The PATHS section of the configuration file allows the user to specify the location of additional files and/or data that will be utilized during the simulation. When DIRSIG starts, these paths are initialized to default values based on the installation configuration, thereby providing the user access to the distributed material, emissivity, weather databases, etc. The default values for the directory paths are listed in Table 32-1.
Table 32-1. List of the variables that can be set in the PATHS section
| Variable Name | Default Value | Description | |
| ABSORPTION_PATH | DIRSIG_HOME/lib/data/absorption | Directory containing plume gas absorption files | |
| EMISSIVITY_PATH | DIRSIG_HOME/lib/data/emissivity | Directory containing emissivity files | |
| EXTINCTION_PATH | DIRSIG_HOME/lib/data/extinction | Directory containing extinction files | |
| GDB_PATH | DIRSIG_HOME/lib/data/gdb | Directory containing geometric database files | |
| ODB_PATH | DIRSIG_HOME/lib/data/odb | Directory containing object/scene database files | |
| WEATHER_PATH | DIRSIG_HOME/lib/data/weather | Directory containing weather files | |
| TAPE5_PATH | DIRSIG_HOME/lib/data/tape5 | Directory containing input files | |
| MAPS_PATH | DIRSIG_HOME/lib/data/maps | Directory containing mapping images | |
| SOURCES_PATH | DIRSIG_HOME/lib/data/sources | Directory containing source intensity functions | |
| RESPONSE_PATH | DIRSIG_HOME/lib/data/responses | Directory containing sensor response files | |
In some cases, the user may wish to use their own weather data, material databases, sensors, etc. In these cases, the user can specify the appropriate path to their data by setting the corresponding variable in the configuration file. The section from the example CFG file is included below:
#
# The PATHS section sets the pathnames to spectral data, material databases,
# material and texture maps, man-made sources, pre-configured sensors,
# detector responses, etc.
#
PATHS {
EMISSIVITY_PATH = /home/scott/project/lib/emissivity
EXTINCTION_PATH = /home/scott/project/extinction
MATERIAL_PATH = /home/scott/project/lib/material
}
In this case, the EMISSIVITY_PATH, EXTINCTION_PATH and MATERIAL_PATH variables were set to override the default directory paths and point to a project directory.
Important change as of Release 3.1.1. GDB_PATH variable was introduced in Release 3.1.1 to allow the user to accumulate geometric database files in one location. The affects this change has on CFG files distributed and used with Release 3.1 is covered in Section 32.2.
If a user has developed a large set of supplemental data and wishes to utilize the same overrides for the PATHS section for all their simulations, then the user may consider making a file with their own PATHS section that is included in all of their configuration files. For example, this author may be experimenting with some new materials for a special project. Rather than put these invalidated materials in the main material database, you might keep them in a separate directory called project. You could then create a file in this directory called .dirsig-paths which looks like:
PATHS {
EMISSIVITY_PATH = /home/scott/project/lib/emissivity
EXTINCTION_PATH = /home/scott/project/extinction
MATERIAL_PATH = /home/scott/project/lib/material
}
In each DIRSIG configuration file, simply include the following file using the INCLUDE_FILE feature:
DIRSIG_CFG
#use my own paths for this project
INCLUDE_FILE = /home/scott/project/.dirsig-paths
By doing this, DIRSIG will look for material, emissivity and extinction files in your project directory rather than in the DIRSIG install directory. All the other paths will retain their default values. If you need to change the location of these database directories, then I only have to edit the .dirsig-paths file, and all of your simulations that include this file will be updated the next time DIRSIG is run.