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Is there any way to filter the data before it is downloaded into JOSM? Suppose, for example, I wanted to see all the power lines in the state of Vermont. I can't download the entire state and then use the filters in JOSM because it's too much data to work with. But if I could download only the ways with the tag "power=line", the amount of data would be very much smaller and they could easily be worked with. But I don't see any way to do this. Thanks.

asked 09 Oct '10, 16:09

OceanVortex's gravatar image

OceanVortex
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accept rate: 0%


Be very careful when working with filtered data in an offline editor because you will not be able to see whether other objects share some of the data you have downloaded. Here are some of the problems that might arise:

  • You have downloaded only power lines. You move a power line according to an aerial image. You accidentally move a power pole into a house, or a river, or a road, which you hadn't downloaded and so you didn't notice.
  • You have downloaded only railways. You simplify a railway line by deleting some of the nodes, unaware that one of the nodes is indeed a level crossing shared by a footway which you haven't downloaded. Your upload will fail.
  • You have downloaded only roads. You move one highway's nodes about to improve the geometry, not seeing that one node was actually also used by an administrative boundary running across the road; your upload will work but you have created an ugly dent in the boundary.

At the very least, when using filtered data, have a fully rendered OSM map displayed in the background so you are alerted to potential trouble spots.

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answered 09 Oct '10, 18:36

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
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accept rate: 23%

edited 11 Oct '10, 08:46

1

Thanks, these are very good caveats to be aware of.

(09 Oct '10, 20:19) OceanVortex
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Does JOSM provide any level of protection against some of these potential problems? If not, maybe something could be implemented.

(30 Dec '11, 10:02) Kozuch

Take a look at XApi. It is an eXtended API that allows you to filter the downloads. You can open the url in josm by selecting File->Open Location...

You can for example use http://www.informationfreeway.org/api/0.6/way[bbox=11.54,48.14,11.543,48.145][power=line].

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answered 09 Oct '10, 17:54

Gnonthgol's gravatar image

Gnonthgol ♦
13.8k16103198
accept rate: 16%

2

Thanks, that's exactly what I needed.

(09 Oct '10, 20:21) OceanVortex

Is XApi still the recommended solution to download only a subset of data from OSM and avoid being overwhelmed, or is there a better way?

(05 Nov '19, 23:44) Shohreh
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@Shohreh: You can export data from Overpass Turbo into JOSM. JOSM also has methods to download from Overpass itself, as well as Sophox. As fas as I can see XAPI is no longer supported by default. I assume Overpass is the preferred method nowadays.

(06 Nov '19, 04:12) escada

Thank you. I'll check if there are any traps/drawbacks when downloading just a subset through Overpass Turbo.

(06 Nov '19, 10:15) Shohreh

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question asked: 09 Oct '10, 16:09

question was seen: 10,949 times

last updated: 06 Nov '19, 10:15

NOTICE: help.openstreetmap.org is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum