How to highlight regions in a map from Google maps

 Geographical Info, Javascript  No Responses »
Dec 082012
 

In a previous post of the series on Google maps we have seen how to add markers to the map to annotate specific points in it.

Sometimes, we would like to highlight an area on the map, rather than a single point. Using the Google Maps API it is also possible to highlight an area on the map defined by means of a single polygon or a set or polygons.

Finally, if we want to highlight a path, it is also possible to do it by means of a polyline.

In this post we will explain how to highlight areas and paths on the map with Google Maps API V3, with usage examples.

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 Posted by at 9:28 am

How to put a OSM map in a web page

 Geographical Info  No Responses »
Dec 022012
 

OpenStreetMaps offers at www.openlayers.org a free service to serve maps generated from the information in the OSM database. Being a free service, it is offered without warranties of availability. If our web site is expected to get a high volume of traffic, we might be interested in other alternative services based in OSM, such as MapQuest. Finally, we can also serve the maps from our own server. This post reviews these alternatives.

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 Posted by at 6:27 pm

How to work in javascript with a map from Google Maps

 Geographical Info, Javascript  No Responses »
Dec 012012
 

This post continues the series started in our post on adding a map from Google Maps to a web page. Here we will explain how to work dynamically with the map, using javascript to modify its characteristics (center point, zoom level, etc…), and handling events generated in the map (when the user clicks on it, or pans/zooms the map).

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 Posted by at 5:27 pm

How to add location markers to a map in Google Maps

 Geographical Info  No Responses »
Dec 012012
 

In our previous post we have seen how to add a map from Google to a web page. In many cases we will be interested in highlighting on the map one or several locations or regions referenced in the page. We do this in Google Maps API V3 by means of markers.

In this post we explain how to add markers to a map, and how to process events from these markers (for instance, when the user clicks on them).

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 Posted by at 8:12 am

How to process GeoJSON files in Perl

 Geographical Info, Perl  No Responses »
Oct 142012
 

In our previous post on adding interactive maps to a web site, we talked about the GeoJSON format as a well known format for the representation of geographical information. There are many software applications that can import and export data in this format, but sometimes we might find useful to develop an ad-hoc script to process this information in a non-standard way, not implemented in those utilities.

In this post we will explain how to write a perl script that reads and processes a GeoJSON file, and writes down the processed data into a new GeoJSON file.

 

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 Posted by at 11:40 am

How to add Google maps to your site using Google Maps API V3

 Geographical Info  1 Response »
Jul 012012
 

(Leer este artículo en español)

1. Generating an API key

Google Maps V3 can be used anonymously without an API key. In this case, google enforces a limit of 25,000 map views per day per domain.
But we recommend using an API key: there are no drawbacks in doing so, and on the other hand it has the advantage of getting access to usage statistics collected by google.

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 Posted by at 10:46 am
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