ArcObjects Library Reference (GeoAnalyst)  

ISurfaceOp2.Visibility Method

Performs visibility analysis on a surface based on a set of input observation points.

[Visual Basic .NET]
Public Function Visibility ( _
    ByVal GeoDataset As IGeoDataset, _
    ByVal observers As IGeoDataset, _
    ByVal visType As esriGeoAnalysisVisibilityEnum, _
    [ByRef pZFactor As Object], _
    [ByRef pRefractivityCoefficient As Object] _
) As IGeoDataset
[C#]
public IGeoDataset Visibility (
    IGeoDataset GeoDataset,
    IGeoDataset observers,
    esriGeoAnalysisVisibilityEnum visType,
    ref object pZFactor,
    ref object pRefractivityCoefficient
);
[C#]

Optional Values

pZFactor   To indicate that this parameter is undefined, first define a variable object Missing = Type.Missing; then pass this in as ref Missing.
pRefractivityCoefficient   To indicate that this parameter is undefined, first define a variable object Missing = Type.Missing; then pass this in as ref Missing.
[C++]
HRESULT Visibility(
  IGeoDataset* GeoDataset,
  IGeoDataset* observers,
  esriGeoAnalysisVisibilityEnum visType,
  VARIANT* pZFactor,
  VARIANT* pRefractivityCoefficient,
  IGeoDataset** outGeoDataset
);
[C++]

Parameters

GeoDataset [in]

  GeoDataset is a parameter of type IGeoDataset

observers [in]

  observers is a parameter of type IGeoDataset

visType [in]

  visType is a parameter of type esriGeoAnalysisVisibilityEnum

pZFactor [optional]
  pZFactor is a parameter of type VARIANT

  To indicate this parameter is undefined pass a reference to a VARIANT with type VT_ERROR and scode value of DISP_E_PARAMNOTFOUND.

pRefractivityCoefficient [optional]
  pRefractivityCoefficient is a parameter of type VARIANT

  To indicate this parameter is undefined pass a reference to a VARIANT with type VT_ERROR and scode value of DISP_E_PARAMNOTFOUND.

outGeoDataset [out, retval]

  outGeoDataset is a parameter of type IGeoDataset

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Remarks

geoDataset

an input Raster, RasterDataset, RasterBand, or RasterDescriptor used to define the z values for visibility calculations and analysis

observers

input FeatureClass or FeatureClassDescriptor containing containing point or line features used as observation points

visType

an esriGeoAnalysisVisibilityEnum specifing the type of visibility analysis to be performed

esriGeoAnalysisVisibilityFrequency the output will only record the number of times each raster-cell location can be seen by the observation points

The observation frequency will be recorded in the Value item in the output Raster's value attribute table.

esriGeoAnalysisVisibilityObservers the output for each cell location will contain a binary-encoded value which can be decoded to identify the observation# of each observation point that can see each Raster cell

The encoded value will be recorded in the Value item in the output Raster's value attribute table. In addition to the standard items, Value and Count, in the value attribute table, a new item named OBSn will be created in the value attribute table for each observer n in the input point dataset. The OBSn item will be assigned a value of 1 if the cell can be seen by observer n, or a value of 0 if it cannot be seen.

esriGeoAnalysisVisibilityFrequencyUseCurvature the output will only record the number of times each raster-cell location can be seen by the observation points

The observation frequency will be recorded in the Value item in the output Raster's value attribute table. It also corrects for earth curvature and refraction.

esriGeoAnalysisVisibilityObserversUseCurvature the output for each cell location will contain a binary-encoded value which can be decoded to identify the observation# of each observation point that can see each Raster cell

The encoded value will be recorded in the Value item in the output Raster's value attribute table. In addition to the standard items, Value and Count, in the value attribute table, a new item named OBSn will be created in the value attribute table for each observer n in the input point dataset. The OBSn item will be assigned a value of 1 if the cell can be seen by observer n, or a value of 0 if it cannot be seen. It also corrects for earth curvature and refraction.

[pZFactor]

The number of ground x, y units in one surface Zunit.

The geoDataset ZUnits are multiplied by the specified zFactor to adjust the output Raster ZUnits to another unit of measure. If no zFactor is specified the value of the zFactor is 1. Higher z values will result in a more exaggerated relief (surface) and thus in a more extreme shading.

[pRefractivityCoefficient]

Coefficient of the refraction of visible light in air. The default value is 0.13

 

See Also

ISurfaceOp2 Interface