I am a college student majoring in cartography and has contributed to OSM for almost a year. And I also exported and used the data in a community extent to make maps for my hometown, campus etc. For large scale data exports, I used to use the free download service provided by GeoFabrik. For example, I tried to make a railway map of China with ArcGIS so I downloaded Chinese section of the database. However it was a waste of resource for the server and waste of time for me when I downloaded data I didn’t need like waterways, buildings.

Recently my teacher asked me to get urban road networks of dozens of cities distributed around the world and I happened to find overpass-turbo. The query wizard is incredibly awesome that I can query with natural language. Really easy to use! However the GUI told me the data may be too large for my explorer to handle. This frustrated me a lot. Yet, I then found the export raw data from Overpass API without visualizing them and finally got what I need. This really saved time and resource to download all the irrelevant features, what’s more, I don’t have to use the OSM API via JOSM to manually download the corresponding administrative boundaries and clip the national or regional data. The API server responded really fast than I expected, after all it’s a great deal of computation to export what I want. Sincere thanks to the overpass API as well as turbo!

As a newbie to overpass, there’s also some questions.

• Would it be too costly for the server to export an extent of a whole city?
• Is there any way for me to achieve the same goal with other better methods or less public resource consumption?

Since I finished mapping my hometown from almost white in the early September, I’ve been wondering what to map next. I’ve tried railway station sidings near my hometown but find that it’s not the most urgent to do. Then I went to my university campus. Here’s how it looks by now after my edit of ~300 ways and ~1200 nodes included in 5 changesets recently.

Situation here was quite different from that I met before in my less developed hometown where nothing has been mapped, actually, there were many features already here created by other students. It should be a good news generally, for less work is needed. However some of them are ambiguously and even inappropriately tagged, with grass tagged as meadow, dormitory tagged as hostel, wood tagged as forest, service roads tagged as track, etc. So the main work done by me is to correct them. Besides, some area was still left uncompleted for the cloud in the imagery and I mapped buildings there according to my knowledge and paper maps.

It’s quite different to map the area where many other people have worked. Correcting and updating them gave me a new experience in contributing to OpenStreetMap in China. Next step, reorganize the main line railway network in China using relations and add the missing ones according to national standard ref numbers of railway lines, i.e. GBT 25344-2010.

I’ve been actively mapping on OSM this summer vacation to complete the map of my hometown. After my effort of 20 changesets in which 2284 ways and 8989 points were contributed, there’s just 5 blocks left blank in the town of Mengjin. I intend to finish them before the new semester starting on 7th. It’s a pity that the export service is always too busy to be available and the new tiles have not been rendered to the map, so I cannot post the map picture here. :-( Here comes my question. It’s about a natural feature which is very common in my area and northwest China. Having read the cliff article in wiki, I don’t think it’s proper to tag the feature as cliff because the same doubt was put forward in the discussion whether a cliff of around 1-3 meters deep as well as not made of rock but earth can be called a cliff. As far as I know, gully is the depression with nearly vertical scarp as a result of water erosion, which quite suits my situation. Luckily I found the gully article in wiki and used it in my work. The place where I used natural=gully. However this tag in not commonly used by others and not rendered as well. I wonder if what I did was appropriate and need help. And same problem for the agricultural terrace. How do I map that cliff of low depth?