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seenare(file, dbec, dboc, demvpt, radius)
| Name | Type | Caption | Length | Value range |
|---|---|---|---|---|
| FILE* | str | Input file name | 1 - | |
| DBEC* | List[int] | Input elevation channel | 1 - 1 | |
| DBOC* | List[int] | Output raster channel | 1 - 1 | |
| DEMVPT* | List[float] | DEM View Point (X,Y,Z) | 3 - 3 | |
| RADIUS | List[float] | Radius from DEM view point | 0 - 1 | 0.0 - |
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FILE
Specifies the name of the PCIDSK file that contains the DEM channel and output channel.
DBEC
Specifies the input channel that contains the elevation data (DEM).
DBOC
Specifies the channel to receive the visibile pixels.
DEMVPT
Specifies the view point (x,y) in geocoded coordinates and the elevation (z) above the surface at the geocoded coordinate.
If the view point is off the image, the elevation will be taken as absolute, rather than relative to the surface, because the surface cannot be sampled.
RADIUS
Specifies the radius of the seen area search, in image georeferenced units (usually meters).
If this parameter is not specified, the entire image is searched by default.
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SEENARE determines which pixels in an elevation channel of an input image can be seen from a user-defined view point. The results are saved to the specified output channel. Pixels that can be seen from the given view point are represented by 1; pixels that cannot be seen are represented by 0.
The following parameters are required in SEENARE.
The input file (FILE) contains the input DEM channel (DBEC) and the output channel (DBOC). The input file must be a geocoded image.
The input DEM view point geocoded coordinates and elevation are specified using the DEMVPT parameter.
The RADIUS (Radius from View Point) parameter allows you to set the radius of the seen area search. If this parameter is not specified, the entire image is analyzed.
SEENARE stores the entire DEM in memory. For example:
a 1000x1000 16-bit signed DEM requires 1000x1000x2 = 2000000 Bytes. a 1000x1000 32-bit real DEM requires 1000x1000x4 = 4000000 Bytes. a 6000x6000 16-bit signed DEM requires 6000x6000x2 = 72000000 Bytes a 6000x6000 32-bit real DEM requires 6000x6000x4 =144000000 Bytes.
Ensure that your system has sufficient available memory before running SEENARE.
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Determine the seen area using the demo file irvine.pix, which contains the DEM data in channel 10.
from pci.seenare import * file = 'irvine.pix' # input file dbec = [10] # input elevation channel dboc = [8] # output channel demvpt = [436506,3727485,211] # DEM view point (X,Y,Z) radius = [] # search entire image seenare ( file, dbec, dboc, demvpt, radius )
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