When using a gridded printed map on the field, this quick app tells you the grid square or the location in kilometers on a parcours where you are currently standing.

Demo :

• build grid or parcours : https://grid.my-poppy.eu
• display & locate on grid : https://grid.my-poppy.eu/?0,0,100,45,50,4
• display & locate on grid (new url format) : https://grid.my-poppy.eu/?scr=0&del=100&bea=45&LAT=50&LNG=4&Nx=10&Ny=15&invxy=1&revy=0&bm=mapnik
• display & locate on parcours : https://grid.my-poppy.eu/?lineblob=6b1041ce-68ca-11e8-94d5-3b046b2be916

where

• D7b is the grid square of the map where you are currently standing
• 1.5 km is the kilometric index where you are currently standing

Usage :

• to create the grid / parcours :

  • go to [url]
  • use 'Créer grille : créer', 'Créer parcours' ou 'Importer parcours'
  • draw the grid or the parcours
  • click on 'Partager' to show the url & QR-code

• to know your current location :

  • enable geolocation
  • open the url, eg. [url]?scr,0,bea,del,LAT,LNG,Nx,Ny,invxy,revy

Where

• scr is the reference coordinate system (available options : 31370 : Lambert 72), or 0 for local TMercator
• 0 is currently not used
• del is the grid square length in meters
• bea is the map azimuth in degrees
• LAT,LNG are the WGS84 coordinates of the origin of the local TMercator coordinates system
• Nx is the number of squares in X direction (horizontal)
• Ny is the number of squares in Y direction (vertical)
• invxy : if 0, use letters in x and figures in y. if 1, use figures in x and letters in y
• revy : if 0, y coordinates is from top to bottom, if 0 from bottom to top
• bm : the basemap to use (among the available basemaps)

The graphical user interface only allow to produces a grid in TMercator, with letters in x and figures in y (from top to bottom). But you may tweak the link afterwards.

Full example : https://grid.my-poppy.eu/?31370,0,100,0,50.45019,5.95576,18,27,0,0

To use it operationnally

• the x0, y0,delta,bearing should correspond to your printed map

• x0,y0,delta,bearing,X0,Y0,Nx,Ny are generated by drawing a rectangle using [url]

• you could send the link to your personnel by SMS/Whatsapp/...

• or display it as a QR code

• ideally, they can store the link on their smartphone home screen to use it when they need it

Enjoy !

Credits :

• font-awesome-4.7.0
• Leaflet.EasyButton-1.1.1
• leaflet-1.3.1 (fork from va2ron1 2018-04-06)
• Leaflet.Omnivore-0.3.3
• Proj4Leaflet-0.7.0
• hammer-2.0.8.js
• jquery-2.1.1
• tokml.js
• download2.js

Contact: [email protected]

Presented @ FOSS4G-FR 15-17/5/2018 @ ENSG Paris

in Leaflet, modification of the toGeoJSON function, to also export the names of the elements :

LH.toGeoJSON = function (precision) {
    ...
    this.eachLayer(function (layer) {
        if (layer.toGeoJSON) {
            var json = layer.toGeoJSON(precision);        
            /*THIS SHOULD BE ADDED ->*/ if (layer.options.name != null) if (layer.options.name != '')  json.properties.name =  layer.options.name
             ...

to patch the minified code :

var o=i.toGeoJSON(t);

should be replaced by

var o=i.toGeoJSON(t); if(i.options.name!=null) if(i.options.name!='') o.properties.name=i.options.name;