Organised Editing/Activities/Bhutan mapping
Mapping Transport Networks for Accessibility in Bhutan
Background
The World Bank’s Poverty and Equity Global Practice (ESAPV) is engaged in a series of projects in Bangladesh, Bhutan, and Nepal to relate accessibility to key services to economic and welfare outcomes using the tools and concepts of economic geography. A foundational aspect of this work is modelling accessibility using geospatial analysis tools like network analysis and cost-time modelling, which model anticipated travel speeds over geospatial transport network datasets. High-quality, complete, and well-crafted transport network data is required for such models to return accurate results and is, therefore, critical to the overall success of these projects.
However, the World Bank ESAPV team has also noted a number of errors, gaps, and omissions in the available transport network data for each country.
For this purpose, the World Bank has contracted Kathmandu Living Labs (KLL) to observe and correct errors and missing transportation data in OpenStreetMap (OSM) of Bhutan. The main objective of this effort is to create missing transport data – principally road and path networks – in focus areas of interest (AOIs) provided by the World Bank in the form of polygonal shapefiles.
Contact
You can contact us through our email [[1]] or Ro Sun in case you have questions about this project.
Hashtag
We will use #kll #esapv #worldbank #kll_mapping_road_in_bhutan while uploading data in OSM
Timeframe
This initiative started on February 7, 2021 and is expected to be completed by February 28, 2021. Kathmandu Living Labs trained mappers are mapping in this project. Similarly, a team of highly experienced mappers from Kathmandu Living Labs are validating the data
Tools and Data Sources
Mappers are using HOT Tasking Manager and JOSM to map buildings using high resolution Maxar Premium Imagery. The area of interest (AOI’s) has been provided by the World Bank Group. We will put links to all the links to the tasks once the project is completed.
Tagging Schema:
highway=trunk: A major road connecting two or more cities mostly national highways.
highway=primary: A road corridor that carries a huge volume of traffic between arterial roads and has a high density of public transport services.
highway=secondary: A collector road that carries a lower volume of traffic and has either no public transport service or a lower density of public transport service.
highway=tertiary: A motorable road serving several villages that connects rural areas to cities.
highway=residential: A road accessing or around residential areas.
highway=path: A foot trail that connects two or more villages as well and paths inside the community that is accessed through the foot.
bridge=yes and layer=1: A bridge is a structure built to span a physical obstacle, such as a body of water, valley, or road, without closing the way underneath https://wiki.openstreetmap.org/wiki/Key:bridge
ford=yes: A ford is a small part of a highway where a waterway runs over it. https://wiki.openstreetmap.org/wiki/Tag:ford%3Dyes
Participants
KLL recruited mappers and its staff can only access the tasks. Altogether 14 mappers are mapping the tasks and 4 experienced mappers from KLL are validating the data. Following are the OSM usernames of the mappers.
Mappers
| Mappers | Data Validators | ||
| Full Name | OSM Username | Full Name | OSM Username |
| Yukesh Byanjankar | Yukays | Roshan Paudel | Ro Sun |
| Rabi Shrestha | frozenrabi | Manoj Thapa | Manoj Thapa |
| Ajaya Dhakal | Ajaya Dhakal | Rabin Ojha | Rabin Ojha |
| Prajwal Sharma | prajwalS | Sushma Ghimire | SushmaGhimire |
| Pragya Pant | Pragya Pant | ||
| Bijay Dewan Rai | Bijay Dewan | ||
Post-Event Clean Up
We have ensured data quality from the start through a periodic and rigorous data validation process. Mappers and data validators meet every day to discuss and reflect on issues and resolve them in order to ensure consistency in data creation and produce high quality data.
Map data is validated in two stages:
By mappers
Before uploading data to OSM, mappers run validation in JOSM and resolve errors related to road. This include:
- Self-intersecting roads
- Roads connected with buildings
- Crossing waterway and highway
- Ways ending near another way
- Highway terminated into area
- Bridge not tagged properly
- Missing tags
Once these errors are resolved, the mappers upload the data to OSM and mark the tile as ‘mapped’ in Tasking Manager.
By data validators
Experienced mappers from KLL validate the ‘mapped’ tiles. Errors related to roads, if found any, are resolved and uploaded. Next, they verify the correctness of the data. This includes:
Ensuring quality data
Validators check the correctness of the road traced through the Maxar premium imagery overlaid with data mapped by the mappers. If validators are satisfied with the quality, they, then, move towards the criteria of map completeness. In case of a few errors, the validators correct them. If there is a significant number of errors, the tiles are marked as “well mapped”.
Ensuring completeness
Once the validators are satisfied with map data quality, they check for missing roads in the imagery. Once they are satisfied, the tile is marked as ‘validated’; else it is marked as ‘invalid’, upon which mappers will have to map the tile again.
Results:
Till February 22, following are the statistics of the project:
- Total road created: 2340 km
- Total bridges created: 36
| Category | Length (km) |
| Path | 1360 |
| Tertiary road | 542 |
| Residential road | 4002 |
| Secondary road | 33.5 |
| Trunk | 2 |
| Primary | 1 |