International Journal of Interactive Communication Systems and Technologies (IJICST) OpenStreetMap

Kevin Curran University of Ulster,

John Crumlish University of Ulster, Northern Ireland

Gavin Fisher University of Ulster, Northern Ireland

ABSTRACT OpenStreetMap is a collaborative project which collects geospatial data to create online freely available to anyone with access to the Internet. Once accessed, OpenStreetMap allows Internet users to contribute and edit geospatial data, making it effectively the mapping equivalent of . OpenStreetMap is maintained by volunteer cartographers from around , who use GPS devices, portable cameras and laptops for field mapping. The results are complemented with digitising and other free mapping data from the governmental and commercial sources to compile and distribute free online maps. This report provides a summary of OpenStreetMap as an outstanding example of a participatory geographic information system (GIS).

Keywords: OpenStreetMap, participatory GIS, , open mapping, , collaborative maps, citizen

INTRODUCTION OpenStreetMap (OSM) is a collaborative web mapping project—an example of participatory GIS—which makes free crowd-sourced geospatial data available to anyone with access to the Internet. OpenStreetMap was started in 2004 by , a programmer from the residing in . Using his laptop and a global positioning system (GPS) receiver, Steve Coast began mapping his neighborhood, paying attention to the locations of particular interest to him, and including much more detail than any available online service was providing at that time. He correctly envisioned that making such data augmentable, editable and freely available online, where anyone could access or contribute information, might create a snowball effect, which would eventually lead to the development of, in his own words, a “jigsaw map of the world” (Musgrove, 2010).

Since its inception, OpenStreetMap has attracted countless Internet users throughout the world who have contributed to the project in different ways. At the time of the first State of the Map (SoTM) conference set up by OpenStreetMap Foundation in July 2007 in there were only 9,000 registered users. Starting from 2007, Yahoo! allowed OSM to tap into its vertical aerial photograph database, which greatly facilitated the progress of the OSM project (in 2010 ’s also released its aerial imagery for the OSM). By August 2008, the number of registered users rose to 50,000; by March 2009, the number rose to 100,000 members; and by the beginning of 2010 the project had 200,000 members. In November 2011 the total number of volunteers reached 500,000.

Among other milestones, one should mention: (a) valuable functionality was added in January 2008 making OSM available for cyclists who started downloading map data into GPS units to use it on trips; (b) funding of 2.4 million euro became available from CloudMade, a company founded by Steve Coast, that uses OpenStreetMap data for providing commercial geospacial services; (c) in September 2009 announced that it began supporting OpenStreetMap, which allowed geotagged photos of landmarks to be uploaded to the OpenStreetMap server (Lardinois, 2009). Currently, netizens around the world utilize and update data available at the project’s website OpenStreetMap.org. Citizen cartographers range from volunteers, who as part of humanitarian relief work in disaster regions (where up-to-date maps are essential and could be a matter of life and death for the victims) to residents of cities, small towns and villages, who simply want to map their neighborhoods or highlight certain landmarks that might be of interest to others. At the time of this writing, OpenStreetMap community continues to grow with contributors across the globe submitting novel data or editing existing information.

Probably the most significant use of OpenStreetMap has come in the aftermath of the earthquake that struck Haiti on January 12, 2010 with the epicenter located 25 km to the west of the country’s capital Port-au-Prince. Pre-earthquake maps of Haiti contained little more than a few highways and roads, with Port-au-Prince being signified by a shaded outline. Haiti is one of the poorest countries in the Western Hemisphere, and as very few of the population could afford GPS, there was no point for the commercial mapping services in creating accurate digital maps. The lack of an accessible online cartographic reference had serious impeding implications for the relief efforts once the catastrophic earthquake killed hundreds of thousands of people and made close to one million homeless. International rescue and aid workers who were trying to provide much needed relief uncounted many problems identifying what roads and routes were available for the rescue and delivery of the necessary supplies.

