WorldWeatherSymbols usage in MapServer

build.sh

#!/bin/sh

WMO_SYMBOLS_DIR=build/WorldWeatherSymbols

if [ ! -d $WMO_SYMBOLS_DIR ]; then
    echo "Downloading WMO World Weather Symbols"
    git clone https://github.com/OGCMetOceanDWG/WorldWeatherSymbols.git $WMO_SYMBOLS_DIR

    echo "Converting all symbols to PNG"
    $WMO_SYMBOLS_DIR/scripts/wws_manage.sh png

    echo "Rotating missing wind arrows image 90 degrees CCW"
    convert $WMO_SYMBOLS_DIR/png/WeatherSymbol_WMO_WindArrowMissing_99.png -rotate -90 $WMO_SYMBOLS_DIR/png/WeatherSymbol_WMO_WindArrowMissing_99.png

    echo "Rotating north wind arrows images 90 degrees CW"
    for sym in `find $WMO_SYMBOLS_DIR/png -type f -name "WeatherSymbol_WMO_WindArrowNH*.png"`
    do
        convert ${sym} -rotate 90 ${sym}
    done

    echo "Rotating south wind arrows images 90 degrees CCW"
    for sym in `find $WMO_SYMBOLS_DIR/png -type f -name "WeatherSymbol_WMO_WindArrowSH*.png"`
    do
        convert ${sym} -rotate -90 ${sym}
    done

else
    echo "$WMO_SYMBOLS_DIR already exists"
fi

steps.txt

Notes:

- two columns need to exist in data table
 - WIND_DIRECTION_COLUMN: this is the angle, in degrees, which drives the symbol rotation
 - WIND_SPEED_SYMBOL_ABSOLUTE_FILEPATH: this is managed in the data table as an easy means to specify the symbol as driven from the data. This requires a pre-processing step to set the filepath column value based on the wind speed value of an observation.  We bind the SYMBOL object like this to save from specifying numerous class defs

Steps:

- build the WorldWeatherSymbols PNGs (build.sh)
 - FYI once the symbols are converted in SVG (see https://github.com/OGCMetOceanDWG/WorldWeatherSymbols/issues/7), the rotation steps in build.sh will not be required
- add wind_speed-class.inc to the LAYER def

wind_speed-class.inc

## STYLES=wind_speed
CLASSGROUP "wind_speed"

 CLASS #
  NAME "Wind Speed (km/h)"
  GROUP "wind_speed"
  TEXT ""
  STYLE
   ANGLE [WIND_DIRECTION_COLUMN]
   SYMBOL [WIND_SPEED_SYMBOL_ABSOLUTE_FILEPATH]
   SIZE 30
  END
  LABEL
   TYPE truetype
   FONT arial
   SIZE 8
   OUTLINECOLOR 255 255 255
   OUTLINEWIDTH 2
   COLOR 46 46 46
   POSITION AUTO
   MAXSCALEDENOM 11000000
  END
 END