From 11c2a1713f407d5fe097f834bbcadf9bb08133fd Mon Sep 17 00:00:00 2001
From: evlist <vdv@dyomedea.com>
Date: Sun, 2 Oct 2022 21:52:02 +0200
Subject: [PATCH] Firstattempt to reduce te number of points when recording a
 track (#13): the minimal distance is now 10m and a filter with a minimal time
 of 15s has been added. This should now be tested on the road !

---
 src/components/map/GpxRecord.tsx  | 54 ++++++++++++++++++++-----------
 src/lib/background-geolocation.ts |  2 +-
 2 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/src/components/map/GpxRecord.tsx b/src/components/map/GpxRecord.tsx
index 704d9c8..9953705 100644
--- a/src/components/map/GpxRecord.tsx
+++ b/src/components/map/GpxRecord.tsx
@@ -1,4 +1,4 @@
-import React, { Fragment, useRef, useState } from 'react';
+import React, { Fragment, useEffect, useRef, useState } from 'react';
 
 import { useDB, useFind } from 'react-pouchdb';
 
@@ -28,6 +28,12 @@ import { enterAnimation, leaveAnimation } from '../../lib/animation';
 import { useDispatch } from 'react-redux';
 import { mapActions } from '../../store/map';
 
+const MIN_TIME_BETWEEN_LOCATIONS = 15 * 1000;
+
+declare global {
+  var $lastValidLocationTime: number;
+}
+
 const GpxRecord: React.FC<{}> = () => {
   const db = useDB();
 
@@ -59,27 +65,39 @@ const GpxRecord: React.FC<{}> = () => {
   const dispatch = useDispatch();
 
   const newLocationHandler = (location: any) => {
-    appendTrkpt(db, {
-      $: {
-        lat: location.latitude,
-        lon: location.longitude,
-      },
-      ele: location.altitude,
-      time: new Date(location.time).toISOString(),
-      extensions: {
-        speed: location.speed,
-        accuracy: location.accuracy,
-      },
-    });
-    dispatch(
-      mapActions.setCurrent({
-        lat: location.latitude,
-        lon: location.longitude,
-      })
+    console.log(
+      `Location filtering, elapsed time: ${
+        location.time - globalThis.$lastValidLocationTime
+      }`
     );
+    if (
+      location.time - globalThis.$lastValidLocationTime >
+      MIN_TIME_BETWEEN_LOCATIONS
+    ) {
+      globalThis.$lastValidLocationTime = location.time;
+      appendTrkpt(db, {
+        $: {
+          lat: location.latitude,
+          lon: location.longitude,
+        },
+        ele: location.altitude,
+        time: new Date(location.time).toISOString(),
+        extensions: {
+          speed: location.speed,
+          accuracy: location.accuracy,
+        },
+      });
+      dispatch(
+        mapActions.setCurrent({
+          lat: location.latitude,
+          lon: location.longitude,
+        })
+      );
+    }
   };
 
   const startRecording = () => {
+    globalThis.$lastValidLocationTime = 0;
     startBackgroundGeolocation(newLocationHandler).then((result) => {
       setWatcher_id(result);
     });
diff --git a/src/lib/background-geolocation.ts b/src/lib/background-geolocation.ts
index 795bda4..052ccb5 100644
--- a/src/lib/background-geolocation.ts
+++ b/src/lib/background-geolocation.ts
@@ -31,7 +31,7 @@ const backgroundGeolocationConfig = {
 
   // The minimum number of metres between subsequent locations. Defaults
   // to 0.
-  distanceFilter: 5,
+  distanceFilter: 10,
 };
 
 export const startBackgroundGeolocation = async (newLocationHandler: any) => {