How to save a Google maps overlay shape in the database?
I want to save a Google maps overlay shape in the database. This is my code. It works perfectly but I just need to save all_shapes array in the database.
<html>
<head>
<style type="text/css">
#map, html, body
{
padding: 0;
margin: 0;
height: 100%;
}
</style>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=true&libraries=drawing,geometry"></script>
<script>
var coordinates = [];
var all_shapes = [];
var selectedShape;
</script>
<script>
function draw_shape()
{
for(var i = 0; i < all_shapes.length; i++)
{
all_shapes[i].setMap(null);
}
for(var i = 0; i < all_shapes.length; i++)
{
all_shapes[i].setMap(map);
}
}
</script>
<script>
function clearSelection()
{
if(selectedShape)
{
selectedShape.setEditable(false);
selectedShape = null;
}
}
function setSelection(shape)
{
clearSelection();
selectedShape = shape;
shape.setEditable(true);
}
function deleteSelectedShape()
{
if (selectedShape)
{
selectedShape.setMap(null);
}
}
</script>
<script>
function save_coordinates_to_array(newShapeArg)
{
if(newShapeArg.type == google.maps.drawing.OverlayType.POLYGON)
{
var polygonBounds = newShapeArg.getPath();
for(var i = 0 ; i < polygonBounds.length ; i++)
{
coordinates.push(polygonBounds.getAt(i).lat(), polygonBounds.getAt(i).lng());
}
}
else
{
//alert("Not polygon");/////////////
}
}
</script>
<script>
var map;
function initialize()
{
map = new google.maps.Map(document.getElementById('map'), {zoom: 12, center: new google.maps.LatLng(32.344, 51.048)});
var drawingManager = new google.maps.drawing.DrawingManager();
drawingManager.setMap(map);
google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
var newShape = e.overlay;
newShape.type = e.type;
all_shapes.push(newShape);
setSelection(newShape);
save_coordinates_to_array(newShape);
google.maps.event.addListener(newShape, 'click', function() {setSelection(newShape)});
});
google.maps.event.addListener(map, 'click', function(e) {clearSelection();});
}
google.maps.event.addDomListener(window, 'load', initialize);
</script>
</head>
<body>
<table border="1">
<tr>
<td>Name</td>
<td><input name="name" id="name" type="text"></td>
</tr>
<tr>
<td>Color</td>
<td>
<table border="1" width="100%">
<tr>
<td bgcolor="#FF0000"> </td>
<td bgcolor="#00FF00"> </td>
<td bgcolor="#0000FF"> </td>
</tr>
</table>
</td>
</tr>
<tr>
<td colspan="2"><input name="save" type="button" value="Save" onClick="draw_shape()"></td>
</tr>
<tr>
<td colspan="2"><input name="delete" type="button" value="Delete" onClick="deleteSelectedShape()"></td>
</tr>
</table>
<div id="map"></div>
</body>
</html>
Where and how can I save the created overlay shapes in the database. All shapes are saved in the var all_shapes = []; array. What kind of type I have to choose for the field in database? I mean for example int, char, etc.
I'm going to use MySQL and PHP.
Answer
When you simply want to store the shapes somehow, you may use a JSON-string, store it in e.g. a Text-column(char would be to small to store detailed polygons/polylines )
Note: when you create the JSON-string, you must convert the properties(e.g. to native arrays or objects), you cannot store for example LatLng's directly, because the prototype will be lost when saving it. Pathes of polylines/polygons may be stored encoded
Another approach: use multiple columns, e.g.
- a column(
varchar) where you store the type(LatLng, Circle,Polyline,etc.) - a column(
geometry) where you store the geometric features(LatLng,Polygon or Polyline) - a column(
int) where you store a radius(used when you insert a circle) - optionally column(
text) where you store the style-options(when needed)
The first suggestion would be sufficient when you simply want to store it.
