Keywords - Gui,
graphical user interface, Hirlam, Weptel, Dem, Dream, numerical
models, weather presentation, environment, pollution.
1. Introduction
In the context of the WEPTEL project, the KNMI develops
a GUI, a graphical user interface for the
weather forecast model HIRLAM, and the environmental pollution
models DEM, danish eulerian model, and DREAM,
danish rimpuff and eulerian accidental
release model, both operational at DMU, the Danish WEPTEL
partner; or possibly other models coupled to HIRLAM.
DEM is a simulation model to predict the spreading,
concentration and distribution of chemical pollutants in the atmosphere
in cases of episodic pollution events. DREAM does the same as
DEM for calamities, where the release of the pollutant is much
more localised. Both these models need atmospheric parameters
like meteorological fields in order to be able to produce a prediction,
at the time of pollutant releases as well as in the near future.
The coupling with HIRLAM is of no further interest for this article,
but has been tested satisfactory.
This article will start with a short introduction
of WEPTEL, and the role of the GUI within this context. Finall,
the functionality as a user interface for HIRLAM will be treated
in more detail.
WEPTEL, an acronym for innovative WEather
Presentation on TELevision, is an EC funded Esprit
project, number 22727. For more information, see the WEPTEL homepage
at URL: http://www.wi.leidenuniv.nl/CS/HPC/weptel.html.
The GUI performs a central role in the following institutions and operators:
The GUI will be able to :
The models can be run on different hosts in different locations. This is the most natural setup: besides the models themselvels, also the expertise of the institutions involved is needed for interpretation, analysis, diagnosis and validation of requests and results.
A visualisation tool (VE), also developed in the context of WEPTEL, will process validated model output at the TV station to finally obtain pictures and animations in broadcasting quality, ready to go on air. It has the same layout, look-and-feel as the GUI, and the operator can easily switch between the two interfaces. This is one core objective of the project: improve weather presentations on television by improving visualisations of numerical model output using state-of-the-art techniques. The other core objective is to combine weather forecast presentations with information about environmental pollution. This requires a tight coupling between the forecast and pollution models. Especially in the case of a calamity this imposes constraints on the timeliness of model output.
The HDF file format from NCSA was accepted as the
standard for data transfer between the different models and the
GUI. HDF (hierarchical data format) can comprise
multi-dimensional scientific data sets, different types of raster
images and multi-dimensional tabular data sets. As some models
read or produce the WMO-GRIB file format, KNMI has developed file
conversion software to convert between GRIB and HDF (tested for
SGI and CRAY platforms).
The GUI is especially designed to be used for definition
of dedicated runs, if desired for e.g. seasonal activities or
calamitous or episodic pollution events. These reruns will typically
be at higher spatial resolutions and over smaller areas as compared
to the operational runs. In order to be able to run HIRLAM at
higher resolutions at the KNMI, from 55 km gridcells to 5.5 km
gridcells, new physiological data sets have been implemented (by
Han The).
A common situation is that the TV station receives
HIRLAM model output on an operational basis. The model run definition
is fixed by contract: the area, the parameters, the resolution,
the projection, etc. The presenter may occasionally want to present
extra information. Some examples: weather forecast for favourable
holliday destinations (summer and winter), up to date information
and forecast about an accidental calamitous release, information
about episodical air pollution showing higher levels than normal,
more detailed weather forecast of a smaller sub-area in higher
resolution to high-light interesting weather phenomena, etc.
Types of (re)runs requested by presenter using the GUI :
To deal with different user levels, the functionality
is adapted and controlled by passwords. Different users have different
access rights to the full functionality (e.g. the presenter cannot
submit a batch job to start a rerun, but he/she can provide all
the necessary parameters for the request in the form of a file
which only has to be reloaded by the meteorologist to check before
submitting the computational job).
| Operator | Software | Actions | Data Files | Transfer to |
| presenter | GUI | specify/request | script files | meteorologist
environmentalist |
| meteorologist | GUI
HIRLAM GUI | validate/submit
run diagnose |
script files
HDF files HDF files |
HIRLAM
GUI presesenter environmentalist |
| environmentalist | GUI
DEM/DREAM GUI | validate/submit
run diagnose/validate | script files
HDF files HDF files | DEM/DREAM
GUI presenter |
| presenter | GUI
VE |
diagnose/validate
visualise process present | HDF files | VE |
Table 1. Flow of events, starting and ending with the presenter.
3. GUI as user interface for HIRLAM
The GUI has been designed and partly implemented
using OSF/Motif style and X11/Xlib libraries. The current version
runs on a SGI workstation under operating system IRIX 6.4. After
finalization, porting to other platforms is likely, but a higher
priority has the implementation as part of a browser (as java
console or plug-in).
The look-and-feel is like a console: the main window
consists of a fixed drawing area, with buttons beside and below
it. It takes over the full screen: when not iconized, it pops
to full size and is not resizable: all other windows at the time
of start-up are hidden but still keep running. Only three user
definable buttons (invoking a shell script) can start other applications,
so that the user can simultaneously operate the GUI and e.g. an
editor. Below the drawing area a small button bar is constructed
for heavily used functions (switch on/off different layers, change
the map projection, zooming functions, cut/copy/paste/delete).
For speed considerations the drawing area has a pop-up menu attached
to it, to quickly switch between different modes (zoom/pan, define
area, full-screen viewing). For uniformity according to OSF/Motif
style rules, the main window comprises an optional pull-down menu-bar
at the top, duplicating the functionality of the console buttons.
Very little use has been made of pop-up windows to avoid a messy
screen full of windows. Only for messages, warnings and errors,
which have to be acknowledged by the user, a window pops up. Below
the button bar an area is reserved for the dialogs, all consisting
of frames with fixed positions, shown at user demand by activating
console buttons.
The drawing area can be switched to full screen size.
It then takes over the screen, and no other applications can be
operated. It is intended for visual analysis after the map has
been constructed in normal mode, only some zoom/pan functions
and definition of model-run areas is accessible (and of course
switch back to normal mode).
As visualisation and diagnostic tool the display and manipulation of HDF files is implemented. A 2-dim slice through a 3-dim data set can be selected and displayed as a raster image :
Still under development :
For orientation, the world vector shoreline database is used in different selectable generalizations. The map projection of the display can be selected as:
Flexible area selection is implemented in the define area mode:
Still under development:
Planning of further implementation of functions, in order of priority :