get outlook data

cors/outlook.js

@@ -0,0 +1,45 @@
+// pass through api requests
+
+// http(s) modules
+const https = require('https');
+
+// url parsing
+const queryString = require('querystring');
+
+// return an express router
+module.exports = (req, res) => {
+	// add out-going headers
+	const headers = {};
+	headers['user-agent'] = '(WeatherStar 4000+, ws4000@netbymatt.com)';
+	headers['accept'] = req.headers.accept;
+
+	// get query paramaters if the exist
+	const queryParams = Object.keys(req.query).reduce((acc, key) => {
+		// skip the paramater 'u'
+		if (key === 'u') return acc;
+		// add the paramter to the resulting object
+		acc[key] = req.query[key];
+		return acc;
+	},{});
+	let query = queryString.encode(queryParams);
+	if (query.length > 0) query = '?' + query;
+
+	// get the page
+	https.get('https://www.cpc.ncep.noaa.gov/' + req.path + query, {
+		headers,
+	}, getRes => {
+		// pull some info
+		const {statusCode} = getRes;
+		// pass the status code through
+		res.status(statusCode);
+
+		// set headers
+		res.header('content-type', getRes.headers['content-type']);
+		res.header('last-modified', getRes.headers['last-modified']);
+		// pipe to response
+		getRes.pipe(res);
+
+	}).on('error', e=>{
+		console.error(e);
+	});
+};

index.js

@@ -10,10 +10,12 @@ app.set('view engine', 'ejs');
 // cors pass through
 const corsPassThru = require('./cors');
 const radarPassThru = require('./cors/radar');
+const outlookPassThru = require('./cors/outlook');
 
 // cors pass-thru to api.weather.gov
 app.get('/stations/*', corsPassThru);
 app.get('/Conus/*', radarPassThru);
+app.get('/products/*', outlookPassThru);
 
 // version
 const version = require('./version');

server/scripts/modules/almanac.js

@@ -26,11 +26,10 @@ class Almanac extends WeatherDisplay {
 
 		// get images for outlook
 		const imagePromises = [
-			utils.image.load('https://www.cpc.ncep.noaa.gov/products/predictions/30day/off14_temp.gif'),
-			utils.image.load('https://www.cpc.ncep.noaa.gov/products/predictions/30day/off14_prcp.gif'),
+			utils.image.load('products/predictions/30day/off14_temp.gif'),
+			utils.image.load('products/predictions/30day/off14_prcp.gif'),
 		];
 
-
 		// get sun/moon data
 		const {sun, moon} = this.calcSunMoonData(weatherParameters);
 
@@ -38,7 +37,7 @@ class Almanac extends WeatherDisplay {
 		const [outlookTemp, outlookPrecip] = await Promise.all(imagePromises);
 
 		console.log(outlookTemp,outlookPrecip);
-		const outlook = 1;
+		const outlook = this.parseOutlooks(weatherParameters.latitude, weatherParameters.longitude, outlookTemp, outlookPrecip);
 
 		// store the data
 		this.data =  {
@@ -125,6 +124,114 @@ class Almanac extends WeatherDisplay {
 		return {phase: phaseName, date: moonDate};
 	}
 
