04 Dec 2020
Until a couple of decades ago, map making was a reserve for experts. It was upto surveyors, geographers, and cartographers to collect and transcribe information of the physical world and make it accessible through atlases, globes, and paper maps. However, in recent years, with the rise of web technologies, this is no longer the case.
OpenStreetMap (OSM) is a free and editable digital map database of the world. It is a crowdsourcing project that relies on volunteered geographic information (VGI). Data in OpenStreetMap, which is provided through open licences, is freely availaible for visualization, querying, download, and modification purposes by anyone who needs it.
OSM is similar to Wikipedia in the sense that anyone with an account can add, edit, and delete data present in it. Since its inception in 2004, the project has receieved contributions from more than seven million users.
To add data to OSM, mappers use different software tools such as JOSM, ID editor, etc. These tools allow users to trace points, lines, and polygons on top of freely available satellite imagery and mark them as bus stops, roads, or parks respectively (see image below). Upon completion, users submit these changes online to the OpenStreetMap server.
03 Dec 2020
This segment is taken from the article “OSM: The simple map that became a global movement” originally written for Directions Magazine by Diana S. Stinton
Who are the mappers?
As of today, over 7 million people have registered with OSM to add or edit data. During the last few years, there usually have been about 25,000 different people each month who are active mappers. That sounds like a lot of volunteered geographic information, but in reality there are a few people who contribute much and many more people who contribute little or nothing. This produces the type of familiar long-tail distribution consistent with many volunteer efforts.
One unique feature of OSM is the digital fingerprints of its contributors and editors. Scholars have begun to examine these historical records to better understand the patterns of who has contributed what and when. To study “the crowd,” geographer Sterling Quinn is using the data from individual contributors in several small cities across several countries to classify, compare and contrast the frequency and type of edits. His Crowd Lens for OpenStreetMap tool (in beta version) enables users to systematically compare the individual entries over time. With information like this he has begun to categorize contributors by their motivations, including casual or systematic mappers, casual or systematic fixers, and those who participate because they have a particular connection just to that place. Those who add and edit data associated with crisis and other humanitarian events are another large group.
What are they mapping?
The very first contribution to OpenStreetMap was probably a road. The road network has been an obvious starting place for mappers given its central role in transportation, navigation, emergency management, routing, etc. It’s also a relatively easy type of map element or feature to “trace” — which is the primary way of data entry. Using one of several editing interfaces, the way one creates data is to look at an aerial photograph of a place in the world and trace along lines (roads, streams, paths), or around areas (buildings, playgrounds, forest patches) that one can see in the photo; in the OSM lingo, these lines and areas are ways.
What about points? Sure. Flag poles, fire hydrants and obelisks become nodes in the system. When ways and notes fit together or have some kind of functional relationship, such as sections of a connected trail network, or a train station and the tracks that lead from it, topology can be indicated via relations.
But the real added value of data are the attributes or map features that the local community continually adds as tags to the geometric data that have been captured. It’s not just the polygon shape of a building that is important: it’s all of the additional information about the nature and functions of the building and the services it provides within. It’s not only that a structure has been mapped, but knowing that it is a commercial structure that does car repair on Volvos. Or that a particular ATM node is associated with the Bank of America and can or cannot accept cash deposits.
The level of detail now possible to attach to each segment of a roadway is formidable. Names, surface types, speed and weight limits, and even very localized restrictions on passing are some of the possible attributes to associate.
Entering the geometry of features, by tracing what is visible, can technically be done from anywhere and by anyone. But the more precious commodity is the local knowledge associated with the attributes, even if it is just the names of the roads. For example, Mapzen’s Indy Hurt has documented the expanding collection of OSM data in three Indian cities. The overall cumulative length of the road network and number of buildings are simple metrics that show growth, but the increase in the tags themselves is stronger evidence for the enrichment of the data through local knowledge. One single, long road is of lesser interest than that same length that has been dissected into its constituent segments, each with its own collection of tags.
02 Dec 2020
OSM has a strong and active community in Nepal, with organizations such as Kathmandu Living Labs, Youth Innovation Lab, and Naxa conducting mapping activities throughout the year. In addition, there’s a lot that you can do dependending on where you’re from:
If you are a government/non-government organization:
- You can provide your data to OpenStreetMap. Thousands of websites and publishers use OpenStreetMap as their source for geographical data. These include companies like Facebook, Microsoft, Apple and Amazon. Getting your data into OpenStreetMap would simultaneously allow you to:
increase the reach of your data,
engage the active OSM community (6 million global users, 16,000 active users everyday) in its maintenance, and
take advantage of thousands of tools within the OSM ecosystem.
- You can launch a city mapping project. The World Bank’s Open Data for Resilience Initiative (OpenDRI) was started in Nepal, and provides guides to launch city mapping initiatives.
- You can start and/or support a local mapping community. Join the OSM Nepal facebook group to learn more.
- You can generate digital and printed map books using OpenStreetMap data.
If you are a college/university:
- You can conduct OSM workshops for students and faculty.
- You can support student chapters dedicated to mapping. YouthMappers is a global organization that can help you do this.
If you are a student/volunteer:
- You can learn about OSM. This entry for OpenStreetMap in wikipedia, and the website LearnOSM.org is a great place to start.
- You can learn how to map. This website contains a range of beginner to advanced tutorials on OSM.
- You can learn about what’s happening in the local mapping scene by joining the OSM Nepal facebook group.
- You can volunteer your mappings skills. The Humanitarian OpenStreetMap Team is always looking for mappers to support their mapping initiatives across the globe.
01 Dec 2020
In this guest post, OSM mapper, geomatics engineer, and KLL team member Sushma Ghimire talks about her experiences with mapping.
Hello there! I am Sushma Ghimire, a recent undergraduate from Kathmandu University, Nepal. I have been an active OSM contributor ever since I joined Kathmandu Living Labs in July 2020 as a Geospatial Analyst Intern. Prior to joining KLL, I knew very little about OSM: to me it was open and mapping platform and produces freely available digital maps. As I started contributing more, I came to know about its uses and significant impacts all around the world. I learnt that even a small rectangular polygon mapped in OSM, can symbolize buildings and people living in it, and consequently draw the attention of decision makers.
The journey from being a beginner to advanced mapper and OSM data validator has made me thoughtful of many little things that I had no idea about. My initial days in mapping was the remotely based armchair mapping and preparing the foundational/base features of maps like buildings and roads in eastern Nepal, mainly Province 2 with an objective to prepare it for disaster and develop resilience in the province. These spatial datasets were expected to help the frontline workers and first responders reach the affected areas post-disaster and prioritize aid. I learnt that these datasets could also be useful for government teams to identify where vulnerable populations are and provide them with a way to track and visualize risks. I was really amazed knowing that my small contribution from the chair had such a high level impact in places that I have never physically been to, directly touching the lives of people who I had never met. Additionally, I also contributed to OSM as a local mapper and mapped my own street. I could easily identify the type of buildings, amenities, roads and other several features on the map in my own area and fill in the details for these underlying base features. As such, I was directly contributing to my own area too for a social and humanitarian cause and it is something one can really boost about and be proud of.
What I like about OSM is the fact that anyone can map in OSM. Anyone can contribute both to places where they live and or places they have never been.