mss - User Interface

The executable for the user interface application is “mss”. A short description of how to start the program is given by the –help option. Warnings about CDAT features are due to the NAppy package and can be ignored. The program should open the main window of the user interface, from which you can open further windows, including top view, side view and so on.

Configuration for the user interface is located in “mss_settings.json”. In this file, you can specify, for instance, the default WMS URLs for the WMS client, the size of the local image cache (the MSUI caches retrieved WMS images to accelerate repeated retrievals), or the predefined locations that the user can select in the table view.

A few options influencing the appearance of the displayed plots and flight tracks (colours etc.) can be set directly in the user interface (top view and side view).

Configuration of mss

For storage capabilities mss uses the pyfilesystem <> approach. The default data dir is predefined as a directory: ~/mssdata which is the same as osfs://~/mssdata.

PyFilesystem can open a filesystem via an FS URL, which is similar to a URL you might enter in to a browser. FS URLs are useful if you want to specify a filesystem dynamically, such as in a conf file or from the command line.


FS URLs are formatted in the following way:


The components are as follows:

  • <protocol> Identifies the type of filesystem to create. e.g. osfs, ftp.
  • <username> Optional username.
  • <password> Optional password.
  • <resource> A resource, which may be a domain, path, or both.

Here are a few examples:


Settings file

This file includes configuration settings central to the entire Mission Support User Interface (mss). Among others, define

  • available map projections
  • vertical section interpolation options
  • the lists of predefined web service URLs
  • predefined waypoints for the table view

If you don’t have a mss_settings.json then default configuration is in place.

Store this mss_settings.json in a path, e.g. “$HOME/.config/mss”

The file could be loaded by the File Load Configuration dialog or by the environment variable MSS_SETTINGS pointing to your mss_settings.json.


    "data_dir": "~/mssdata",

    "layout": {
       "topview": [963, 702],
       "sideview": [913, 557],
       "tableview": [1236, 424],
       "immutable": false

    "locations": {
        "EDMO": [48.08, 11.28],
        "Hannover": [52.37, 9.74],
        "Hamburg": [53.55, 9.99],
        "Juelich": [50.92, 6.36],
        "Leipzig": [51.34, 12.37],
        "Muenchen": [48.14, 11.57],
        "Stuttgart": [48.78, 9.18],
        "Wien": [48.20833, 16.373064],
        "Zugspitze": [47.42, 10.98],
        "Kiruna": [67.821, 20.336],
        "Ny-Alesund": [78.928, 11.986]

    "predefined_map_sections": {
        "01 Europe (cyl)": {"CRS": "EPSG:4326",
                            "map": {"llcrnrlon": -15.0, "llcrnrlat": 35.0,
                                    "urcrnrlon": 30.0, "urcrnrlat": 65.0}},
        "02 Germany (cyl)": {"CRS": "EPSG:4326",
                             "map": {"llcrnrlon": 5.0, "llcrnrlat": 45.0,
                                     "urcrnrlon": 15.0, "urcrnrlat": 57.0}},
        "03 Global (cyl)": {"CRS": "EPSG:4326",
                            "map": {"llcrnrlon": -180.0, "llcrnrlat": -90.0,
                                    "urcrnrlon": 180.0, "urcrnrlat": 90.0}},
        "04 Shannon (stereo)": {"CRS": "EPSG:77752350",
                                "map": {"llcrnrlon": -45.0, "llcrnrlat": 22.0,
                                        "urcrnrlon": 45.0, "urcrnrlat": 63.0}},
        "05 Northern Hemisphere (stereo)": {"CRS": "EPSG:77790000",
                                            "map": {"llcrnrlon": -45.0, "llcrnrlat": 0.0,
                                                    "urcrnrlon": 135.0, "urcrnrlat": 0.0}},
        "06 Southern Hemisphere (stereo)": {"CRS": "EPSG:77890000",
                                            "map": {"llcrnrlon": 45.0, "llcrnrlat": 0.0,
                                                    "urcrnrlon": -135.0, "urcrnrlat": 0.0}}

    "crs_to_mpl_basemap_table" : {
        "EPSG:4326": {"basemap": {"projection": "cyl"},
                      "bbox": "latlon"},
        "EPSG:77790000": {"basemap": {"projection": "stere", "lat_0": 90.0, "lon_0": 0.0},
                          "bbox": "latlon"}

   "new_flighttrack_template": ["Kiruna", "Ny-Alesund"],
   "new_flighttrack_flightlevel": 250,

   "default_WMS": [""],
   "default_VSEC_WMS": [""],
   "WMS_login": {
                  "" : ["youruser", "yourpassword"]
   "num_interpolation_points": 201,
   "num_labels": 10,

   "filepicker_default": "default"
Flight track import/export

As the planned flight track has to be quickly communicated to different parties having different desired file formats, MSS supports a simple plugin system for exporting planned flights and importing changed files back in addition to the main FTML format. These filters may be accessed from the File menu of the Main Window.

MSS currently offers several import/export filters in the module, which may serve as an example for the definition of own plugins. The CSV plugin is enabled by default. Enabling the experimental FliteStar text import plugin would require those lines in the UI settings file:

"import_plugins": {
    "FliteStar": ["txt", "", "load_from_flitestar"]

The dictionary entry defines the name of the filter in the File menu. The list specifies in this order the extension, the python module implementing the function, and finally the function name. The module may be placed in any location of the PYTHONPATH or into the configuration directory path.