+	// use the color of the pixel to determine the outlook
+	parseOutlooks(lat, lon, temp, precip) {
+		const {DateTime} = luxon;
+		const month = DateTime.local().toLocaleString({month: 'long'});
+
+		// draw the images on the canvases
+		const tempContext = utils.image.drawLocalCanvas(temp);
+		const precipContext = utils.image.drawLocalCanvas(precip);
+
+		// get the color from each canvas
+		const tempColor = this.getOutlookColor(lat, lon, tempContext);
+		const precipColor = this.getOutlookColor(lat, lon, precipContext);
+
+		return {
+			month,
+			temperature: this.getOutlookTemperatureIndicator(tempColor),
+			precipitation: this.getOutlookPrecipitationIndicator(precipColor),
+		};
+	}
+
+	getOutlookColor (lat, lon, context) {
+		let x = 0;
+		let y = 0;
+
+		// The height is in the range of latitude 75'N (top) - 15'N (bottom)
+		y = ((75 - lat) / 53) * 707;
+
+		if (lat < 48.83) {
+			y -= Math.abs(48.83 - lat) * 2.9;
+		}
+		if (lon < -100.46) {
+			y -= Math.abs(-100.46 - lon) * 1.7;
+		} else {
+			y -= Math.abs(-100.46 - lon) * 1.7;
+		}
+
+		// The width is in the range of the longitude ???
+		x = ((-155 - lon) / -110) * 719; // -155 - -40
+
+		if (lon < -100.46) {
+			x -= Math.abs(-100.46 - lon) * 1;
+
+			if (lat > 40) {
+				x += Math.abs(40 - lat) * 4;
+			} else {
+				x -= Math.abs(40 - lat) * 4;
+			}
+		} else {
+			x += Math.abs(-100.46 - lon) * 2;
+
+			if (lat < 36 && lon > -90) {
+				x += Math.abs(36 - lat) * 8;
+			} else {
+				x -= Math.abs(36 - lat) * 6;
+			}
+		}
+
+		// The further left and right from lat 45 and lon -97 the y increases
+		x = Math.round(x);
+		y = Math.round(y);
+
+		// Determine if there is any "non-white" colors around the area.
+		// Search a 16x16 region.
+		for (let colorX = x - 8; colorX <= x + 8; colorX++) {
+			for (let colorY = y - 8; colorY <= y + 8; colorY++) {
+				const pixelColor = this.getPixelColor(context, colorX, colorY);
+				if ((pixelColor.r !== 0 && pixelColor.g !== 0 && pixelColor.b !== 0) ||
+					(pixelColor.r !== 255 && pixelColor.g !== 255 && pixelColor.b !== 255)) {
+					return pixelColor;
+				}
+			}
+		}
+
+		return false;
+	}
+
+	// get rgb values of a pixel
+	getPixelColor (context, x, y) {
+		const pixelData = context.getImageData(x, y, 1, 1).data;
+		return {
+			r: pixelData[0],
+			g: pixelData[1],
+			b: pixelData[2],
+		};
+	}
+
+	// get temperature outlook from color
+	getOutlookTemperatureIndicator(pixelColor) {
+		if (pixelColor.b > pixelColor.r) {
+			return 'B';
+		} else if (pixelColor.r > pixelColor.b) {
+			return 'A';
+		} else {
+			return 'N';
+		}
+	}
+
+	// get precipitation outlook from color
+	getOutlookPrecipitationIndicator (pixelColor) {
+		if (pixelColor.g > pixelColor.r) {
+			return 'A';
+		} else if (pixelColor.r > pixelColor.g) {
+			return 'B';
+		} else {
+			return 'N';
+		}
+	}
+
 	async drawCanvas() {
 		super.drawCanvas();
 		const info = this.data;

server/scripts/modules/utilities.js

@@ -58,6 +58,22 @@ const utils = (() => {
 		return true;
 	};
 
+	// draw an image on a local canvas and return the context
+	const drawLocalCanvas = (img) => {
+		// create a canvas
+		const canvas = document.createElement('canvas');
+		canvas.width = img.width;
+		canvas.height = img.height;
+
+		// get the context
+		const context = canvas.getContext('2d');
+		context.imageSmoothingEnabled = false;
+
+		// draw the image
+		context.drawImage(img, 0,0);
+		return context;
+	};
+
 	// *********************************** unit conversions ***********************
 
 	Math.round2 = (value, decimals) => Number(Math.round(value + 'e' + decimals) + 'e-' + decimals);
@@ -374,6 +390,7 @@ const utils = (() => {
 			load: loadImg,
 			superGifAsync,
 			preload,
+			drawLocalCanvas,
 		},
 		weather: {
 			getPoint,