According to the website CrisisCommons.org, there were a number of stages in the development of the inclusive Haiti maps to allow the aid workers to get help to the victims. Firstly, there was an immediate search for available maps. These included various historic maps and even maps unclassified by the CIA. Due to critical circumstances, the Public Library, which has a specialized Map Rectifier facility, provided volunteer cartographers with NYPL Map Warper, a software application that allowed for digitizing of the historic maps of Haiti and aligning them with contemporary maps. At this point, OpenStreetMap volunteers began to get deeply involved with the project. Before the earthquake of 2010, they had already collected some mapping data of the disaster areas, which were used in conjunction with historic maps. Starting from this point, the OpenStreetMap community began collecting and editing the field data and mapping collapsed bridges and impassable roads, locations of hospitals and refugee camps, as well as accurately marking the position of damaged buildings where victims could remained trapped. The next vital step involved the United Nations releasing satellite imagery of the region for public use, a move that was followed by commercial satellite overhead imagery providers such as GeoEye and Digital Globe. All these combined efforts helped to collect a vast base of cartographic knowledge, which has permitted OpenStreetMap community to build what has become the most comprehensive map of Haiti.

The Haiti mapping effort may be the most significant example of how OpenStreetMap has had a major social impact, but there are many other examples of OSM performing valuable social service for society. A large part of the success of OpenStreetMap was due to its diverse user base around the world. The OpenStreetMap official blog, user diaries and OSM forum threads contain references to a number of local or even global mapping events such, as Night of the Living Maps, a global OSM map editing marathon. The OpenStreetMap Wiki also highlights similar and smaller events. These events could be anything from a casual get-together for the novice users to explore neighborhoods using on-the-ground GPS surveys or walking papers, with collected data to be later imported and processed in the OSM editing environment; to mapping parties, where cartography enthusiasts meet with the of inclusive mapping of a particular area; or events such as armchair mapping—editing cartographic information collected in the field, working with available sets of data or digitizing aerial photography. While armchair mapping provides only a virtual camaraderie, the mapping parties are made up of a number of people who then usually split into groups of two. Using GPS units, volunteers typically start with plotting the locations of obscure roads and footpaths, local landmarks, etc. Coordinates can be recorded in handwritten form by novice users, or saved on GPS receivers by the more experienced. These coordinates are then brought to a person experienced with the OSM editing environment such as JOSM, who uploads the information into existing OpenStreetMap dataset. The main objective of these and similar volunteer efforts is to chart exhaustively by adding layer after layer of detail to a map of a designated area, and to keep it continuously up-to-date.

OPENSTREETMAP PRODUCTION TECHNIQUES The data collection for OpenStreetMap is increasing rapidly. Basically, participatory digital map production techniques stem from the on-the-ground GPS or paper surveys, intimate knowledge of a certain geographical community plus available aerial imagery. Volunteers who travel by foot, , or study the landscape using handheld GPS, a paper log, or voice recorder, and create the initial OSM data file. The project can greatly benefit from the access to the aerial photography datasets from government agencies or commercial services, and volunteer cartographers in different countries work on securing it. Technical teams are set up to manage the conversion and import the data when large datasets are available to use in the OSM. In some cases GPS would not be used if satellite imagery had been previously uploaded to the OSM server. After the upload of data, a map editor is used to edit the data.

Another important form of contribution to the OpenStreetMap project is based on editor’s own local knowledge, which allows features such as schools, libraries, various community places and landmarks, roundabouts and busy roads bypasses to be placed on the map. A number of enthusiasts who are extremely committed to the project will methodically map whole townsor rural districts over a period of time by systematically organising mapping parties to intensively map a particular area in the evenings or over weekends. A score of other volunteers correct errors and add features by performing a large number of smaller edits. This is done via built-in and stand- alone map editors.

Several governments, including the , have released official cartographic data to OpenStreetMap, counting Landsat 7 Satellite Imagery, Prototype Global Shorelines and Tiger Data. Other countries have also made available the use of detailed local aerial photography for the OpenStreetMap project through the Open Aerial Map initiative. Some commercial companies have also donated data to the project on suitable licences. For instance, the Automotive Navigation Data, a well-known provider of the digital maps for GPS-based navigation devices, donated a complete road dataset for the and partial road datasets for and . The use of Yahoo!’s aerial photography and Bing Maps is an example of a partnership with commercial map providers.

