BaNazari
commented
4 years ago a. we don't need to set endDate as Date.now(). What if the user has gone out only once 5 days ago? It's better to end the time range to the last date and time of the user's footprint. It keeps the query smaller. b. I don't think that the idea of "radius" works here. Suppose the user has gone to buy milk in the shop A and it is 10x10 meters. Shop B is side by side with A but separated. At least we can check for the Google map's default value for radius not being too big.
marleymarl
heldersepu
The purpose of this component is to provide a way for people who don't have coronavirus to:
a. view the local data of footprint histories (within time ranges) on a map b. enter in their own footprint histories (which don't save to a db) and have it automatically check (after they hit 'check for matches') if they have come into contact with confirmed cases, and highlight any geotimeline footprint matches (i.e. were in proximity with each other based on datetime window and distance proximity).
The first step is to create the component and display some footprints on a map based on a date range of last 14 days and some radius (whatever the default google maps view provides) around the centerLat and centerLon of the map.
The function to push footprints into the footPrintMarkerViewArray based on radius should be something like:
function distance(lat1, lon2, lat2, long2) { var R = radiusDistance // (whatever the distance is of default map radius) return Math.acos(Math.sin(lat1)*Math.sin(lat2) + Math.cos(lat1)*Math.cos(lat2) * Math.cos(lon2-lon1)) * R; }if (distance(centerLat, centerLon, footprint.lat, footprint.lon) <= desiredRadiusInKm) { //i.e. desiredRadiusInKim = radiusDistance push the footprint into the array of markers to display on map i.e. footPrintMarkerViewArray } else { don't }Source: https://stackoverflow.com/questions/22108307/filter-to-only-show-data-within-the-radius-of-a-point-using-longitude-and-latitu/22112456To get initial footPrints within a date range, do something like:
a. calculate starting date of 14 days ago as startDate using moment lib and endDate using Date.now() b. reformat each footprints date and time as a timestamp c. filter resulting footPrintMarkerViewArray (result of previous function) and push footprints into new footPrintMarkerViewArrayFinal whose timestamps fall between startDate and endDate.
Eventually a date range query will be available from backend API (and ditto for distance proximity) https://github.com/marleymarl/geotimeline-backend/issues/1 but the above gets the component up and running without waiting for that.