OGF:Making a topo layer
This page is intended to help users who are interested in creating a Topo Layer for their territory (or part of their territory).
Unlike most other aspects of mapping in OGF, making a Topo Layer does not involve directly uploading contour lines to the OGF database. Do NOT upload contour files to the OGF database!
What is a Topo Layer?
A Topo Layer is a display overlay (really a kind of background) that includes contour lines and/or topographic shading. On the real world's OSM homepage, the "Cycle Map" Layer includes topographic information. Examples of currently existing uploaded contours in the OGF "Topo" Layer are these:
- Roantra (by Thilo)
- Khaiwoon (by Thilo and isleño)
- Southeasternmost Ardisphere (by Luciano)
- Tąpi Rā (OIOI) (by Ūdilugbulgidħū)
- January Islands (by Luciano)
- Tárrases (by Luciano)
- Northwestern and West-central Ardisphere (by Luciano)
- Villa Constitución Region Re-factor, Ardisphere (by Luciano)
- Makaska (by Luciano)
- A peninsula in the Ghon Empire (by Ūdilugbulgidħū)
- Kezepolan archipelago (by Ūdilugbulgidħū)
- Doredo (by Ūdilugbulgidħū)
There are several methods for creating a Topo Layer. For now, this page will focus on one of those methods, which involves manually drawing contour lines.
- . . . Other methods for creating a Topo Layer may be added later.
Finally, try to avoid the temptation to use patterns of vegetation to indicate elevation. Although it is true that vegetation patterns follow elevation to some degree, it makes for an unrealistic map when ground cover is directly used to indicate elevations, as has been done in some areas of OGF (e.g. natural=bare_rock for highest elevation, natural=heath for intermediate alpine elevations, natural=wood for lower slopes of mountains, etc.).
The Contour-line Method
It is possible to draw contours using JOSM. Here is a screenshot of a detailed contour-drawing project (currently incomplete) by Luciano.
So, here are the steps to follow if you want to make a Topo Layer by drawing contours in JOSM.
- Download JOSM, and get comfortable using it for regular mapping projects. This include: you need to understand and get comfortable with working in different layers in JOSM.
- Draw some contours in JOSM, as a seperate layer. As an example, a fully complete .OSM contour file is available here. This file is the contour file used to upload contours for Southeasternmost Ardisphere, referenced above. You can save the page as-is directly to your computer (right click, "save as" on Windows), with a .OSM extension, and then open it in JOSM, and look at how the contours are drawn and tagged, comparing it to the result on the map.
- The contours are tagged with
- The contours are tagged with
- Save your contour layer (on your computer - again, please, do NOT upload contour files to the OGF database!) as a .OSM file. Compress the file ("zip" or some other utility).
- Email your compressed .OSM file to email@example.com, with a subject reading "Contour file for possible upload".
- Wait for someone on the admin team to take a look at your file and, if it is free from major errors, it will probably be uploaded to the Topo Layer on OGF. This may take quite a bit of time - there are some programs that need to be run, and everyone is sometimes busy with other things. Give at least a week. If there are problems with your file, someone will let you know.
One fun benefit of uploading a topo layer is that you can experiment with viewing your map-work in 3-D, using the OpenGlobus Sandbox: e.g. Tárrases.
If you have questions, feel free to ask on the talk page here, or contact Luciano... I am happy to try to help, but I expect you to make an effort - I will not hold your hand through the process. Learning JOSM to the point where you can be comfortable drawing contours is a lot of work - it took me 2 years to reach that point. Don't give up too easily.