CDMERIS

Description

Parameters

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

Parameter descriptions

FILI

Specifies the full path and file name of the MERIS-format file to be processed. The input file has an .N1 extension.

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 file in which the image channel is linked to the original imagery channel. 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 9 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.

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.

Details

CDMERIS is part of the satellite orthorectification component. It reads the MERIS format CD when satellite orthorectification is required. CDMERIS automatically creates a PCIDSK file, reads all the requested image channels from CD, and saves the satellite path information in a segment.

CDMERIS 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 CDMERIS. If LINKFILE is set to YES, the image channel is not created; instead, it is linked to the image channel of FILI. For stereo data, LINKFILE is ignored and a new file is created because rotation is required when reading the data.

Example

The user has received a MERIS 1B product CD and wishes to perform orthorectification on the data. The user wishes to extract channel 1 and store the data in the file "meris.pix".

from pci.cdmeris import cdmeris

fili = "MER_RR__1PNPDK20020920_175243_000002702009_00356_02915_0639.N1"	# input image file
file = "meris.pix" 	# output image file
cdic = [1] 	# channel number 1
tex1 = "Richmond Hill, Canada"

cdmeris (fili, file, cdic=cdic, tex1=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.)