CDLAND7

Description

CDLAND7 reads LANDSAT HDF, Tiff, Fast, or NLAPS format CD when satellite orthorectification is required. This program also supports Landsat 5 in TIFF format. CDLAND7 automatically creates a PCIDSK file, reads all the requested imagery channels from CD, and saves the satellite path information in a segment.

Parameters

cdland7(filehd, file, cdic, tex1)

Name	Type	Caption	Length
FILEHD*	str	Input header file	1 -
FILE*	str	Output file name	1 -
CDIC*	List[int]	CD Input channel(s)	1 - 16
TEX1	str	Descriptive text	0 -

* Required parameter

Parameter descriptions

FILEHD

Specifies the full path and file name of the header.

Input data files have various formats:

LANDSAT HDF: header file contains the characters "HDF" in upper or lowercase.
TIFF: name of any TIFF file
Fast: name of the header file
NLAPS: name of the header file

FILE

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

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.

Note:

When importing Landsat 7 data, you cannot mix channels of different resolutions; for example, you cannot mix panchromatic and multispectral data in the same file. Channels of different resolutions must be imported as separate files.

Landsat 7 data contains two band 6 files: low gain and high gain. Specify CDIC=61 for low gain and CDIC=62 for high gain.

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

CDLAND7 is part of the satellite orthorectification component. It reads a LANDSAT HDF, TIFF, Fast, and NLAPS format CD when satellite orthorectification is required. CDLAND7 also supports Landsat 5 in TIFF format. CDLAND7 automatically creates a PCIDSK file, reads all the requested imagery channels from the CD, and saves the satellite path information to one or two segments.

The USGS data center provides access to different levels of geodetic processing and product types. CDLAND7 supports the following formats:

1G level in HDF, TIFF, Fast, or NLAPS format

Note: CDLAND7 does not support 0R and 1R processing levels.

CDLAND7 extracts from the CD the geographic coordinates of the scene center and the four corner points. The corner points are extracted only if they are UTM coordinates; otherwise, the LAT/LONG coordinates are used to calculate the equivalent UTM coordinates. The values are stored in the output orbit segment. These coordinates 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.

The FILE (Output) parameter specifies the name of the PCIDSK file that holds the imagery and orbital information obtained from the CD. This file is automatically created with the dimensions required to hold all of the requested data. Sufficient disk space is required before running CDLAND7.

Example

The current working directory contains the Landsat 7 level 1G product in the HDF format, with the header file L71041034_03419990702_HDF.L1G. All 30m channels of the image (1,2,3,4,5 and 7) are imported to the first PCIDSK database, the two 60m are imported to the second PCIDSK database, and the 15m panchromatic channel is imported to the third database.

from pci.cdland7 import *

# load the algorithm

# set the input file name
filehd = "L71041034_03419990702_HDF.L1G"    # input Landsat 7 data set

# import the 30 m channels
file = "L7_30m.pix"    # imported 30 m channels in PCIDSK database
cdic = [1,-5,7]    # image channels to import
tex1 = "Geology Sample, 30 m."    # image description
cdland7 (filehd, file, cdic, tex1)

# import the 60 m channels
file = "L7_60m.pix"    # imported 60 m channels in PCIDSK database
cdic = [61,62]
tex1 = "Geology Sample, 60 m."
cdland7 (filehd, file, cdic, tex1)

# import the 15 m channel
file = "L7_15m.pix"    # imported 15 m channel in PCIDSK database
cdic = [8]
tex1 = "Geology Sample, 15 m."
cdland7 (filehd, file, cdic, tex1)

Acknowledgements

PCI Geomatics acknowledges the assistance of Dr. Thierry Toutin for this software.

References

Toutin, Th. "Analyse math\u00c3\u00a9matique des possibilit\u00c3\u00a9s cartographiques du syst\u00c3\u00a8me SPOT". Th\u00c3\u00a8se de Docteur-Ing\u00c3\u00a9nieur en Sciences G\u00c3\u00a9od\u00c3\u00a9siques, ENSG, Paris, France, 1985. pp1 -163.

Toutin, Th. and Carbonneau Y. "La multi-st\u00c3\u00a9r\u00c3\u00a9oscopie 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.)

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