User:Bgirardot/West African HOT Mapping Tips
If someone sent you a link to this page or included it in validation or invalidation comments it means they really appreciate your work and think that maybe by reading some of the tips on this page you can increase the value and helpfulness of the data you are creating by mapping.
This page is intended to be the shortest possible set of notes you need for typical HOT task mapping in West Africa. It assumes you know how to use an OpenStreetMap editor of your choice to outline an area, draw a road and add tags to them.
If you are using the iD web editor, and would like a full walk through of its features, here is a link to a short tutorial (multiple languages offered): http://learnosm.org/en/beginner/id-editor/
If you are using or ready to get started with a more full featured, stand alone editor, here is a link to getting started with the JOSM editor (multiple languages offered): http://learnosm.org/en/josm/start-josm/
If you have any questions about mapping, you can always ask on the HOT Email List, or if it easier, just send me a message directly via my OSM user profile: https://www.openstreetmap.org/user/bgirardot
Small Village and Road Mapping
General Road, Track and Path Mapping
Issues with Mapping Buildings
Accidentally Sharing Nodes with Other Objects
Square The Corners and Exactly Map The Footprint
Interesting Features to Map
Cassava (Manioc) Crops
Aerial imagery often shows cassava plantations as rounded light green patterns, planted in not very regular rows (new plants). Sometimes it will show only brown rounded remains, but in the exact place where there were plants that were already picked.
It is farmed from side to side on the same uncovered land seasonally so its allotments usually are permanent.
Since it is usually planted in small strips or areas by few individuals, usually not large areas managed by machines, the areas are sometimes isolated or sometimes following river margins or wetland.
They should be mapped as one area when brown and green areas are together since they are part of the same seasonal plantation area. Only when they are disconnected by remarkable different features such as portions of forest or rivers or non-farmed land should they be mapped as individual areas.
Paths can be found going through the areas. Plantation borders almost always can be ways for paths, if in straight patterns and not too close to dense vegetation.
They should be tagged as landuse=farmland and crop=cassava.
As always if you are not sure, please feel free to send a url to the HOT email list, past it in the IRC channel and/or put a fixme=confirm tag on the area.
Cemeteries are difficult to identify from aerial imagery and are not very common in rural areas. If you do find what you think is a cemetery it would be best to ask on the HOT email or irc to have others look at it as well.
Marketplaces can be difficult to identify. The most important thing to see when giving them a preliminary identification is that they are a collection of very small buildings which are really very small market "stalls" or tents. It is important to see other buildings around them so you can compare the relative size of the structures. In some very high density low income areas the housing can be almost as small and just as densely packed with the roofs appearing to be one huge buildings, but in low income city housing the areas covered are usually much larger. As always, a fixme=confirm tag should be used unless you are very sure, usually with firsthand knowledge, that it is a marketplace.
The illustrations and descriptions for this section were contributed by Sonali Agrawal.