There is a long list of software that can be used in the creation of online editable maps such as OSM. The main purposes are: map rendering and representation, map data collection and management. Map editing software used in the production and presentation of OpenStreetMap came from different sources, each with its own licensing. Map rendering and presentation software comes in the form of interactive online web-based software, desktop software and mobile phone applications. OpenLayers is an open source JavaScript library for displaying map data in web browsers. It provides an API for building rich web-based geographic applications similar to Maps and Bing Maps (Surrey councils open access, 2010). Slippy map interface is used to display map tiles rendering by other software such as Map OS Matic, which can generate city maps by using OSM data with the map split in squares allowing to easily look for streets and an index of the streets with references to the squares on the map. Other examples of such software include , Osmarender and Cartagen.

Kosmos, which is currently being replaced by Maperitive, is an example of a lightweight OpenStreetMap rendering platform providing many tasks, including the ability to render OpenStreetMaps interactively, print the maps, set up a local tile map server, create separate map rendering rules or share rules stored in OpenStreetMap Wiki pages, view maps on a Java enabled mobile phone and to perform tasks from the command line (see Figure 1).

Figure 1: Kosmos OpenStreetMap rendering platform.

Other map rendering and presentation software applications created for use on mobile phones and GPS devices include AndNav2 and for Android smartphones; OpenTouchMap, which is a is a slippy map optimised for touch screen devices such as iPhone; and finally, GpsMid which is a Java ME application that is a free, fully offline, vector-based map application for mobile phones. It displays one’s current position on a zoomable map and can be used to search for and navigate to roads or points of interest.

A prime example of mapping and data collection software that is most commonly used for OpenStreetMaps is GPSBabel, which many contributors use to convert GPS track data from various proprietary formats to the GPX format that OpenStreetMap requires. GPSBabel is a cross platform, to transfer routes, tracks and waypoint data between GPS units and mapping programs. It can convert over a hundred different types of GPS data formats. GPSBabel grants users the ability to freely move their own waypoint data between the programs and the hardware they choose to use.

In OSM there is no option of categorising what is uploaded (e.g., whether it is a road, or a river) therefore, the data needs to be edited. The volunteers perform this task with the use of map editing software. The most commonly used editing application for OpenStreetMap is JOSM, the original Java OpenStreetMap desktop editing software application (see Figure 2). JOSM is a feature-rich editor with an interface that can seem complex at first. It also requires a certain installation and configuration efforts to get some plug-in features when working particularly with Yahoo! imagery.

Figure 2: JOSM using Yahoo WMS Plug-in.

The user can utilize JOSM software to perform the editing of place names, building locations, add photo imagery and more. It is an essential application for the users of OpenStreetMap (as shown in Figure 3).

Figure 3: JOSM displaying OpenStreetMap data and GPS track logs.

Other map editing applications available for users of OpenStreetMap include Potlatch, an online flash editor; Merkaartor, a desktop editor similar to JOSM; OSM2Go, a mobile/desktop editor; and Quantum GIS, another desktop editor which includes an OpenStreetMap plug-in. The OpenStreetMap interface is easy to navigate and it is visually appealing. It includes a built-in search to find places. Overall, OpenStreetMap offers many functions and features allowing users to edit maps, review recent edits, export map data, view and upload GPS data, and make comments and suggestions.

INTERACTING WITH OPENSTREETMAP There are various methods to augment and edit the data in OpenStreetMap. Each individual method is geared toward the individual technical skills of users, and also depends on how much time and effort the user would like to contribute. A range of online and standalone editing software applications, the most frequently used includes Potlatch, JOSM and Merkaator, support the OSM project.

Potlatch The Potlatch 2 is the OSM default online editor, which opens when an Internet user goes to the edit tab on the OSM interface—utilizing any major browser and requiring only a Flash plug-in. It allows the user, for example, to work with the satellite imagery provided by Yahoo! and Bing for the purposes of creating a map of a neighborhood. By double-clicking on the image, the user creates what is called a node. A node can be used to highlight any single on the map, such as a building, and can be used in conjunction with other nodes. To complete the map, the nodes are connected using waypoints. In the latest version of OpenStreetMap, many public amenities such as telephone boxes, bus stops, etc, have their own highlighting icons, which the user simply needs to drag from the toolbar, and drop onto the required place on the map to mark their location. If a particular point of interest does not already have a designated icon, the user can simply double click the correct location on the image, creating a node. The user can then manually add the description of that particular point of interest.