An exemplary test file format that can be ex- and imported may be activated by:

"import_plugins": {
    "Text": ["txt", "", "load_from_txt"]
"export_plugins": {
    "Text": ["txt", "", "save_to_txt"]

The given plugins demonstrate, how additional plugins may be implemented. Please be advised that several attributes of the waypoints are automatically computed by MSS (for example all time and performance data) and will be overwritten after reading back the file.

Web Proxy

If you are in an area with a very low bandwith you may consider to use a squid web proxy and add those lines in your mss_settings pointing to the proxy server.

  "proxies": {
    "http": "http://yoursquidproxy:3128",
    "https": "http://yoursquidproxy:3128"

Trajectory Tool

For accessing trajectory data based on NASA AMES format you need the nappy python module installed and can configure this view by

  "traj_nas_lon_identifier": ["GPS LON", "LONGITUDE"],
  "traj_nas_lat_identifier": ["GPS LAT", "LATITUDE"],
  "traj_nas_p_identifier": ["STATIC PRESSURE"]


For changing the default cache directory and behaviour to a named directory you can use these parameters. If you use shared directories you may have to solve access rights.

   "wms_cache": "/tmp/.cache/.mss/msui/wms_cache",
   "wms_cache_max_size_bytes": 20971520,
   "wms_cache_max_age_seconds": 432000,

Docking Widgets Configurations


MSS may also roughly estimate the fuel consumption and thus range of the aircraft neglecting weather conditions given a proper configuration file specifying the aircraft performance. Such a file may be loaded using the ‘performance settings’ button in Table View. The aircraft performance is specified using tables given in the JSON format. A basic configuration looks like the following file:

    "name": "DUMMY",
    "takeoff_weight": 91000,
    "fuel": 35000,
    "climb": [[0.00, 0.0, 0.0, 0.0, 0.0]],
    "descent": [[0.00, 0.0, 0.0, 0.0, 0.0]],
    "cruise": [[0.00, 0.00, 400, 2900.00]],
    "_comment1": "_comment fields are just for self-documentation!",
    "_comment2": "takeoff_weight: weight(lbs)",
    "_comment3": "fuel: weight(lbs)",
    "_comment4": "climb/descent: weight(lbs), altitude(ft), duration(min), distance(nm), fuel(lbs)",
    "_comment5": "cruise: weight(lbs), altitude(ft), total air speed(nm/h), fuel flow(lbs/h)"

This example file assumes a constant speed of 400 nm/h and a constant fuel consumption of 2900 lbs/h irrespective of flight level changes. The aircraft weight and available fuel are also given, but these may also be adjusted in the GUI after loading.

The columns of the cruise table are aircraft weight (lbs), aircraft altitude (feet), speed (nm/h), and fuel consumption (lbs/h). MSS bilinearily interpolates in aircraft weight and altitude and extrapolates assuming a constant behaviour outside the given data. The climb table specifies the aircraft performance when climbing up from 0 feet altitude, while the descent table specifies the behaviour when descending down to 0 feet altitude. The column headers are aircraft weight (lbs), aircraft altitude (feet), time spent (minutes), distance required (nm), and fuel consumed (lbs). To compute the required data for a flight level change, a bilinear interpolation in the table for current aircraft weight and the two involved altitudes is performed and the difference of the resulting value is used in the calculation.

Satellite Track Docking Widget

The TopView has a docking widget allowing the visualisation of satellite tracks. A web site to generate the data for such tracks is operated by NASA. The data can be downloaded as ASCII file that can be open by the docking widget. An example file is located at docs/samples/satellite_tracks/satellite_predictor.txt.

KML Overlay Docking Widget

The TopView has a docking widget that allows the visualization of KML files on top of the map. This feature currently does not support all features of KML, for example, external resources such as images are not supported. Some example KML files are located at docs/samples/kml/line.kml and docs/samples/kml/folder.kml.

Remote sensing Docking Widget

The TopView has a docking widget that allows the visualization of remote sensing related features. It may visualize the position of tangent points of limb sounders and can overlay the flight path with colours according to the relative position of sun, moon, and some planets (to either avoid or seek out alignments). Upon first starting the widget, it is thus necessary to download astronomic positional data (see here for more information). This is automatically performed by the skyfield python package, retrieving the data from public sources of JPL and other US services. The data is stored in the MSS configuration directory and may need to update irregularily.

File picker dialogue

MSS supports the use of a general file picker to access locations on remote machines facilitating collaboration on campaigns. To enable this feature apply

"filepicker_default": "fs",

to your configuration file. The allowed values are “qt” for QT-based dialogues, “fs” for fsfile_picker-based dialogues supporting remote locations, or “default” for the default dialogues. The default is currently identical to “qt”, but may change in upcoming releases. The dialogues may also be configured more fine grained with the parameters of ‘filepicker_flightrack for saving and loading flight tracks, ‘filepicker_matplotlib’ for saving figures, “filepicker_config” for loading json configuration files, “filepicker_performance” for loading performance data, “filepicker_satellitetrack” for loading satellite track data, and “filepicker_trajectories” for loading data in the trajectory tool. Additionally, the dialogue type may be configured for each export/import plugin individually by a fourth, optional, parameter.

data dir

With using the “filepicker_default”: “fs” setting you can enable any implemented pyfilesystem2 fs url. Additional to the builtin fs urls we have added optional the webdavfs and sshfs service.

With setting the option “filepicker_default”: “default” you can only access local storages.

"data_dir": "~/mssdata",