Editing Standards and Conventions
The following are some Standards and Conventions for editing the maps. For basic information on how to edit, see Editing
Naming Conventions
- Street names. Enter the full name as it appears on the street name signs. Use mixed case with the first letter of each word capitalised (for example, Church Street, not Church street). Do not abbreviate words. There is currently no table of standard abbrviations (St. could be Street or it could be Saint) and until such time as a standard table has been developed it is better to enter the full name. Also watch out for apostrophes (There is no obvious consistency; the London Underground station Barons Court is adjacent to Earl's Court, one with an apostrophe, one without).
- Abbreviations. None at present.
Drawing Guidelines
Roads
| Feature | Example |
|---|---|
| A road, street,footpath etc is drawn as a single path.
In the future it will be possible to group together all the segments on a path to form a contiguously named road or street. Until that is possible it is best to just add a name to the segment at each end of the street. In the future it will also be possible to label paths to indicate whether they are freeways, streets, footpaths, etc. For the moment all paths look the same. |
|
| A dual carriageway (or separated highway) should be drawn as two separate paths. The general rule is that if it is not possible to turn across the street at any junction then it should be drawn as two paths. If there are limited turning points then these should be explicitly marked as a link between the two carriageways. |
Roundabouts
| Feature | Example | |
|---|---|---|
| A standard size roundabout with up to four exits can be drawn simply using four nodes in a diamond shape. A road can be connected to each of the nodes. A larger roundabout may benefit from using eight or even more nodes. | [[Image:StandardRoundabout.png | center|A standard roundabout with four exits]] |
| Where a dual carriageway connects to a roundabout, there should be two nodes on the roundabout in place of just one. | [[Image:RoundaboutWithDualCarriageway.png | center|Dual Carriageway with Roundabout]] |
| A mini-roundabout, comprising of little more than white paint on the road can be represented as a single node (in the future it will be possible to annotate a node as a mini-roundabout or traffic-lights etc). | [[Image:MiniRoundabout.png | center|A mini-roundabout]] |
| In many cases the road approaching a roundabout may split into two separated carriageways. If these are of a significant size (at least more than just a pedestrian island) then you may want to draw some or all of these out distinctly like the following example: | [[Image:RoundaboutWithSeparatedEntriesAndExits.png | center|A roundabout with separated entrances and exits]] |
If you want to know more about the design of roundabouts in the United Kingdom then this pdf document (Highways Agency Design Manual for Roads and Bridges - Part 3, Geometric Design of Roundabouts) is the definitive reference.
Junctions
| Feature | Example | |
|---|---|---|
| All road junctions should be drawn as a node with connecting paths. It is incorrect to add a node that appears to be on a path but is actually not connected. While this might look right, it will not define a valid path from one road to the other.
Currently there is no way of adding a node to an existing path so, if you want to add a junction to an existing road you will need to delete the segment of the existing road, add a node and then connect each end of the old path to the new node. |
[[Image:T-Junction.png | center|A simple road junction]]
 |
- Intersections and interchanges - how much detail
- Accuracy. How do you judge and or indicate the accuracy? How accurate is good enough? Is a rough approximation better than nothing (ie inaccurate roads get refined the way wikipedia articles do).
- Is it constructive/helpful to mark a road that you know is roughly in the righ place but dont have any supporting GPS data?
- Landmarks, footpaths, etc?
- How do you indicate that one road passes over or under another?
- If a road is made up of several/many segments, how often should it be labelled with its name? eg M25 - once between each junction? Once on each carriageway (M25 Clockwise, M25 Anti-clockwise)?
Accuracy
Accuracy is important. The GPS system provides fixes that can be accurate to 1-10m which is more than good enough for this project. Do bear in mind, however, that a road can several metres wide and a GPS fix could have been made anywhere in the road or even on the pavement. For many purposes accuracy to a few metres is plenty good enough. What is equally important however is topological accuracy. Do two roads intersect at the some point (a crossroads) or is the intersection offset? This detail may only be a matter of a few metres, but can be the difference between driving instructions that might say at the crossroads go straight ahead or at the junction turn left and then after 10 metres, turn right.
Topology
- Is correct topology more or less important than accurate location?
- If a road is a dual carriageway it should be show as two lines
- If a road has a small traffic island (eg at the approach to a large roundabout) should this be represented as a triangle or not? How big should it be before it should be drawn?
- Should mini-roundabouts (comprising of just white paint on the road) be drawn as a roundabout?
- Where a side road connects to a main road should there be a node with three lines connected to it or should the main road be a continuous unbroken line and the side road just ending at but not connected to a node that is part of the main road?
- If a road is can be clearly made out from the aerial photo, but there are also a few GPS tracks, which should be considered to be the more accurate?
- Should roads be drawn based solely on the aerial photo if there are no GPS track points?
Etiquette
- I see some yellow dots - I know the area - should I connect them up? A lot of tracks may have been uploaded from a source such as eCourier, so yes go ahead. If you suspect that someone else is editing in that area then it's best to edit somewhere else for a while. You can check for recent editing activity here.
- Should every road be given a name? Yes, if it has a name and you know what it is. It's much easier to add names as you go along than to draw a lattice of streets and then try to figure out which is which later. If you don't know or aren't sure what the name of a street is though, still go ahead and draw the street, someone else will always be able to fill it in later.
- WARNING: OpenStreetMap is highly addictive For some people the process of mapping on OpenStreetMap is highly addictive. Take frequent breaks, there is a lot to be done.