Water Components

High-level technical requirements

• Take full advantage of Automatic Reference Counting

• Use blocks for NSURLConnection success/failure handling

• Use blocks when making calls to classes that report success/failure

• Retrieve gauges for agencies:

  • USGS
  • USACE

• Retrieve most recent height level reading

• Retrieve precipitation totals, if available for:

  • Past 24 hours
  • Past 7 days
  • Since date?

• Map USGS gage ID to NWS gage ID

• Retrieve flood stage levels from NWS for a given gauge

• Retrieve discharge levels for USGS gauge for:

  • Past 24 hours
  • Past 7 days
  • Since date?

• Render graph of readings with arbitrary X and Y axes

Class and interface structure

• DFGWaterGaugeDataRequestParameters

  • gaugeID -- NSString
  • height -- BOOL
  • precipitation -- BOOL
  • discharge -- BOOL
  • delegate -- id
  • Date values -- only get most recent value if all of these are null
    • sinceDate
    • endDate
    • numDaysAgo
  • initWithGaugeID:numDaysAgo:height:precipitation:discharge:
  • initWithGaugeID:sinceDate:endDate:height:precipitation:discharge:
  • initWithGaugeIDForMostRecentReading:height:precipitation:discharge:
  • initWithGaugeIDForAllMostRecentReadings:
    • calls to method above with all BOOLs set to YES

• DFGWaterGaugeDataRetrieverProtocol

  • Methods:
    • retrieveData:(DFGWaterGaugeDataRequestParameters*)params
  • Implementations:
    • USGS: DFGWaterUSGSGaugeDataRetriever
    • USACE: DFGWaterUSGSGaugeDataRetriever

• DFGWaterGaugeDataRetrieverDelegateProtocol

  • retriever:willRetrieveDataForParameters:
  • retriever:didFailToRetrieveDataForParameters:
  • retriever:retrievedHeightReadings:forParameters:
  • retriever:retrievedPrecipitationReadings:forParameters:
  • retriever:retrievedDischargeReadings:forParameters:
  • retriever:didFailToRetrieveHeightReadingsForParameters:error:
  • retriever:didFailToRetrievePrecipitationReadingsForParameters:error:
  • retriever:didFailToRetrieveDischargeReadingsForParameters:error:
  • retriever:heightReadingsNotAvailableForParameters:
  • retriever:precipitationReadingsNotAvailableForParameters:
  • retriever:dischargeReadingsNotAvailableForParameters:

• DFGWaterReading

  • initWithValue:(NSString*)value
  • initWithValue:atDate:
  • value -- NSString
  • date -- NSDate

Use cases

1. What's the current height at gauge XXXXX?
   • Create params object: initWithGaugeIDForMostRecentReading:@"02336910" height:YES precipitation:NO discharge:NO
   • Use retriever: retrieveData:params
   • Get delegate message: retriever:retrievedHeightReadings:forParameters:
2. Give me all data available for gauge XXXXX
   • Create params object: initWithGaugeIDForMostRecentReading:@"02336910" height:YES precipitation:YES discharge:YES
   • Use retriever: retrieveData:params
   • Get delegate message: retriever:retrievedHeightReadings:forParameters:
   • Get delegate message: retriever:retrievedPrecipitationReadings:forParameters:
   • Get delegate message: retriever:retrievedDischargeReadings:forParameters: