RTM configuration

The RTM configuration allows users to update basic information about the installed atmospheric RTM. After the selection of a RTM through the Select RTM pop-up menu (top-left), the user can introduce/modify the default values of:

  • The RTM version number (e.g., 2.1 for 6SV v2.1) by filling the Version text box. This information is not currently needed to run the atmospheric RTM.
  • The path and name for the RTM source file by filling the corresponding text box. This can be done by typing the path and name of the atmospheric RTM executable (e.g., C:\ALG\third_party_sw\6SV2.1\sixsV2.1.exe) or by pressing on the button and select the executable file.
  • The operation mode options (bottom-left) allow users to select among different RTM execution modes, thus with different RTM output data:

    • The Transfer Functions option allows generating the so-called atmospheric transfer functions for the selected RTM. These functions include typical standard outputs of atmospheric RTMs such as path radiance, transmittance or at-surface irradiance. Use the transfer Functions mode for applications such as forward simulation or atmospheric correction.
    • The At-sensor Radiance option runs the selected RTM in a forward mode, calculating the radiance reaching the sensor. In this mode, in addition to atmospheric, geometric and spectral configuration, users will also define the surface properties (e.g., reflectance, fluorescence, temperature, emissivity) and cloud properties. Not yet implemented
    • The Transmittance option runs the selected RTM in transmittance mode and stores the direct target-to-sensor transmittance for available gasses.

    Notice that not all these operation modes are available for all atmospheric RTMs. Particularly, the transmittance mode is only available for MODTRAN5 and MODTRAN6. To add a new operation mode, select it from the operation mode options and click on the > button. To remove an operation mode, select it from the operation mode (implemented) list and click on the < button.

    After introducing this information, click on the Apply or Apply and Close buttons. This will update the RTM configuration file (RTMconf.xml) stored in the ALG Conf subfolder. Notice that these changes cannot be undone.

    The user can add new atmospheric RTMs into the RTMconf.xml file by selecting the Add new RTM on the Select RTM pop-up menu. In addition to the basic RTM configuration explained in the above paragraphs, the Add new RTM option will display a New RTM name text-box (top-right) where the user should introduce the name of the new atmospheric RTM.

    Notice that this functionality does not implies that the added RTM will run in ALG. For users willing to implement new atmospheric RTMs into ALG, please contact us at alg.toolbox@gmail.com.

    The user can also remove any RTM from the RTMconf.xml file by selecting it from the Select RTM pop-up menu and pressing the Remove RTM button. A warning dialogue window will appear to confirm the removal of the selected RTM.