When you must be able to select particular shapes, e.g for a given area, use the 2nd suggestion. See http://dev.mysql.com/doc/refman/5.0/en/spatial-extensions.html for details of the spatial extensions
2 functions that either remove the circular references and create storable objects, or restore the overlays from these stored objects.
var IO={
//returns array with storable google.maps.Overlay-definitions
IN:function(arr,//array with google.maps.Overlays
encoded//boolean indicating if pathes should be stored encoded
){
var shapes = [],
goo=google.maps,
shape,tmp;
for(var i = 0; i < arr.length; i++)
{
shape=arr[i];
tmp={type:this.t_(shape.type),id:shape.id||null};
switch(tmp.type){
case 'CIRCLE':
tmp.radius=shape.getRadius();
tmp.geometry=this.p_(shape.getCenter());
break;
case 'MARKER':
tmp.geometry=this.p_(shape.getPosition());
break;
case 'RECTANGLE':
tmp.geometry=this.b_(shape.getBounds());
break;
case 'POLYLINE':
tmp.geometry=this.l_(shape.getPath(),encoded);
break;
case 'POLYGON':
tmp.geometry=this.m_(shape.getPaths(),encoded);
break;
}
shapes.push(tmp);
}
return shapes;
},
//returns array with google.maps.Overlays
OUT:function(arr,//array containg the stored shape-definitions
map//map where to draw the shapes
){
var shapes = [],
goo=google.maps,
map=map||null,
shape,tmp;
for(var i = 0; i < arr.length; i++)
{
shape=arr[i];
switch(shape.type){
case 'CIRCLE':
tmp=new goo.Circle({radius:Number(shape.radius),
center:this.pp_.apply(this,shape.geometry)});
break;
case 'MARKER':
tmp=new goo.Marker({position:this.pp_.apply(this,shape.geometry)});
break;
case 'RECTANGLE':
tmp=new goo.Rectangle({bounds:this.bb_.apply(this,shape.geometry)});
break;
case 'POLYLINE':
tmp=new goo.Polyline({path:this.ll_(shape.geometry)});
break;
case 'POLYGON':
tmp=new goo.Polygon({paths:this.mm_(shape.geometry)});
break;
}
tmp.setValues({map:map,id:shape.id})
shapes.push(tmp);
}
return shapes;
},
l_:function(path,e){
path=(path.getArray)?path.getArray():path;
if(e){
return google.maps.geometry.encoding.encodePath(path);
}else{
var r=[];
for(var i=0;i<path.length;++i){
r.push(this.p_(path[i]));
}
return r;
}
},
ll_:function(path){
if(typeof path==='string'){
return google.maps.geometry.encoding.decodePath(path);
}
else{
var r=[];
for(var i=0;i<path.length;++i){
r.push(this.pp_.apply(this,path[i]));
}
return r;
}
},
m_:function(paths,e){
var r=[];
paths=(paths.getArray)?paths.getArray():paths;
for(var i=0;i<paths.length;++i){
r.push(this.l_(paths[i],e));
}
return r;
},
mm_:function(paths){
var r=[];
for(var i=0;i<paths.length;++i){
r.push(this.ll_.call(this,paths[i]));
}
return r;
},
p_:function(latLng){
return([latLng.lat(),latLng.lng()]);
},
pp_:function(lat,lng){
return new google.maps.LatLng(lat,lng);
},
b_:function(bounds){
return([this.p_(bounds.getSouthWest()),
this.p_(bounds.getNorthEast())]);
},
bb_:function(sw,ne){
return new google.maps.LatLngBounds(this.pp_.apply(this,sw),
this.pp_.apply(this,ne));
},
t_:function(s){
var t=['CIRCLE','MARKER','RECTANGLE','POLYLINE','POLYGON'];
for(var i=0;i<t.length;++i){
if(s===google.maps.drawing.OverlayType[t[i]]){
return t[i];
}
}
}
}
The array returned by IO.IN may be sended to a serverside script. The serverside script should iterate over this array and INSERT a JSON-string into the table:
<?php
$mysqli = new mysqli(/*args*/);
$stmt = $mysqli->prepare('INSERT INTO `tableName`(`columnName`) VALUES (?)');
$stmt->bind_param('s', $json);
foreach($_POST['shapes'] as $value){
$json = json_encode($value);
$stmt->execute();
}
?>
to restore the shapes fetch them:
<?php
$json=array();
$res=$mysqli->query('SELECT `columnName` from `tableName`');
while ($row = $res->fetch_assoc()) {
$json[]=json_decode($row['columnName']);
}
$res->close();
$json=json_encode($json);
?>
and pass the result to IO.OUT():
IO.OUT(<?php echo $json;?>, someGoogleMapsInstance);