NOAAForecastKit

Objective-C Wrapper for NOAA's Weather Forecast REST API

Use this project as a starting point for querying weather data from National Digital Forecast Database (NDFD) REST Web Service. FKDataManager is a singleton that queries

• maximum/minimum temperature,
• probability of precipitation,
• and a weather summary

by current location or zipcode. The code can be extended if other data is required.

The project uses zipcode data from CivicSpace Labs, Inc., which is released under a Creative Commons Attribution-ShareAlike license.

ARC and non-ARC supported.

###Add to your project

1. Link CoreData.framework and CoreLocation.framework.
2. Drag the NOAAForecastKit directory into your project.

###Requesting 7-day forecasts

Use the following instance methods of the singleton [FKDataManager sharedManager] to request forecast data.

Request a 7-day forecast at the device's current location:

- (BOOL)requestForecastsForCurrentLocationWithCompletion:(void (^)(NSArray *forecasts, NSError *error))completionHandler
                                                   error:(NSError *__autoreleasing *)preRequestError;

Request a 7-day forecast at a given zipcode:

- (BOOL)requestForecastsForZipcode:(NSString *)zipcode
                        completion:(void (^)(NSArray *forecasts, NSError *error))completionHandler
                             error:(NSError *__autoreleasing *)preRequestError;

If the request cannot be sent, the methods return NO with error details in preRequestError. If the request is sent but fails at any point, forecasts will be nil when completionHandler is called, and error details will be provided in error.

If the request is successful, a NSArray of 7 FKForecast objects is returned. Each FKForecast object has the following properties:

@property (nonatomic, retain) NSNumber * latitude;                    // a float (degrees)
@property (nonatomic, retain) NSNumber * longitude;                   // a float (degrees)
@property (nonatomic, retain) NSDate * startDate;                     // start of forecast period
@property (nonatomic, retain) NSDate * fetchDate;                     // date data was fetched
@property (nonatomic, retain) NSDate * endDate;                       // end of forecast period
@property (nonatomic, retain) NSString * summary;                     // e.g. "Sunny"
@property (nonatomic, retain) NSNumber * minimumTemperature;          // an integer
@property (nonatomic, retain) NSNumber * maximumTemperature;          // an integer
@property (nonatomic, retain) NSString * temperatureUnits;            // Fahrenheit or Celsius
@property (nonatomic, retain) NSNumber * probabilityOfPrecipitation;  // an integer with units of percent

###Get details of a location from a zipcode

[FKDataManager sharedManager] can return details of a zipcode's location, e.g. for populating your UI.

- (FKLocation *)locationForZipcode:(NSString *)zipcode;

This method returns nil if the zipcode passed in is not within the database shipped in the bundle (Zipcodes.sqlite). Otherwise it returns an FKLocation object which has the following properties:

@property (nonatomic, retain) NSNumber * zipcode;
@property (nonatomic, retain) NSString * state;         // two-letter abbreviation
@property (nonatomic, retain) NSNumber * longitude;
@property (nonatomic, retain) NSNumber * latitude;
@property (nonatomic, retain) NSString * city;          // city name

###Customization

To request other data from NDFD, modify the parameters sent to the service in FKForecastRequester, which handles the request to the service and receipt of the response.

- (NSURLRequest *)urlRequestForLatitude:(float)latitude longitude:(float)longitude;

The response is sent to a FKResponseParser, which will also need to be modified. Parsing of the XML response yields a tree of FKSchemaElement objects. Each FKSchemaElement object represents an element (node) in the XML, and has the following properties:

@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) NSString *value;
@property (weak, nonatomic) FKSchemaElement *parent;        // This element's parent in the tree (FKSchemaElement)
@property (nonatomic, readonly) NSMutableArray *children;   // This element's children (FKSchemaElements)
@property (nonatomic, readonly) NSMutableSet *attributes;   // This element's attributes (FKSchemaAttributes)

FKSchemaAttribute instances have:

@property (strong, nonatomic) NSString *name;
@property (strong, nonatomic) NSString *value;

You should customize the creation of FKForecasts in the -createForecasts method and call -reportForecasts when finished.

The structure of the XML responses is specified at http://graphical.weather.gov/xml/mdl/XML/Design/MDL_XML_Design.htm.

Sample responses can be viewed through the following URLs: http://graphical.weather.gov/xml/sample_products/browser_interface/ndfdXML.htm http://graphical.weather.gov/xml/sample_products/browser_interface/ndfdBrowserByDay.htm