Roads, tracks and pathways can be added to OpenStreetMap in a very similar way to places. The user simply has to identify the road, etc, on the Yahoo! or Bing overhead image. Single clicking at the beginning of a road will produce a node. The difference from the “point of interest” entry is that once the user moves the mouse pointer, the movement is traced with waypoints. Another single click will produce another node, and the tracing will continue from this point, allowing the user to negotiate the tracing of bends in a motorway, road, track etc. Once the end of a particular road has been reached, a double click will enter a final node that will signify the end of that particular entry. The user is then free to enter the necessary details, such as what type of road it is, motorway, connecting road, cycle path, or footpath, and any names that the entry may have, such as M1, Dunfield Terrace, etc.

Once all the information that the user wants to include has been added, they are provided with the option to save the changes that they have made for editing later, or to save the changes and upload them to the OpenStreetMap server. After the changes have been uploaded to the OpenStreetMap server, other members of the OpenStreetMap community can then review and edit them if necessary.

Java OpenStreetMap Java OpenStreetMap (JOSM) is an individual stand-alone software application that allows OpenStreetMap users to render GPS data. This information can then be uploaded onto the OpenStreetMap server. The user can either download existing data associated with the area on the map that they would like to edit or augment, or they can edit and upload their own raw GPS data to JOSM. This would most likely be decided when establishing exactly how much data already is available for a particular area. For example, the accessible data, such as satellite imagery and existing OpenStreetMap entries, for major cities and their surrounding areas is usually quite detailed. With this in mind, it may be helpful for the user to reference the existing data when making their own entries, as it will enable them to establish how accurate their GPS readings are— if need be—as well as establish whether the data they have compiled about particular items (streets, landmarks, points of interest, etc.) already exists within the server. The user may find that the current data contained within the server may need to be updated. On the flip side, as some urban areas in the United Kingdom are having quite detailed cartographic information available, some others, for example, City in the Northern Ireland, has very little. The satellite imagery available for the Derry City is poor and the information exhibited on the OpenStreetMap is quite minimal for anywhere other than the city center. With this in mind, users wanting to update data associated with an undermapped urban area such as Derry City, or others, may need to collect and upload the raw data from their GPS to JOSM.

When using JOSM, the user will initially gather as much GPS data as possible using a GPS unit. This information is then imported into JOSM as a GPX file. The coordinates of the GPX file can then be read by JOSM, and this in turn allows the user to retrieve any existing data on that particular area from the OpenStreetMap server. The information that is added is actually a series of coordinates. These coordinates can then be traced over by the user creating nodes. These nodes can then be used to signify an individual object, such as a street postbox, or as part of a series of nodes, or waypoints making up a road or a track, etc. Photos or images, such as a statue, street sign, building etc., can also be uploaded, giving the user additional information on a particular location. Various types of information may be included about each of the nodes and waypoints. For example, if a node signifies a street postbox, information should be entered to detail that it represents an amenity, and that it is indeed a postbox. If a series of nodes and waypoints signifies the location of a road, then the user should enter details of the type of road it is, e.g. motorway, residential, cycle path, footpath etc., the name if applicable, and whether it is one way or not. JOSM uses a uniform tagging system, which encourages users to tag all features on a map in a consistent way.

Merkaator Merkaator, like JOSM, is a stand-alone map editing software application that allows users to access, add and edit the datasets stored on the OpenStreetMap server. Once the data has been retrieved, Merkaators’ mapping functions are very similar to that of JOSM, in that it deals with nodes which are used individually to signify points of interest, or as a series to create waypoints signifying roads and paths etc., which can in turn be linked to Yahoo! or Bing satellite imagery. It has an intuitive user interface, providing a transparent display of map features. However, Merkaator places more emphasis on the aesthetics of mapping, since it allows the mapping more precisely curved roads. On the other side, the OpenStreetMap Wiki warns that this application, still being in the phase of development, is “very memory hungry and can freeze the machine while page- swapping” (Comparison of editors, 2012).

