WeatherZero forecast service

This extension provides an easy way to get weather forecast data for a set of latitude and longitude points, for a given timespan. It is a wrapper for the NWS (National Weather Service) SOAP weather service: http://www.weather.gov/xml/. The extension creates the SOAP request to the NWS service and uses a SAX parser to perform the tasks described in this article.

Adding weatherZero to your project

To use the weatherZero extension, add it to your project. You can do this with the Project Zero tooling by editing your config/ivy.xml file. Add the weatherZero library to your dependencies. If you do not have the library installed, it is downloaded automatically when you save the ivy.xml file or the next time your resolve your project.

Requesting weather information

com.tripwx.forecasts.WeatherForecastRetriever:

public static Object getWeatherForecast(List pointsData, Date startTime, Date endTime)

Using the parameters

Use the following parameters for this call:

pointsData

This provides the List of Map objects with keys lat, lng, and optionally, time. The lat and lng pairs represent the decimal coordinates for each point, latitude and longitude, where a forecast is to be provided. The time object is a placeholder that specifies the time you want a forecast at each point, as shown in the following example:

     [
         {"lat": 35.77975, "lng": -78.64341, "time": 1201030680000}, 
         {"lat": 36.83412, "lng": -75.30676000000001, "time": 1201030680000}
         {"lat": 35.9767, "lng": -79.71538, "time": 1201030680000}
     ]
     

startTime

This is the Date object representing the beginning (time and date) of the timespan for which weather information is to be obtained for each of the specified (latitude and longitude pair) points.

endTime

This is the Date object representing the end (time and date) of the timespan for which weather information is to be obtained for each of the specified (latitude and longitude pair) points.

When this method is run, the weatherZero extension queries the NWS Web service for the weather data of each requested point for the timespan indicated by the startTime and endTime parameters. When the method completes, the global context contains weather information for each point for the entire time span. The information for a given point is located at the following location:

/request/wx/points#<POINT_NUMBER>

Using the valueKeys

ICONS_KEY = "icons"

Strings a URL to an icon depicting overall weather conditions

MAX_DAILY_TEMPS_KEY = "maxDailyTemps"

The integer maximum daily temperature in degrees Fahrenheit

MIN_DAILY_TEMPS_KEY = "minDailyTemps"

The integer minimum daily temperature in degrees Fahrenheit

HOURLY_TEMPS_KEY = "hourlyTemps"

The integer actual temperature in degrees Fahrenheit

APPARENT_TEMPS_KEY = "apparentTemps"

The integer apparent temperature in degrees Fahrenheit

DEWPOINT_TEMPS_KEY = "dewpointTemps"

The integer dewpoint in degrees Fahrenheit

CONDITIONS_KEY = "wxConditions"

The List of Strings describing weather conditions

CLOUD_COVER_KEY = "cloudCover"

The integer percentage of sky covered with clouds

WIND_DIRECTION_KEY = "windDirection"

The direction the wind is coming from in integer degrees (from true north, not magnetic north)

WIND_SPEED_KEY = "windSpeed"

The sustained wind speed (integer knots; mph=knots*1.15)

WIND_GUST_KEY = "windGust"

The wind gust speed (integer knots; mph=knots*1.15)

HUMIDITY_KEY = "humidity"

The relative humidity (integer percentage)

PRECIPITATION_PROBABILITY_KEY = "precipProbability"

The probability of precipitation in a 12 hour period

SNOW_KEY = "snow"

The inches of snow in a 6 hour period

RAIN_KEY = "rain"

The inches of rain in a 6 hour period

Getting results

Navigating all of this through global context URIs would be only slightly more fun than reading regular expressions, so a convenience method is provided. The signature is:

com.tripwx.forecasts.Utils:

public static Object getValueAtTime(String valueKey, int pointIndex, Date time)

Using the parameters

The following parameters are used for this signature:

valueKey

One of the valueKeys listed in the previous example that indicate which type of information to retrieve.

pointIndex

The index into the list of points initially provided to the getWeatherForecast() that resolves to the point for which weather is to be retrieved.

time

The Date object representing the time for which weather forecast information is to be retrieved for the specified point.

Additional resources

• NOAA NWS SOAP weather service