5.4.8 Ortho-rectification

This application allows to ortho-rectify optical images from supported sensors.

Detailed description

An inverse sensor model is built from the input image metadata to convert geographical to raw geometry coordinates. This inverse sensor model is then combined with the chosen map projection to build a global coordinate mapping grid. Last, this grid is used to resample using the chosen interpolation algorithm. A Digital Elevation Model can be specified to account for terrain deformations.
In case of SPOT5 images, the sensor model can be approximated by an RPC model in order to speed-up computation.

Parameters

This section describes in details the parameters available for this application. Table 5.28, page 488 presents a summary of these parameters and the parameters keys to be used in command-line and programming languages. Application key is OrthoRectification.




Parameter key

Parameter type

Parameter description




io

Group

Input and output data

io.in

Input image

Input Image

io.out

Output image

Output Image

map

Choices

Output Cartographic Map Projection

map utm

Choice

Universal Trans-Mercator (UTM)

map lambert2

Choice

Lambert II Etendu

map lambert93

Choice

Lambert93

map wgs

Choice

WGS 84

map epsg

Choice

EPSG Code

map.utm.zone

Int

Zone number

map.utm.northhem

Boolean

Northern Hemisphere

map.epsg.code

Int

EPSG Code

outputs

Group

Output Image Grid

outputs.mode

Choices

Parameters estimation modes

outputs.mode auto

Choice

User Defined

outputs.mode autosize

Choice

Automatic Size from Spacing

outputs.mode autospacing

Choice

Automatic Spacing from Size

outputs.mode outputroi

Choice

Automatic Size from Spacing and output corners

outputs.mode orthofit

Choice

Fit to ortho

outputs.ulx

Float

Upper Left X

outputs.uly

Float

Upper Left Y

outputs.sizex

Int

Size X

outputs.sizey

Int

Size Y

outputs.spacingx

Float

Pixel Size X

outputs.spacingy

Float

Pixel Size Y

outputs.lrx

Float

Lower right X

outputs.lry

Float

Lower right Y

outputs.ortho

Input image

Model ortho-image

outputs.isotropic

Boolean

Force isotropic spacing by default

outputs.default

Float

Default pixel value

elev

Group

Elevation management

elev.dem

Directory

DEM directory

elev.geoid

Input File name

Geoid File

elev.default

Float

Default elevation

interpolator

Choices

Interpolation

interpolator bco

Choice

Bicubic interpolation

interpolator nn

Choice

Nearest Neighbor interpolation

interpolator linear

Choice

Linear interpolation

interpolator.bco.radius

Int

Radius for bicubic interpolation

opt

Group

Speed optimization parameters

opt.rpc

Int

RPC modeling (points per axis)

opt.ram

Int

Available RAM (Mb)

opt.gridspacing

Float

Resampling grid spacing

inxml

XML input parameters file

Load otb application from xml file

outxml

XML output parameters file

Save otb application to xml file








Figure 5.28: Parameters table for Ortho-rectification.

Input and output data This group of parameters allows to set the input and output images.

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

Output Image Grid This group of parameters allows to define the grid on which the input image will be resampled.

Elevation management This group of parameters allows to manage 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.

Interpolation This group of parameters allows to define how the input image will be interpolated during resampling. Available choices are:

Speed optimization parameters This group of parameters allows to optimize processing time.

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_OrthoRectification -io.in QB_TOULOUSE_MUL_Extract_500_500.tif -io.out QB_Toulouse_ortho.tif

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 OrthoRectification application 
OrthoRectification = otbApplication.Registry.CreateApplication("OrthoRectification") 
 
# The following lines set all the application parameters: 
OrthoRectification.SetParameterString("io.in", "QB_TOULOUSE_MUL_Extract_500_500.tif") 
 
OrthoRectification.SetParameterString("io.out", "QB_Toulouse_ortho.tif") 
 
# The following line execute the application 
OrthoRectification.ExecuteAndWriteOutput()

Limitations

Supported sensors are Pleiades, SPOT5 (TIF format), Ikonos, Quickbird, Worldview2, GeoEye.

Authors

This application has been written by OTB-Team.

See also

These additional ressources can be useful for further information: