Suppose I want to map an area, and I have lots of data (from aerial imagery, and other authorized sources), and that it will take (for example) 1 full work day to do it.

Using JOSM, I download the area from the OSM database, and almost nothing comes up (as expected, as it is an remote area), and I start editing it.

What should be the interval between saves and/or updates? It is not very likely, but if other users come and edit the same area, adding data, the changes will overlap.

Should I upload everything at the end (after one day of editing) or should I upload it in parts (let's say, every hour)? Or should I upload everything at the end of the day, but updating/refresing the downloaded data a few times along the day to see if there are changes made by other users?

When I used Potlatch 2 instead of JOSM, this never was an issue (for me). However, there were cases of changes appearing "from nowhere" when the map was dragged because some other user edited the same area.

asked 19 Oct '12, 00:07

MCPicoli's gravatar image

accept rate: 24%

closed 09 Oct '13, 19:46

The question has been closed for the following reason "The question is answered, right answer was accepted" by MCPicoli 09 Oct '13, 19:46

I suspect the answer is a mixture of both uploading at intervals (which lets other mappers see that work is being done in the area) and downloading again at intervals (as uploading won't download new or changed objects in an area). The frequency will depend on how likely you think someone else will be working in the same area. You might just get away with downloading the area again just before uploading to check nothing else has been added in the meantime.

If you are worried about other users amending things that you are also working on then JOSM does have a conflict resolution dialog, but don't always just take your version as it might lose important changes from the other user. It is easy to use, but often difficult to use correctly.

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answered 19 Oct '12, 08:53

EdLoach's gravatar image

EdLoach ♦
accept rate: 23%

If you edit for more than an hour without saving (uploading) you are risking losing your edits - all computer software complex enough to be useful is complex enough to have bugs. Saving often has no real downside. Saving often has the advantage of being able to describe the upload with a specific changeset comment to describe what you did. I would mentally divide the area into sections or areas or types of edit and save at the end of each one. If you have edited more than about 500 objects I'd think about saving too.

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answered 19 Oct '12, 11:22

ChrisH's gravatar image

accept rate: 15%


I generally agree with your recommendations, but saving and uploading are not the same thing with JOSM. I save (on disk) every few minutes, but upload (to the server) only when one self-contained task is complete.

(19 Oct '12, 15:26) Tordanik

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question asked: 19 Oct '12, 00:07

question was seen: 3,109 times

last updated: 09 Oct '13, 19:46

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