#OSM Tracing Guide for Khayelitsha, South Africa
Khayelitsha is a slum in Cape Town, South Africa, where the American Red Cross and its partners will be piloting a solar-powered fire sensor system. Fires regularly occur in urban slums like Khayelitsha, often resulting from indoor stove use, trash burning, faulty wires and residents trying to keep warm. Evacuation can be very difficult, making fires a very dangerous event.
The results of this mapping will guide fire sensor program decisions/planning and will be used by firefighters during their response operations.
This tracing guide focuses on the most important features in the area: buildings and roads.
##Getting started
There are a few types of aerial imagery available and iD editor should default to using Bing. If your imagery looks blurry or hard to see, use the menu on the right side of the screen and double-check that imagery is set to Bing aerial imagery. You can also brighten the imagery here, if it's difficult to see.
The area is very dense, so zoom in as much as possible to do the mapping.
##Buildings and walls
###Understanding what's what.
We're interested in the following types of area:
- Buildings. These will look like "normal" structures, with roofs, walls, etc. These vary a lot - they may be constructed from metal, wood, or primitive materials.
- Buildings under construction. These will look like walls, but about the size of a building and with partitions for rooms. These could be dark (indicating that a foundation has been dug), lighter (indicating a filled-in foundation, maybe with short walls), or white with shadows (the walls are getting taller)
###Tracing buildings
To trace, select the Area tool (Shortcut: 3) and draw around the building/wall. Double-click to finish. Be careful not to connect roads to buildings. The process looks like this:
Next, we classify (or "tag") the building, using the buttons on the left side of the screen. Every complete (ie not under-construction) building should be tagged as "Building". A list of building types will appear - click "Building" one more time:
Buildings under construction are tagged as "Building under construction". If you don't see this category, try searching for it in the search box:
Note that once you've traced a building, you can square the corners easily by hovering and clicking the icon (Shortcut: s)
##Roads
First we trace them, then we classify them. The whole process looks like this:
###Tracing roads
To trace a road, use the Line tool in iD Editor (Shortcut: 2) and trace along the middle of the road. See below for an example of too few nodes (left), too many nodes (center), and the right amount of nodes (right).
Make sure the roads connect to each other where they cross. You should see a node appear at each intersection (see below).
###Classifying roads
The majority of roads you see in Khayelitsha should be tagged as residential. This is used for roads in residential areas where a car can pass through.
Larger, busier roads connecting towns should be classified as tertiary (minor highway), secondary (larger highway), or primary (main national highway).
For smaller pathways: classify the road as track if it looks too small/rough for a car to drive on it. For paths where not even a 4x4 could operate, use path.
If you really aren't sure, ask a Red Cross staff member or Missing Maps volunteer for help. If you can't find anyone to assist, then classify the road as unclassified:
That's it! For more resources, see: