Polygon Drawing and Getting Coordinates with Google Map API v3

Question

I m trying to develop an application by using Google Maps API v3  What I m trying to do is  first let the user draw a polygon on a Google Map and get his her polygon s coordinates and save them into a database  I will then show the user saved coordinates   I don t know how to let users draw polygon on a Google Map with API v3 and then get the coordinates  If I can get those coordinates  it s easy to save them into a database   http   gmaps-samples googlecode com svn trunk poly mymapstoolbar html is nearly the exact example but it uses API v2 and doesn t give coordinates  I want to use API v3 and be able to get all coordinates   Is there any examples of drawing polygon and getting its coordinates with API v3

User · Answer

It s cleaner safer to use the getters provided by google instead of accessing the properties like some did  google maps event addListener drawingManager   overlaycomplete   function polygon        var coordinatesArray   polygon overlay getPath   getArray

User · Answer

Since Google updates sometimes the name of fixed object properties  the best practice is to use GMaps V3 methods to get coordinates event overlay getPath   getArray   and to get lat latlng lat   and lng latlng lng      So  I just wanted to improve this answer a bit exemplifying with polygon and POSTGIS insert case scenario   google maps event addListener drawingManager   overlaycomplete   function event        var str input   POLYGON         if  event type    google maps drawing OverlayType POLYGON          console log  polygon path array   event overlay getPath   getArray             each event overlay getPath   getArray    function key  latlng           var lat   latlng lat            var lon   latlng lng            console log lat  lon            str input    lat       lon                           str input   str input substr 0 str input length-1              console log  the str input will be    str input           YOU CAN THEN USE THE str inputs AS IN THIS EXAMPLE OF POSTGIS POLYGON INSERT        INSERT INTO your table  the geom  name  VALUES  ST GeomFromText str input  4326    Test

User · Answer

Adding to Gisheri s answer   Following code worked for me    var drawingManager   new google maps drawing DrawingManager       drawingMode  google maps drawing OverlayType MARKER      drawingControl  true      drawingControlOptions          position  google maps ControlPosition TOP CENTER        drawingModes            google maps drawing OverlayType POLYGON                    markerOptions          icon   images beachflag png             circleOptions          fillColor    ffff00         fillOpacity  1        strokeWeight  5        clickable  false        editable  true        zIndex  1                 google maps event addListener drawingManager   overlaycomplete   function polygon            console log polygon overlay latLngs j 0  j  return false            each polygon overlay latLngs j 0  j  function key  LatLongsObject               var LatLongs        LatLongsObject               var lat   LatLongs k              var lon   LatLongs B             console log  Lat is    lat   Long is    lon     do something with the coordinates

User · Answer

to accomplish what you want  you must getPaths from the polygon   Paths will be an array of LatLng points   you get the elements of the array and split the LatLng pairs with the methods  lat and  lng  in the function below  i have a redundant array corresponding to a polyline that marks the perimeter around the polygon   saving is another story   you can then opt for many methods   you may save your list of points as a csv formatted string and export that to a file  easiest solution  by far    i highly recommend GPS TXT formats  like the ones  there are 2  readable by GPS TRACKMAKER  great free version software     if you are competent to save them to a database  that is a great solution  i do both  for redundancy      function areaPerimeterParse areaPerimeterPath        var flag1stLoop   true      var areaPerimeterPathArray   areaPerimeterPath getPath        var markerListParsedTXT    Datum WGS84 WGS84 0 0 0 0 0 r n        var counter01   0      var jSpy           for  var j   0 j lt areaPerimeterPathArray length j              counter01            jSpy    j               if  flag1stLoop                markerListParsedTXT     TP D     areaPerimeterPathArray getAt j  lat    areaPerimeterPathArray getAt j  lng    join        00 00 00 00 00 00 1    r n               flag1stLoop   false            else               markerListParsedTXT     TP D     areaPerimeterPathArray getAt j  lat    areaPerimeterPathArray getAt j  lng    join        00 00 00 00 00 00 0    r n                           last point repeats first point     markerListParsedTXT     TP D     areaPerimeterPathArray getAt 0  lat    areaPerimeterPathArray getAt 0  lng    join        00 00 00 00 00 00 0    r n       return markerListParsedTXT      attention  the line that ends with   1   as opposed to   0   starts a new polygon  this format allows you to save multiple polygons in the same file    i find TXT more human readable than the XML based formats GPX and KML

User · Answer

If all you need is the coordinates here is a drawing tool I like to use - move the polygon or re-shape it and the coordinates will display right below the map  jsFiddle here   Also  here is a Codepen  JS  var bermudaTriangle  function initialize         var myLatLng   new google maps LatLng 33 5190755  -111 9253654       var mapOptions             zoom  12          center  myLatLng          mapTypeId  google maps MapTypeId RoadMap             var map   new google maps Map document getElementById  map-canvas                                      mapOptions         var triangleCoords             new google maps LatLng 33 5362475  -111 9267386           new google maps LatLng 33 5104882  -111 9627875           new google maps LatLng 33 5004686  -111 9027061                  Construct the polygon     bermudaTriangle   new google maps Polygon           paths  triangleCoords          draggable  true          editable  true          strokeColor    FF0000           strokeOpacity  0 8          strokeWeight  2          fillColor    FF0000           fillOpacity  0 35              bermudaTriangle setMap map       google maps event addListener bermudaTriangle   dragend   getPolygonCoords       google maps event addListener bermudaTriangle getPath     insert at   getPolygonCoords       google maps event addListener bermudaTriangle getPath     remove at   getPolygonCoords       google maps event addListener bermudaTriangle getPath     set at   getPolygonCoords      function getPolygonCoords         var len   bermudaTriangle getPath   getLength        var htmlStr           for  var i   0  i  lt  len  i              htmlStr    bermudaTriangle getPath   getAt i  toUrlValue 5      lt br gt              document getElementById  info   innerHTML   htmlStr      HTML   lt body onload  initialize    gt       lt h3 gt Drag or re-shape for coordinates to display below lt  h3 gt       lt div id  map-canvas  gt       lt  div gt       lt div id  info  gt       lt  div gt   lt  body gt    CSS   map-canvas       width  auto      height  350px     info       position  absolute      font-family  arial  sans-serif      font-size  18px      font-weight  bold

User · Answer

Cleaned up what chuycepeda has and put it into a textarea to send back in a form   google maps event addListener drawingManager   overlaycomplete   function  event        var str input            if  event type    google maps drawing OverlayType POLYGON              each event overlay getPath   getArray    function  key  latlng                var lat   latlng lat                var lon   latlng lng                str input    lat          lon                              str input   str input substr 0  str input length - 1                 textarea Geofence   val str input

User · Answer

here you have the example above using API V3  http   nettique free fr gmap toolbar html

User · Answer

Well  unfortunately it seems that one cannot place custom markers and draw  and obtain coordinates  directly from maps google com if one is anonymous not logged in  as it was possible some years ago  if I recall correctly   Still  thanks to the answers here  I managed to make a combination of examples that has both the Google Places search  and allows drawing via the drawing library  and dumps coordinates upon making a selection of any type of shape  including coordinates for polygon  that can be copypasted  the code is here    https   gist github com anonymous 68b8f6a586c512cfc768 file-gmaps-drawing-tools-places-htm   This is how it looks like      The Places markers are handled separately  and can be deleted via the DEL  button  by the search input form element   curpos  shows the current center  position  and zoom level of the map viewport

User · Answer

try this   In your controller use    gt   scope onMapOverlayCompleted   onMapOverlayCompleted   gt    gt   function onMapOverlayCompleted e     gt    gt                  e overlay getPath   getArray   forEach function  position     gt                      console log  lat   position lat      gt                      console log  lng   position lng      gt                       gt    gt        In Your html page   include drawning manaer           lt ng-map id  geofence-map  zoom  8  center  current  default-style  true  class  map-layout map-area                          tilt  45                          heading  90  gt                        lt drawing-manager                             on-overlaycomplete  onMapOverlayCompleted                                drawing-control-options   position   TOP CENTER  drawingModes   polygon   circle                                 drawingControl  true                              drawingMode  null                              markerOptions   icon  www example com icon                                rectangleOptions   fillColor   B43115                                circleOptions   fillColor    F05635  fillOpacity  0 50 strokeWeight  5 clickable  false zIndex  1 editable  true   gt                       lt  drawing-manager gt       lt  ng-map gt

User · Answer

The other answers show you to create the polygons  but not how to get the coordinates     I m not sure the best way to do it  but heres one way   It seems like there should be a method to get the paths from the polygon  but I can t find one  and getPath   doesn t seem to work for me  So here s a manual approach that worked for me    Once you ve finished drawing your polygon  and pass in your polygon to the overlay complete function  you can find the coordinates in the polygon overlay latLngs b 0  b  google maps event addListener drawingManager   overlaycomplete   function polygon              each polygon overlay latLngs b 0  b  function key  latlng               var lat   latlng d              var lon   latlng e              console log lat  lon     do something with the coordinates                   note  i m using jquery to loop over the list of coordinates  but you can do loop however

[google-maps] Polygon Drawing and Getting Coordinates with Google Map API v3

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