CDFORMOSAT

Description

CDFORMOSAT reads FORMOSAT imagery from a TIFF-format CD when satellite orthorectification is required. CDFORMOSAT automatically creates a PCIDSK file, reads all the requested imagery channels from CD, and saves the satellite path information in a segment. The output file from CDFORMOSAT is used as input to CATALYST Professional OrthoEngine.

Parameters

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

Name	Type	Caption	Length	Value range
FILI *	str	Input file name	1 -
FILO *	str	Output file name	1 -
LINKFILE	str	Create linked file (NO/YES)	0 - 3	YES, NO Default: NO
CDIC *	List[int]	CD Input channels or layers	1 - 16
TEX1	str	Descriptive text	0 - 384

* Required parameter

Parameter descriptions

FILI

Specifies the path and file name of the input TIFF file.

FILO

Specifies the name of the PCIDSK file that will contain the output satellite CDFORMOSAT image layer(s). This file will be 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 FILO in which the image channel is linked to the original FILI. 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.

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

Details

CDFORMOSAT is part of the satellite orthorectification component. It reads a FORMOSAT TIFF-format CD when satellite orthorectification is required. The corresponding metadata file must also exist in the same directory. CDFORMOSAT automatically creates a PCIDSK file, reads all the requested imagery channels from CD, and saves the satellite path information in a segment. Output from CDFORMOSAT is used with CATALYST Professional OrthoEngine

CDFORMOSAT 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.

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 CDFORMOSAT. If LINKFILE is set to YES, the image channel is not created; instead, it is linked to the image channel of FILI. For rotated or flipped images, LINKFILE is ignored.

Example

For a FORMOSAT product on TIFF-format CD, perform an orthorectification on the data. Extract channel 1 and store it in the file formosat.pix.

from pci.cdformosat import cdformosat

fili = 'RS2_100257000_1A_0001_PAN.tif'
filo = "formosat.pix"              # output file name
linkfile = "NO"
cdic = [1]                      # input channel number
tex1 = "Richmond Hill, Canada"

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

After the CD has completed reading, the text report is displayed.

The file formosat.pix can now be used as input, along with collected ground control points, to CATALYST Professional OrthoEngine.

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.)