ISIS 3 Application Documentation
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Create a digital elevation model from one or more control network files.
The cnet2dem applicaton produces an interpolated digital elevation model (DEM) from one or more control networks. There are fourteen different algorithms that may be selected that provide either absolute radius values or other information, such as radius and point distance statistics, computed at each output DEM pixel value. The range and type of the DEM generated from cnet2dem is a standard ISIS map definition or a projected ISIS cube file containing a map definition. You can select any number of algorithms in the ALGORITHM parameter. The output cube will contain the same number of bands in the same order algorithms are specified in the parameter. The BandBin group Name parameter will also contain the name of the algorithm that cooresponds to the data contained in each band.
Note that the control network is expected to be the output results of the bundle adjustment computed by jigsaw. Additionally, jigsaw must have been used to solve for radius. Otherwise, you will be using the apriori radius which is typically the PCK defininition (will will result in the ellipsoid).
The adjusted latitude/longitude coordinate is used to compute the location of all the control points. The adjusted coordinates are compute by jigsaw. If it doesn't exist, the apriori coordinate will be used but know that this coordinate is typically computed from each reference image in each control point (so it may not be consistent).
Also, in some cases, one or more of the algorithm radius bands in the output of cnet2dem may be sufficient for direct use as an ISIS shape model (after demprep is run!). However, this is generally not the case and some of the radius bands may require a series of filters to smooth out the results.
|CNET||Master control network file to match.|
|CNETLIST||List of merger control network files.|
|MAP||Specifies a file containing the output map specfications.|
|TO||Output DEM ISIS cube|
|TRIM||Null all pixels outside lat/lon boundaries.|
|SEARCH||Optional tolerance for radial search range (meters).|
|DISTANCE||Specifies the radial search distance to search.|
|KDNODES||Specify the leaf size of the kd-tree.|
|NEIGHBORS||Specify the number of nearest NEIGHBOR points|
|MINPOINTS||Specify the minimum number of search points per pixel.|
|SIGMARADIUS||Specifies noise tolerance in radius.|
|ALGORITHM||Type of data to provide a each output pixel location.|
A single control network file used to create the point cloud to produce the interpolated output DEM radius at each output pixel.
A list of control network files that are combined into the point cloud to produce the interpolated output DEM radius at each output pixel.
A standard ISIS map definition file or a map projected ISIS cube file containing a mapping group. This file will be used to create the output DEM ISIS cube.
Specifies the name of an output ISIS cube file that is created to write the DEM. The output DEM may require demprep to be run on it before it can be used as an ISIS DEM shape model.
If this option is selected, pixels outside the latitude/longtiude range will be trimmed (set to null). This is useful for certain projections whose lines of latitude and longitude are not parallel to image lines and sample columns.
This parameter allows the user to specify the size of the radius search at each output map pixel. If not provided, the pixel resolution of the projection is used to specify the search diameter.
Radial distance in meters to search for control points measured from the center of the ouput map pixel.
Number of leafs in the kd-tree structure.
Specify number of control points that will be selected in the nearest NEIGHBOR search query to produce the output DEM pixel values.
Specify number of minimum number of points to accept from the RADIAL search query of the point cloud at each output DEM pixel. If the result set for each pixel does not have at least MINPOINTS, NULL values will be written to the output DEM pixel.
If provided, a noise filter is applied to the radius of the point set at each output pixel. The SIGMARADIUS is the number of standard deviations from the median radius from all control points.
This parameter provides numerous methods to compute the output radius value for a given latitude, longitude and map grid point. Any number of methods can be specified by enetering a comma-delimited lisf of the method names.
|AverageRadius||None||For all control points found in the RADIAL and/or NEARESTNEIGHBOR kd-tree search, computes the average radius value (the average Euclidean distance of all points from the surface to the center of the body).|
|MaximumRadius||None||Computes the maximum radius (in meters) of the control points.|
|MinimumRadius||None||Computes the minimum radius (in meters) of all control points.|
|MedianRadius||None||Computes the median radius (in meters) of all control points.|
|StandardDeviationRadius||None||Computes the standard deviation (in meters) of the radii of the control points.|
|MaximumDistance||None||Computes the maximum surface distance (in meters) of all control points with respect to the latitude, longitude coordinates of the central pixel.|
|MinimumDistance||None||Computes the minimum surface distance (in meters) of all control points with respect to the latitude, longitude coordinates of the central pixel.|
|MedianDistance||None||Computes the median surface distance (in meters) of all control points with respect to the latitude, longitude coordinates of the central pixel.|
|AverageDistance||None||Computes the average surface distance (in meters) of all control points with respect to the latitude, longitude coordinates of the central pixel.|
|StandardDeviationDistance||None||Computes the standard deviation (in meters) of the surface distance of all control points with respect to the latitude, longitude coordinates of the central pixel.|
|FrankeNelsonRadius||None||Computes the radius of the control points (in meters) using the Franke-Nelson method.|
|ShepardsRadius||None||Computes the radius of the control points (in meters) using Shepard's weighted algorithm.|
|NaturalNeighborRadius||None||Computes the radius of the control points (in meters) using the Nearest Neighbor interpolation algorithm.|
|TypeCount||None||Returns the total number of pixels in the point collection. It additionally applies a signed (+/-1) value to indicate if the FLANN (Fast Library for Approximate Nearest Neighbors) search type was nearest neighbor (-1) or radius (+1).|
|Kris Becker||2015-11-13||Original Version|
|Tyler Wilson||2016-03-10||Minor documentation corrections.|