DISCUSSION AND CONCLUSION Given that a lot of mapping information with a high level of detail is now available online via MapQuest, Google, Yahoo! or Bing maps, it is worth asking the question, what is the benefit to regular Internet users to have access to free editable maps such as OpenStreetMap? It is important to recognize that the OpenStreetMap project has had major influence on the attitudes both of the citizens and governments towards the issue of cartographic data availability and accessibility. For example, over the past years, there has been a campaign in the UK spearheaded by The Guardian newspaper to make cartographic data collected by government-funded organizations freely available to the public. The argument is that, if the taxpayers’ money paid for the data to be collected, why should the taxpayer have to pay any more for the access. This in turn has resulted in , the UK national mapping agency, making maps in several formats available online for free downloads from April 2010 (Sung, 2010). The Independent newspaper (OS Maps, 2010) wrote that Sir Tim Berners-Lee, the founder of the World Wide Web, advised Prime Minister Gordon Brown on allowing publicly funded map data to be freely available in an effort to entrepreneurship and kick-start cutting-edge technology enterprises in the United Kingdom. According to Dr. Christopher Board, chairman of the Charles Close Society for the Study of Ordnance Survey Maps, having free Ordnance Survey maps at the user’s disposal is very important. Board claims that if it was left up to the providers to map what they felt was important, then the “most popular tourist areas would be mapped regularly and kept up to date, but there would be huge areas of agricultural land, moor or croft that would be left untouched” (OS Maps, 2010). A major advantage that OpenStreetMap would have over any Ordnance Survey maps would be that it has the potential to be updated in real time. Ordnance Survey maps can only be implemented as a point of reference for the user, however if any drastic changes may occur within the landscape of the area mapped, this effectively renders the map out of date and it is up to the Ordnance Survey cartographers to provide updates. On the other side, under the direct influence of the OSM, Ordnance Survey started to provide more free services, such as OS OpenSpace, which allows the embedding maps of Great Britain into web pages.

The practices of commercial online map and image providers have also been influenced by the OpenStreetMap project. As mentioned, first Yahoo! and then Bing Maps permitted volunteer mappers to use their proprietary aerial photography as a backdrop. Yahoo! Flickr also allows tagging the photo images with OSM tags to be easily searched and transferred on the OSM maps if needed. At the 4th annual international State of the Map 2010 conference, MapQuest, owned by AOL announced that it decided to become “the first major mapping site to embrace and encourage open source mapping at scale.” (MapQuest Opens Up). As part of this initiative, MapQuest founded an open source project – open..co.uk mapping site – based on the OpenStreetMap data. Additionally, in 2008 Google started its own OSM-type collaborative project called . According to the Times newspaper (Blakely, 2008), this service is aimed mainly at amateur cartographers based in “hyper-growth countries” like India, where the infrastructure has a tendency to change at an alarming rate in comparison to more developed countries. It was felt by Google Map Maker creator, Lalitesh Katragadda, that Google’s “enormous online reach” would be the deciding factor on which would ultimately become the most popular between this facility and similar non-commercial applications such as OpenStreetMap. Four years later, Google Map Maker is available in 188 countries and its community reached 25,000 members. Google Map Maker invites Internet users to correct and update and provides step-by-step instructions and technical support. However appealing and functional Google’s mapping applications may look, one should remember that they serve as a means of generating corporate revenue and not the altruistic purposes of mapping the world. On the other hand, OpenStreetMap project allows for uninterrupted programming access to its datasets and provides a foundation for similar crowdsourced initiatives such as Information Freeway, OpenCycleMap, OpenBusMap, OpenRouteService, OpenOrienteeringMap and other projects.

Currently, the OpenStreetMap initiative is growing and expanding with new volunteers joining the effort to build and maintain a free to use comprehensive map of the world. With continuing advances in GIS technology and new approaches to gathering and editing digital cartographic data, the seemingly utopian project steadily moves towards fruition as time goes on. New features for OpenStreetMap are being added, more areas in developed countries are getting covered and more and more developing countries are getting involved with the OpenStreetMap mapping project. Citizen cartographers are enthusiastically exploring unorthodox ways of using OSM, from highlighting the location of a communal event, to keeping a crisis map up-to-date helping a humanitarian or relief mission. The catastrophic earthquake in Haiti in 2010 has shown how powerful participatory and activist cartography can be when properly channeled and implemented. A major contribution to the success of OpenStreetMap work during the Haiti crisis is that OSM gave remote volunteer cartographers and onsite relief workers the ability to work together and update geographical data on the OpenStreetMap in real time. Despite the fact that much of the earth is yet to be mapped, OpenStreetMap already serves as a remarkable example of public participation GIS and one of the largest collective endeavours in the history of human civilisation.

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