,        double Distance,        double SampleInterval,        double RaySpacing,        double DistanceBetweenWaypoints,        VARIANT TimeStart,        VARIANT TimeEnd,        BSTR ParentGroupID,        BSTR Description,        BSTR *ViewshedGroupID)

Parameters

Route

An ILineString object representing the geometry that defines the route.

AnalysisType

An enum that determines the Viewshed analysis type. The following are the possible values:

·          MVT_NOT_VALID = -1
Viewshed is invalid.

·          MVT_VIEWSHED_ON_ROUTE = 0
Displays the viewshed as individual viewshed results for each waypoint along the route.

·          MVT_TIMESPAN_VIEWSHED_ON_ROUTE = 1
Displays the viewshed as a series of individual viewshed results that display according to a set timespan.

·          MVT_CUMULATIVE_VIEWSHED_ON_ROUTE = 2
Displays the viewshed as a single composite viewshed showing visible area from any of the route’s waypoints.

ViewerHeight

The height of the viewer waypoints on the route.

Distance

The radius of the viewshed analysis from each of the route’s waypoints.

SampleInterval

The distance between terrain samples for the measurement along each ray. A smaller sample size is more accurate but slower to calculate.

RaySpacing

The space in degrees between each ray that TerraExplorer samples. TerraExplorer samples several rays (lines of sight) in the area sector. The smaller the ray spacing, the more accurate the measurement, but the longer it takes to calculate.

DistanceBetweenWaypoints

The distance between viewsheds along the route.

TimeStart

The start time assigned to the Viewshed on Route results. See “Time” for information on valid formats for this parameter.

TimeEnd

The end time assigned to the Viewshed on Route results. See “Time” for information on valid formats for this parameter.

ParentGroupID

The Project Tree group in which the model is created. If it is set to an empty string, the object is created under the root. You can obtain the GroupID by one of the following methods:

·          Create the group using IProjectTree80.CreateGroup.

·          Find the group, if you know the name, using IProjectTree80.FindItem.

·          Traverse the Tree using IProjectTree80 methods such as GetNextItem, until you come to the desired GroupID.

Description

The name of the viewshed object as it appears in the Project Tree. If an empty string is passed into this parameter, TerraExplorer assigns it a unique name.

Return Value

ViewshedGroupID

The ID of the viewshed object.

Exceptions

See: HRESULT Return Values for a list of possible values returned by the HRESULT.