Merge pull request #23 from oyve/v2.1.5

v2.2.0

README.md

@@ -1,16 +1,20 @@
 ![Node.js CI](https://github.com/oyve/barometer-trend/workflows/Node.js%20CI/badge.svg)
 # barometer-trend
-Calculate the trend of a barometer over a three hour period.
+Calculate the tendency and trend of a barometer for a one to three hour period with barometric weather predictions.
 
 ## Features
-Gets the suggested:
-- Tendency and trend of the barometer for the *last hour* or *three hours* (`FALLNG|SLOWLY`)
-- Front system tendency, passage and wind analyze based on the latest three hours. (`Falling before a lesser rise` | `Cold front passage` | `Strong and gusty, then veers`)
-- Force wind expectation in Beaufort scale based on the ratio of pressure increase/decrease (`F8-9`)
-- Prediction of weather by ratio of increase/decrease trend (`Expect gale force weather'`)
-- Prediction of weather by pressure tendency, threshold and wind direction (`Increasing rain, clearing within 12 hours.`)
-- Prediction of weather by pressure threshold for winter|summer (`Cloudy and humid, thunderstorms`)
+- Tendency and trend of the barometer for the *last hour* or *three hours* (`FALLNG|SLOWLY`)- 
+- Prediction of weather and systems:
+  - By pressure tendency only (`Expect gale force weather'`)
+  - By pressure tendency, thresholds and wind direction (`Increasing rain, clearing within 12 hours.`)
+  - By seasonal pressure thresholds for winter and summer (`Cloudy and humid, thunderstorms`)
+  - Front system tendency for the last three hours (`Falling before a lesser rise` | `Cold front passage` | `Strong and gusty, then veers`)
+  - Force wind expectation in Beaufort scale based on the pressure tendency (`F8-9`)
+- Detects current pressure system `Low`, `Normal`, `High`
+
+Note
 - All calculations corrected to sea level pressure by optional `altitude` and `temperature`
+- 48 hour history
 
 ## Install & Use
 ```
@@ -22,27 +26,28 @@ const barometer = require('barometer-trend');
 
 barometer.addPressure(datetime1, 101500);
 barometer.addPressure(datetime2, 101505);
-barometer.addPressure(datetime3, 101512, 100, 20, 225); //100 = altitude, 20 = C degrees, 225 = wind direction - enables more calculations (or give NULL for each seperately)
+barometer.addPressure(datetime3, 101512, 100, 20, 225); //100 = altitude, 20 = C degrees, 225 = wind direction 
 
-let forecast = barometer.getPredictions();
+//barometer.addPressure(...) is more presice when pressure is corrected by altitude and temperature.
+
+let forecast = barometer.getPredictions(); //returns JSON
 ```
 
 ## Note
-- Pressure must be in Pascals, 1015 mBar/hPa = 101500 Pascal.
-- Pressure readings older than *three hours* are automatically removed.
+- Pressure must be input in Pascals, 1015 mBar/hPa = 101500 Pascal.
 - `getPredictions()` investigate the trend for the latest *one hour* and *three hours*
 - If run less than *one hour* or *three hours*, the latest timing up until now is picked.
-- The most recent trend with the highest severity is chosen.
+- The most recent trend with the highest severity is chosen (*One hour* or *Three hour* reading)
 
 ## Contribute
-Feel free to create a Pull Request including test code.
+Feel free to contribute; create an Issue, and Pull Request including test code.
 
 ## Disclaimer
 - All calculations is done by online research; the author of this library does not have a background in metereology. All sources listed below.
 - A barometer is only *one source of weather information* and may give a general trend and indication, but not "see" the overall picture. (There's a reason satelittes exists and being a metereologist is a paid job.)
 - All calculations presumes being located at sea with no disturbances.
 - Near land, winds may be one-two Beaufort scale numbers lower and the wind might be coming from "the wrong direction".
-- In subtropic and tropical regions some of the calculations may not be valid at all; i.e. the tradewind system is different from northern hemishpere west->east low pressure systems.
+- In subtropic and tropical regions some of the calculations may not be valid at all; i.e. the trade winds (easterlies) is different from northern hemishpere west->east (westerlies) low pressure systems.
 - In trade wind zones observe the daily variations; any change to this pattern could possibly indicate gale weather.
 
