[GIS] Buffer Zone Algorithm

algorithmbuffergoogle mapsPHP

I use google maps, php, mysql, and I want to create a buffer zone in line among some points.

Could someone tell me where can i find the algorithm (php library or the math in order to implement it) to achieve this?

In the forum I read a lot of similar questions based on postgis and the ST_BUFFER function, i want to implement this function in php or javascript with points of google maps.

Best Answer

You shouldn't need to re-implement the wheel, there are lots of geospatial libraries out there. As you've noticed, PostGIS includes a buffer function, unfortunately MySQL has sub-standard spatial support and therefore doesn't include one. If possible you may wish to consider switching to PostGIS if spatial functionality is important to you.

There are several PHP Geospatial libraries list here for various things: http://phptrends.com/dig_in/geospatial

A search for "Javascript geospatial library" also brings up a few results. One of them is something called jQuery Geo: http://www.jquerygeo.com/

Related Solutions

[GIS] Add a polygon to PostGis from Google Maps

I'd suggest starting here. I believe the author of that tutorial to be a member of this very site, and suspect you'll hear from him as well. Good luck, and equally importantly - have fun with it.

[GIS] Markers on openlayers openstreetmap

You make mistake in loadMarkers function:

 if(jsonData.markers[i].limpio == 0)
     var icon = new OpenLayers.Icon('redMarker.png',size,offset);   
 if(jsonData.markers[i].limpio == 1)
     var icon = new OpenLayers.Icon('greenMarker.png',size,offset);

After that icon variable is undefined. You should explode this variable before if statement

var icon;
if(jsonData.markers[i].limpio == 0)
     icon = new OpenLayers.Icon('redMarker.png',size,offset);   
else
     icon = new OpenLayers.Icon('greenMarker.png',size,offset);

Probably this is why you can't display your markers. For refreshing markers better is setInterval function than setTimeout. This is sample: setInterval

edit:

In jQuery library you can call:

$.ajax({
  url: "jsonZona.php?zona=".selectBox.value
}).done(function() { 
  // Function to create markers, same as before
});

Best Answer

Related Solutions

[GIS] Add a polygon to PostGis from Google Maps

[GIS] Markers on openlayers openstreetmap

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