IHR

Description

IHR extracts data from a PCIDSK file header and georeferencing layer, and writes the data values to the output parameter(s).

Parameters

ihr(file, imstat)

Name	Type	Caption	Length	Value range
FILE *	str	Input file name	1 -
IMSTAT	List[float]	Image Statistics	0 - 15

* Required parameter

Parameter descriptions

FILE

Specifies the name of the PCIDSK image file from which header and georeferencing data are to be extracted.

IMSTAT

Header and georeferencing data extracted from the database file are saved in the IMSTAT output parameter for use by other algorithms. After IHR has completed running, IMSTAT contains the following values:

first IMSTAT array element : number of pixels per line (width) on each image channel
second IMSTAT array element : number of scan lines (height) on each image channel
third IMSTAT array element : total number of image channels in the input file
fourth IMSTAT array element : number of unsigned 8-bit image channels
fifth IMSTAT array element : number of signed 16-bit image channels
sixth IMSTAT array element : number of unsigned 16-bit image channels
seventh IMSTAT array element : number of 32-bit real image channels
eighth IMSTAT array element : number of active segments in the input file
ninth IMSTAT array element : X (horizontal) pixel size, in the reported units
tenth IMSTAT array element : Y (vertical) pixel size, in the reported units
eleventh IMSTAT array element : georeferencing units (0=PIXEL, 1=UTM, 2=METER, 3=LONG/LAT, 4=other, -1=error)
twelfth IMSTAT array element : georeferenced upper-left horizontal (X) position of the input image
thirteenth IMSTAT array element : georeferenced upper-left vertical (Y) position of the input image
fourteenth IMSTAT array element : georeferenced lower-right horizontal (X) position of the input image
fifteenth IMSTAT array element : georeferenced lower-right vertical (Y) position of the input image

Details

IHR reads header and georeferencing data from the specified input file (FILI), and saves the retrieved data to the IMSTAT parameter.

Examples

Get database header and georeferencing data from the demo database file irvine.pix, and print the values.

from pci.ihr import ihr

file='irvine.pix'
imstat=[]

ihr( file, imstat )

print(imstat)

IMSTAT  - Image Statistics  >     512      512       10        9
                                    1        0        0       32
                                   30       30        1   428720
                              3734400   444080  3719040

The code shown below calculates the georeferenced location of the center of a specified database position (X,Y). Scaling factors (XSCALE,YSCALE) are calculated, given georeferenced locations of the upper-left and lower-right corners of the database, and the number of pixels and lines on the database.

from pci.ihr import ihr

def get_location(file_, x, y):
    imstat=[]
    ihr( file_, imstat )
    xscale=(imstat[13]-imstat[11]) / imstat[0]
    yscale=(imstat[13]-imstat[11]) / imstat[1]

    print('Georeferenced X position  = ' + imstat[11]+xscale*(x-0.5))
    print('Georeferenced Y position  = ' + imstat[12]+yscale*(y-0.5))

Note: When georeferencing units are UTM or METER, the pixel size (IMSTAT(9),IMSTAT(10)) equals the absolute value of the scaling factors (XSCALE,YSCALE).

Environments	PYTHON :: EASI :: MODELER
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IHR

Read database image header

Description

Parameters

Parameter descriptions

Details

Examples