 ## Sources / References

index.js

@@ -6,6 +6,8 @@ const byPressureTrendAndSeason = require('./predictions/byPressureTrendAndSeason
 const beaufort = require('./predictions/beaufort')
 const trend = require('./trend');
 const utils = require('./utils');
+const history = require('./predictions/history');
+const system = require('./predictions/system');
 
 let pressures = [];
 
@@ -29,24 +31,26 @@ function hasPressures() {
  * @param {number} trueWindDirection True wind direction in degrees
  */
 function addPressure(datetime, pressure, altitude = null, temperature = null, trueWindDirection = null) {
-    if (trueWindDirection !== null && trueWindDirection === 360) trueWindDirection = 0;
     if (altitude === null) altitude = 0;
-    if (temperature === null) temperature = 15 + utils.KELVIN;
+    if (temperature === null) temperature = utils.toKelvinFromCelcius(15);
+    if (trueWindDirection !== null && trueWindDirection === 360) trueWindDirection = 0;
 
-    if (altitude > 0) {
-        pressure = utils.adjustPressureToSeaLevel(pressure, altitude, temperature);
-    }
+    let pressureASL = utils.adjustPressureToSeaLevel(pressure, altitude, temperature);
 
     pressures.push({
         datetime: datetime,
-        value: pressure,
-        twd: trueWindDirection
+        value: pressureASL,
+        meta: {
+            value: pressure,
+            altitude: altitude,
+            temperature: temperature,
+            twd: trueWindDirection
+        }
     });
 
     removeOldPressures();
 }
 
-
 /**
  * Get the count of pressure entries. (Mainly for testing purposes)
  * @returns {number} Number of pressure entries
@@ -55,15 +59,20 @@ function getPressureCount() {
     return pressures.length;
 }
 
-function removeOldPressures(threshold) {
-    var threshold = utils.minutesFromNow(-utils.MINUTES.THREE_HOURS);
+function removeOldPressures(threshold = null) {
+    if (threshold === null) {
+        threshold = utils.minutesFromNow(-utils.MINUTES.FORTYEIGHT_HOURS);
+    }
+
     pressures = pressures.filter((p) => p.datetime.getTime() >= threshold.getTime());
 }
 
 function getLastPressure() {
     return pressures[pressures.length - 1];
 }
 
+
+
 /**
  * Get the trend of the barometer
  * @param {boolean} isNorthernHemisphere Located north of equator? Default true.
@@ -74,16 +83,20 @@ function getPredictions(isNorthernHemisphere = true) {
 
     let lastPressure = getLastPressure();
 
-    var pressureTrend = trend.getTrend(pressures);
+    let pressureTrend = trend.getTrend(pressures);
+    let pressureSystem = system.getSystemByPressure(lastPressure.value);
+    let pressureHistory = history.getHistoricPressures(pressures);
     let predictionPressureOnly = byPressureTrend.getPrediction(pressureTrend.tendency, pressureTrend.trend);
     let predictionFront = front.getFront(pressures);
     let predictionBeaufort = beaufort.getByPressureVariationRatio(pressureTrend.ratio);
     let predictionSeason = byPressureTrendAndSeason.getPrediction(lastPressure.value, pressureTrend.tendency, pressureTrend.trend, utils.isSummer(isNorthernHemisphere))
-    let predictionPressureTendencyThresholdAndQuadrant = byPressureTendencyAndWind.getPrediction(lastPressure.value, lastPressure.twd, pressureTrend.tendency, pressureTrend.trend, isNorthernHemisphere);
+    let predictionPressureTendencyThresholdAndQuadrant = byPressureTendencyAndWind.getPrediction(lastPressure.value, lastPressure.meta.twd, pressureTrend.tendency, pressureTrend.trend, isNorthernHemisphere);
 
     let forecast = {
+        lastPressure: lastPressure,
+        history: pressureHistory,
         trend: pressureTrend,
-        indicator: "Please update JSON, see latest documentation",
+        system: pressureSystem,
         predictions: {
             pressureOnly: predictionPressureOnly,
             quadrant: predictionPressureTendencyThresholdAndQuadrant,