Creating the text file for the Script Subset File method

You can create several clip regions from one file by using the Script Subset File method. With this method you create a text file containing the bounds of the clip regions and list the output file names for each clip. Focus uses the text file to automatically produce separate files containing the subset of the data.

When you create the text file, you need to define the bounds of the clip regions and the file names using a particular format, depending on what you selected in the Coordinate Type box on the Clipping/Subsetting window and which file format is selected in the Format box under Output (see Clipping and subsetting images). Each line in the text file contains the data for one clip region. The line is divided into fields separated by spaces. Each field contains a piece of information about the size of the clip region and where to save the file.

Raster extents:

The clip region is defined by identifying upper-left and lower-right pixel and line coordinates. The format for listing the pixel and line coordinates and the file name is as follows:

ul_x   ul_y   lr_x   lr_y   path and filename

For example:

82 115 254 302 C:\Clip1.pix
23 56 87 123 C:\Clip2.pix

Geocoded extents:

The clip region is defined by identifying the georeferenced coordinates of the upper-left and lower-right corners. The format for listing the coordinates is as follows:

ul_x ul_y lr_x lr_y path and filename

For example:

433000.000 5876000.000 443000.000 5873000.000 C:\Clip1.pix
432567.973 5876348.000 435685.342 5874343.341 C:\Clip2.pix

Long/Lat extents:

The clip region is defined by identifying the geographic coordinates of the upper-left and lower-right corners. The extents can be defined suing a number of different formats such as the following example. For more information, see the online help for LONG/LAT INPUT under Projection Reference in the Technical Reference.

ul_x   ul_y   lr_x   lr_y   path and filename

For example:

117d46'10"W 33d44'55"N 117d40'10"W 33d38'55"N C:\Clip1.pix
117d35'22"W 33d40'30"N 117d30'22"W 33d33'30"N C:\Clip2.pix

Raster offset/size:

The clip region is defined by identifying the pixel and line coordinates of the upper-left corner and providing the number of pixels in width and the number of line in length.

ul_x ul_y width height path and filename

For example

34 56 400 400 C:\Clip1.pix
135 127 300 100 C:\Clip2.pix

Geocoded offset/size:

The clip region is defined by identifying the georeferenced coordinates of the upper-left corner and providing width and length in the units of measurement of the input's coordinate system.

ul_x ul_y width height path and filename

For example:

433000.000 5876000.000 300.000 300.000 C:\Clip1.pix
32567.973 5876348.000 1500.000 2500.000 C:\Clip2.pix