Current Weather Project
The aim of the project was to develop an XML data exchange format to (1) transfer a weather observation that could include both automatically and manually observed data, and (2) display the combined weather observation on a webpage using XSL transformation (XSLT).
The new XML data exchange format would be based on an experimental data exchange format for automatic weather data. The display would ideally include a coded SYNOP message and graphical representation of the weather data in the form of a station weather plot.
Project Stages
The following stages were identified as key elements of the project:
- Match variables with the required station details, automatic weather data and manually observed weather data,
- Create the XML template file and XML Schema Definition (XSD) document to specify the structure of the new Current Weather Document,
- Investigate the feasibility of creating a station weather plot from the automatic and manual weather data,
- Create graphics to represent the automatic and manual weather data,
- Create a style document (XSL document) to specify how the XML data would be displayed in a web browser,
- Create education pages describing a Station Weather Plot, SYNOP Code Form and Weather Symbols and Code Figures.
Project Variables
The variables used in this project are listed below. Select a variable to view the complete XML element definition, including: the element name and description, the expected data type, the permitted values where explicitly defined, and whether the element is mandatory or optional.
The variables in the template file are replaced with the equivalent output tags from the PWS software. If a variable has no equivalent output tag from the PWS software, the options are to: (1) create a user-defined output tag for the PWS software containing the appropriate value, or (2) replace the variable in the template file with the appropriate value. If an optional variable is permanently unavailable, the template file is edited as per this example - replace <foo>%variable%</foo> with <foo />.
- %1hr_rain%
- %24hr_rain%
- %24hr_time%
- %absolute_pressure%
- %altitude%
- %country%
- %evap%
- %evap_sensor%
- %high_cloud_type%
- %horizontal_visibility%
- %international_date%
- %latitude%
- %local_time_manual%
- %longitude%
- %low_cloud_type%
- %lowest_cloud_amount%
- %lowest_cloud_height%
- %maximum_temperature%
- %middle_cloud_type%
- %minimum_temperature%
- %outside_dewpoint%
- %outside_temperature%
- %outside_humidity%
- %pressure_change%
- %pressure_trend%
- %station_name%
- %past_weather%
- %pres_sensor%
- %pressure_change_period%
- %present_weather%
- %program_name%
- %program_version%
- %rain_sensor%
- %rain_today%
- %relative_pressure%
- %station_identifier%
- %sun_sensor%
- %sunshine%
- %temp_sensor%
- %timezone%
- %total_cloud_amount%
- %unit_dewpoint%
- %unit_evap%
- %unit_height%
- %unit_humidity%
- %unit_pressure%
- %unit_rain%
- %unit_sun%
- %unit_temperature%
- %unit_wind_speed%
- %wind_direction_points%
- %wind_direction_degrees%
- %wind_gust%
- %wind_sensor%
- %wind_speed%
- %windchill%
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XML Schema Definition
View the XSD diagram for this project.
Weather Graphics
More than 500 graphics were created for the graphical representation of the weather data. This includes over 400 graphics to replicate the WMO weather symbols, including symbols for: total cloud cover, types of low cloud/middle cloud/high cloud, wind direction & wind speed both separately and combined, past weather, present weather and pressure trend, and about 100 graphics to show descriptive text corresponding to the WMO code figures for visibility and base of lowest cloud.
More information: weather symbols and code figures
Data Display
The combined weather observation can comprise a mix of raw values and WMO code figures. Some of the raw values are plotted as they are reported, whilst others must be coded for the purposes of plotting. All of the code figures, with the exception of visibility, are represented by the appropriate weather symbols in the station plot.
The evolution of the XSL document that specifies how the XML data are displayed in a web browser is described below:
- Version 1.0: based entirely on the raw observed values of mean sea level pressure, amount of pressure change, rainfall and wind speed.
- Version 1.1: added support for standalone graphics representing wind speed.
- Version 1.2: added support for encoded values of mean sea level pressure, amount of pressure change and rainfall.
- Version 2.0: introduced programming variables to support graphics representing the combined wind speed and direction in the station plot.
- Version 2.1: greater use of programming variables to remove duplicated sections of code.
- Version 2.2: added support for alternative units of wind speed and a wind speed conversion to knots.
- Version 2.3: added a time conversion to UTC and enhancements to the display.
- Version 2.4: added a display timeout for an "old" manual observation.
- Version 2.4.1: minor fix to the UTC conversion.
- Version 2.5: added time descriptors for AEST and AEDT, plus hourly SYNOP report.
- Version 2.6: added support for future elements - amount of evaporation and duration of sunshine.
Project Status
See an example of a full manual and automatic observation using the latest XSL version with plain vanilla styling.
This 2020 project successfully achieved its aims and is operational. View our current weather data on the TrugWX Live Weatherwall, which includes an occasional manual weather report. The project remains open for possible further development.
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