master- generates a base map and projection for a user specified area.
This command is used to generate a base map for image registration (fastreg). The parameters are for the most part self explanatory, but a full list of valid commands can be found in the terascan manual or online man pages.
The most important things to think about are:
Map projection: If the data will be used for mass retrievals, the data should be remapped into an equal area projection (such as lambert azmuthal).
Base map size: The greater the number of lines and samples, the larger the data file will be after it is registered. So, don't make the master file any larger than it needs to be.
Pixel size: This goes along with the base map size. If you are using gac data (which have a lower spatial resolution), a pixel size of 5 is a good choice. If you are using lac 1 or 2 is a good choice. See examples below to see how pixel size affects the area covered by the master file.
To test to see if you have selected the proper area for your master file, display it using the xvu command: Image/Display. Display the filename Master and the variable master, then overlay the coastline on it using xvu command: Overlay/Coast.
Examples
%
master
output file : char(255) ? [Master]
projection : char(
13) ? lambert_azim
center_lat : char( 15) ? 47 N
center_lon :
char( 15) ? 90 W
num_lines : int ? 500
num_samples : int ?
800
pixel_width : real ? [1.1132]
pixel_height : real ?
[1.1132]
rotate_angle : real ? [0]
move_center : char( 3) ?
[no]
This is an example using the same parameters above, except that the pixel size has been changed to 5 km instead of 1.1132.
%
master
output file : char(255) ? [Master]
projection : char(
13) ? lambert_azim
center_lat : char( 15) ? 47 N
center_lon :
char( 15) ? 90 W
num_lines : int ? 500
num_samples : int ?
800
pixel_width : real ? [5]
pixel_height : real ?
[5]
rotate_angle : real ? [0]
move_center : char( 3) ? [no]
This page maintained by Dave Schneider (djschnei@mtu.edu)