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Calculates several characteristics for each triangle of a
PolygonZ TIN
- Minimum elevation
- Maximum elevation
- Mean elevation
- Slope - identifies the slope, or maximum rate of elevation change for each triangle
- Aspect - the values of the output field represent the compass direction of the
slope (horizontal direction in which a slope faces); 0
is true north, a 90 degree aspect is to the east etc. For flat triangles (slope = 0)
the value of -1 is assigned for the aspect
- Hill Shade- computes the brightness of each triangle based on a light source location.
- 3D Area
Inputs:
- A PolygonZ TIN feature layer
- Characteristics to be calculated
- Parameters for Hill Shade ( if Hill Shade option is selected )
- azimuth - the azimuth angle of the light source. The azimuth is expressed in positive
degrees from 0 to 360, measured clockwise from the north. The default is 315 degrees.
- altitude - the altitude angle of the light source above the horizon. The altitude is
expressed in positive degrees, with 0 degrees at the horizon and 90 degrees directly
overhead. The default is 45 degrees.
Outputs:
- New polygon Z feature class. Several fields are added to the attribute table, depending on
the options selected
- ET_ElMin - minimum elevation values for
each triangle
- ET_ElMax - maximum elevation values for
each triangle
- ET_ElMean - mean elevation values for each
triangle
- ET_Slope_D - the slope (maximum rate of
elevation change) of each triangle in Degrees (from 0 to 90)
- ET_Sope_P - the slope (maximum rate of
elevation change) of each triangle in percents
- ET_Aspect - the aspect (compass direction
of the slope - 0 is North, 90 degrees - East, 180 degrees - South, 270 -
West) of each triangle
- ET_ACode - aspect categories
- N - North ( 0 to 22.5 and 337.5 to
360)
- NE - North East (22,5 to 67.5)
- E - East (67.5 to 112.5)
- SE - South East (112.5 to 157.5)
- S - South (67.5 to 112.5)
- SW - South West (202.5 to 247.5)
- W - West (247.5 to 292.5)
- NW - North West (292.5 to 337.5)
- U - Undefined - Slope = 0
- ET_AreaZ - the 3D area of each triangle
Notes:
- If the PolygonZ TIN is created using ET
Surface, you need to analyze the tin only if you need to obtain the values
for Hill Shade or calculate them for different Azimuth and/or Altitude
of the light source
- If you have PolygonZ TIN created with ET
GeoWizards (or some other application), you will need to use the Analyze TIN
function in order to get correct parameters for use with the ET Surface
functions.
ToolBox
implementation
Command line syntax
ETS_GPAnalyzeTIN <Input
TIN> <Out Feature Class> {Light Azimuth} {Light
Altitude}
Parameters
| Expression |
Explanation |
|
<Input TIN> |
A PolygonZ
TIN (feature layer or feature class) |
| <Out Feature Class> |
A String
- the full name of the output feature class. |
| {Light
Azimuth} |
A Double representing azimuth
of the light source (0 to 360). 0 indicates North, 90 - East, 180 - South,
270 - West |
| {Light
Altitude} |
A Double representing the
altitude of the light source in degrees (0 to 90) |
Scripting syntax
ETS_GPAnalyzeTIN (Input
TIN, Out Feature Class, Light Azimuth,
Light Altitude)
See the explanations above:
<> - required parameter
{} - optional parameter
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products mentioned are trademarks of Environmental Systems Research
Institute, Inc.
Copyright: Ianko Tchoukanski |