Update Documentation & Fix location handling

Adding example environment variable config.

Signed-off-by: Gnanakeethan Balasubramaniam <[email protected]>

docs/implementations/watt-time.md

@@ -10,8 +10,7 @@ WattTime technology—based on real-time grid data, cutting-edge algorithms, and
 WattTime Model provides a way to calculate emissions for a given time in a specific location. 
 
 The model is based on the WattTime API. The model uses the following inputs:
-* latitude: Location of the software system (latitude in decimal degrees).
-* longitude: Location of the software system (longitude in decimal degrees).
+* location: Location of the software system (latitude in decimal degrees, longitude in decimal degrees). "latitude,longitude"
 * timestamp: Timestamp of the recorded event (2021-01-01T00:00:00Z) RFC3339
 * duration: Duration of the recorded event in seconds (3600)
 
@@ -26,13 +25,27 @@ Limitations:
 
 
 WattTime API requires activation of subscription before usage. Please refer to WattTime website for more information.
+https://www.watttime.org/get-the-data/data-plans/
 
 **Required Parameters:**
-
+```
+# example environment variable config , prefix the environment variables with "ENV" to load them inside the model.
+# export WATT_TIME_USERNAME=test1
+# export WATT_TIME_PASSWORD=test2
+```
 * username: Username for the WattTime API
+  * ENV_WATT_TIME_USERNAME - specifying this value enables the RIMPL to load the value from the environment variable
 * password: Password for the WattTime API
+  * ENV_WATT_TIME_PASSWORD - specifying this value enables the RIMPL to load the value from the environment variable
 
 
+### Observations 
+
+**Required Parameters:**
+* timestamp: Timestamp of the recorded event (2021-01-01T00:00:00Z) RFC3339
+* location: Location of the software system (latitude in decimal degrees, longitude in decimal degrees). "latitude,longitude"
+* duration: Duration of the recorded event in seconds (3600)
+
 ### Typescript Usage
 ```typescript
 // environment variable configuration
@@ -46,8 +59,7 @@ const env_model = await new WattTimeGridEmissions().configure('watt-time', {
 const observations = [
   {
     timestamp: '2021-01-01T00:00:00Z',
-    latitude: 43.22,
-    longitude: -80.22,
+    latitude: "43.22,-80.22",
     duration: 3600,
   },
 ];
@@ -65,8 +77,7 @@ config:
   password: ENV_WATT_TIME_PASSWORD
 observations:
   - timestamp: 2021-01-01T00:00:00Z
-    latitude: 43.22
-    longitude: -80.22
+    latitude: "43.22,-80.22"
     duration: 3600
 ```
 #### Static configuration for IMPL
@@ -76,7 +87,6 @@ config:
   password: password
 observations:
   - timestamp: 2021-01-01T00:00:00Z
-    latitude: 43.22
-    longitude: -80.22
+    latitude: "43.22,-80.22"
     duration: 3600
 ```

src/lib/watt-time/index.ts

@@ -136,8 +136,12 @@ export class WattTimeGridEmissions implements IImpactModelInterface {
 
   private validateObservations(observations: object[]) {
     observations.forEach((observation: KeyValuePair) => {
-      if (!('latitude' in observation) || !('longitude' in observation)) {
-        throw new Error('latitude or longitude is missing');
+      if (!('location' in observation)) {
+        const {latitude, longitude} =
+          this.getLatitudeLongitudeFromObservation(observation);
+        if (isNaN(latitude) || isNaN(longitude)) {
+          throw new Error('latitude or longitude is not a number');
+        }
       }
       if (!('timestamp' in observation)) {
         throw new Error('timestamp is missing');
@@ -148,6 +152,24 @@ export class WattTimeGridEmissions implements IImpactModelInterface {
     });
   }
 
+  private getLatitudeLongitudeFromObservation(observation: KeyValuePair) {
+    const location = observation['location'].split(','); //split location into latitude and longitude
+    if (location.length !== 2) {
+      throw new Error(
+        'location should be a comma separated string of latitude and longitude'
+      );
+    }
+    if (location[0] === '' || location[1] === '') {
+      throw new Error('latitude or longitude is missing');
+    }
+    if (location[0] === '0' || location[1] === '0') {
+      throw new Error('latitude or longitude is missing');
+    }
+    const latitude = parseFloat(location[0]); //convert latitude to float
+    const longitude = parseFloat(location[1]); //convert longitude to float
+    return {latitude, longitude};
+  }
+
   private determineObservationStartEnd(observations: object[]) {
     // largest possible start time
     let starttime = dayjs('9999-12-31');
@@ -185,10 +207,12 @@ export class WattTimeGridEmissions implements IImpactModelInterface {
     if (duration > 32 * 24 * 60 * 60) {
       throw new Error('duration is too long');
     }
+    const {latitude, longitude} =
+      this.getLatitudeLongitudeFromObservation(observation);
 
     const params = {
-      latitude: observation.latitude,
-      longitude: observation.longitude,
+      latitude: latitude,
+      longitude: longitude,
       starttime: dayjs(observation.timestamp).format('YYYY-MM-DDTHH:mm:ssZ'),
       endtime: dayjs(observation.timestamp).add(duration, 'seconds'),
     };