Generate a RPC sensor model¶

Detailed description¶

This application generates a RPC sensor model from a list of Ground Control Points. At least 20 points are required for estimation wihtout elevation support, and 40 points for estimation with elevation support. Elevation support will be automatically deactivated if an insufficient amount of points is provided. The application can optionnaly output a file containing accuracy statistics for each point, and a vector file containing segments represening points residues. The map projection parameter allows defining a map projection in which the accuracy is evaluated.

Parameters¶

This section describes in details the parameters available for this application. Table [1] presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is GenerateRPCSensorModel .

Output geom file Geom file containing the generated RPC sensor model.

Input file containing tie points Input file containing tie points. Points are stored in following format: col row lon lat. Line beginning with # are ignored.

Output file containing output precision statistics Output file containing the following info: ref_lon ref_lat elevation predicted_lon predicted_lat x_error_ref(meters) y_error_ref(meters) global_error_ref(meters) x_error(meters) y_error(meters) overall_error(meters).

Output vector file with residues File containing segments representing residues.

Output Cartographic Map Projection Parameters of the output map projection to be used. Available choices are:

• Universal Trans-Mercator (UTM) : A system of transverse mercator projections dividing the surface of Earth between 80S and 84N latitude.

• Zone number : The zone number ranges from 1 to 60 and allows defining the transverse mercator projection (along with the hemisphere).
• Northern Hemisphere : The transverse mercator projections are defined by their zone number as well as the hemisphere. Activate this parameter if your image is in the northern hemisphere.
• Lambert II Etendu : This is a Lambert Conformal Conic projection mainly used in France.
• Lambert93 : This is a Lambert 93 projection mainly used in France.
• WGS 84 : This is a Geographical projection
• EPSG Code : This code is a generic way of identifying map projections, and allows specifying a large amount of them. See www.spatialreference.org to find which EPSG code is associated to your projection;

• EPSG Code : See www.spatialreference.org to find which EPSG code is associated to your projection.

Elevation management This group of parameters allows managing elevation values. Supported formats are SRTM, DTED or any geotiff. DownloadSRTMTiles application could be a useful tool to list/download tiles related to a product.

• DEM directory: This parameter allows selecting a directory containing Digital Elevation Model files. Note that this directory should contain only DEM files. Unexpected behaviour might occurs if other images are found in this directory.
• Geoid File: Use a geoid grid to get the height above the ellipsoid in case there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles. A version of the geoid can be found on the OTB website (http://hg.orfeo-toolbox.org/OTB-Data/raw-file/404aa6e4b3e0/Input/DEM/egm96.grd).
• Default elevation: This parameter allows setting the default height above ellipsoid when there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles, and no geoid file has been set. This is also used by some application as an average elevation value.

Load otb application from xml file Load otb application from xml file.

Save otb application to xml file Save otb application to xml file.

Example¶

To run this example in command-line, use the following:

otbcli_GenerateRPCSensorModel -outgeom output.geom -inpoints points.txt -map epsg -map.epsg.code 32631

To run this example from Python, use the following code snippet:

#!/usr/bin/python

# Import the otb applications package
import otbApplication

# The following line creates an instance of the GenerateRPCSensorModel application
GenerateRPCSensorModel = otbApplication.Registry.CreateApplication("GenerateRPCSensorModel")

# The following lines set all the application parameters:
GenerateRPCSensorModel.SetParameterString("outgeom", "output.geom")

GenerateRPCSensorModel.SetParameterString("inpoints", "points.txt")

GenerateRPCSensorModel.SetParameterString("map","epsg")

GenerateRPCSensorModel.SetParameterInt("map.epsg.code", 32631)

# The following line execute the application
GenerateRPCSensorModel.ExecuteAndWriteOutput()