CDOV

Description

Parameters

cdov(fili, filo, linkfile, cdic, modeltyp, tex1)

Parameter descriptions

FILI

Specifies the full path and file name of the input TIFF or NITF file.

FILO

Specifies the name of the output file that will receive the processed data. The output file is created automatically and must not already exist.

LINKFILE

Instead of creating a new PCIDSK FILO to read the data from FILI, this parameter will create an output in which the image channel is linked to the original imagery. The orbital segment will still be created in FILO. The default value is NO.

CDIC

Specifies the list of channels or layers to read from the CD. Up to 16 channels may be specified.

For each channel, a corresponding channel is created in the output PCIDSK file. Duplicate channels are not allowed.

If this parameter is not specified, all channels will be read from the file.

MODELTYP

Specifies the type of model segment to create. Either an orbit segment or a RPC segment will be created.

The following options are supported:

• RPC Create a RPC math model segment.
• ORBIT Create an orbit segment for use with the toutin math model.

TEX1

Optionally specifies a line of text that describes the file. Typically, this contains information that identifies the location of the data and the CD reference number.

If TEX1 (File Description) is not specified, the File Header fields in the generated output PCIDSK image database hold the following information:

• FH5 receives the tape ID, satellite sensor, and satellite track
• FH7.1 receives the acquisition date and scene center (longitude and latitude, in decimal degrees)
• FH7.2 is empty

Return Value

Returns: execution status

Type:  PCI_INT

The return value is 0. This function returns only if it executes successfully; otherwise, it throws an exception instead of returning.

Details

CDOV is part of the satellite orthorectification component. It reads an OrbView TIFF or NITF format CD when satellite orthorectification is required. The corresponding metadata file must also exist in the same directory. CDOV automatically creates a PCIDSK file, reads all the requested imagery channels from CD, and saves the satellite path or RPC information in a segment.

The PVL file and the input TIFF file must reside in the same directory.

CDOV extracts from the CD the geographic coordinates of the scene center and the four corner points. The values are stored in the output orbit segment. These points can be used as ground control point (GCP) input for an approximate correction, which is useful when GCPs are unavailable for an area. Note, however, that using geographic coordinates may not produce very accurate results. To ensure an accurate calculation, a sufficient number of GCPs must be used for each scene or block of scenes.

If the LINKFILE parameter is set to NO, the output file is automatically created with the dimensions required to hold all of the requested data. Ensure that sufficient disk space is available before running CDOV. If LINKFILE is set to YES, the image channel is not created; instead, it is linked to the image channel of FILI.

Example

The user has received a OrbView product in Tiff or NITF format CD and wishes to perform orthorectification on the data. The user wishes to extract channel 1 and store them in the file "orbview.pix".

from pci.cdov import cdov

fili = "3V031226P657281A0010.tif"
filo = "orbview.pix"				# output file name
linkfile = "NO"
cdic = [1]					# input channel number
tex1 = "Richmond Hill, Canada"

cdov(fili, filo, linkfile, cdic, tex1)

References

Toutin, Th. "Analyse mathématique des possibilités cartographiques du système SPOT". Thèse de Docteur-Ingénieur en Sciences Géodésiques, ENSG, Paris, France, 1985. pp1 -163.

Toutin, Th. and Carbonneau Y. "La multi-stéréoscopie pour les corrections d'images SPOT-HRV", Canadian Journal of Remote Sensing, Vol. 15, No. 2 (September 1989) p110. (Also available in English from the Canada Centre for Remote Sensing.)

Holekamp, K., "Radiometric Characterization of the IKONOS, QuickBird, and OrbView-3 Sensors", Civil Commerical Imagery Evaluation Workshop, Laurel, Maryland, USA, March 15, 2006. (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070038235_2007037712.pdf).