OpenStreetMap: the free Google Maps

OpenStreetMap provides and allows you to create geographic data such as street maps, etc. freely so that anyone can access them. The project was created because many of the maps that we use for free and that we believe are "free", in reality, they hide technical and legal restrictions of use, preventing people from using that data creatively and productively.

I was testing it and the truth is that still not impressive but certainly promising. Those of us who know the power of open systems and know the advantages of these, can see the potential of a project with these characteristics and the importance of having such an information system.

What is OpenStreetMap?

OpenStreetMap (also known as OSM) is a collaborative project to create free and editable maps. Maps are created using geographic information captured with mobile GPS devices, orthophotos, and other free sources. The cartography, as well as the images created as the vector data stored in its database, are distributed under a Creative Commons Attribution-ShareAlike 2.0 license.

In January 2010, the project had more than 200.000 registered users, of which about 11.000 carry out some editing in the database every month. The number of users usually doubles every five months. Registered users can upload their tracks from GPS and create and correct vector data using editing tools created by the OpenStreetMap community.

Every day 25.000 new km of roads and paths are added with a total of almost 34.000.000 km of roads, that without adding other types of data (points of interest, buildings, etc.). The size of the database (called planet.osm) is over 160 gigabytes (6,1 GB with bzip2 compression), increasing daily by about 10 megabytes of compressed data.

How is the database getting richer?

The collection of information "in the field" is carried out by volunteers, who consider the contribution to the project an addictive hobby. Taking advantage of their journeys on foot, by bicycle or by car and using a GPS device, they will capture the traces and waypoints, also using a notepad, voice recorder or a camera to record the information associated with these traces or points of interest. digital photos. They also tend to interrogate passersby for their local knowledge about specific information about the place that is unknown (street names, traffic directions, etc.).

Later, and in front of the computer, this information is uploaded to the project's common database. Some committed contributors systematically map their city or population center in which they reside for long periods of time until their zone is completed. Likewise, so-called mapping parties are usually organized, in which meetings of collaborators are organized to map and complete certain areas of which information is lacking and also share experiences (they are similar events to LAN parties and community meetings virtual computing).

Apart from these organized information surveys, the project relies mainly on the large number of small edits made by the majority of contributors, which correct errors or add new data to the map.

Public data sources

The existence or release of public data from government institutions with a type of license compatible with that of OpenStreetMap has allowed this geographic information to be imported into the project database. Thus, most of the information relating to the United States comes from these types of sources, where laws require the federal government to make these data public. Such is the case of:

Images from the Landsat 7 satellite.
The vector covers of the Prototype Global Shorelines (PGS).
TIGER data from the US Census Bureau.

Various local authorities have also released their aerial photographs by making them available to the public through OpenAerialMap.

In Spain, the National Geographic Institute (IGN), a public body in charge of creating, maintaining and marketing official cartography in the country, modified it in April 2008.

Data format

OpenStreetMap uses a topological data structure. The data is stored in the WGS84 lat / lon datum (EPSG: 4326) from Mercator projection. The basic elements of OSM mapping are:

Nodes. They are points that collect a given geographical position.
The ways. They are a list of nodes that represents a polyline or polygon.
The relationships. They are groups of nodes, paths and other relationships to which certain properties can be assigned.
The tags. They can be assigned to nodes, paths or relationships and consist of a key (key) and a value (ex: highway = trunk).

The ontology of the map features (mainly the meaning of the labels) is maintained by a wiki.

From the data of the OpenStreetMap project it is not only possible to produce road maps, but also for the creation of hiking maps, bikeway maps, nautical maps, ski station maps, etc. They are also used in applications for calculating the optimal routes for vehicles and pedestrians. Thanks to its open license, raw data is freely accessible for the development of other applications.

Where can I get more information and see the maps?

To delve into the subject, I recommend that you visit the OpenStreetMap wiki.

Don't forget see the maps in your internet browser, just like Google Maps.

List of programs that run on Linux to use OpenStreetMap

gps drive is a navigation system for cars (bicycles, boats, airplanes). For now, the representation of the position on a map and a lot of other functions is implemented. GpsDrive shows your position provided by the GPS receiver with NMEA capabilities, on a zoomable map. Maps are automatically selected depending on position. You can adjust the preferred scale, which the program tries to obtain from the available maps.
JOSH (Java OpenStreetMap Editor in its acronym in English) is one of the main offline map editors that OpenStreetMap has. It is a rich editor especially aimed at experienced OSM users. It requires a bit of effort to install and configure. But if you intend to become a huge OSM contributor, it is well worth the time to get used to.
Merkaartor, another offline map editor based on Qt. Together with JOSM, it seemed like the best option.
mkgmap is a map converter in OSM format, which is what OpenStreetMap uses, to IMG format, used by Garmin GPS.
gosmore is an OSM map viewer, like the one used by OpenStreetMap. Supports almost all operating systems (Linux, FreeBSD, Mac OS X, Windows, Windows CE, Maemo, etc.)

All these programs can be installed on Ubuntu using Synaptic. Actually the list is longer, these are only the ones that I found the most useful or of the best quality. Don't forget to see a complete listing of the OpenStreetMap related programs available in Ubuntu.

DesdeLinux