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Hi, Is there any restriction on the type of data we can download from the osm (as export option) or cloudmade website or geofabrik website? I have downloaded data of a city but it is not having all the road as it is shown in the live map (osm.org). Can anyone help in this regard? Thanks in advance. |
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The short answer is no - you get the current state of all the current data when you export from OSM. In order to be of more help, we'd need to know what you've downloaded and from where. It's perfectly possible for someone to make available a cut-down subset of OSM data for a particular purpose. Do be aware that data extracts on some external sites my be quite old - the download sites suggested from the "export" function when you try an export a large area are a good starting point: I didn't get current state of data downloaded even from export option at osm.org. I wanted to download the data of the extent http://www.openstreetmap.org/export#map=15/17.4024/78.5370 however what I see in the map is not what I got in the downloaded file.
(04 Dec '13, 12:28)
GoldenCompass
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Can you give an example of something that's on the map but not in the download? It's possible that a road might have been deleted from the data but not yet rerendered and hence still on the map, but I can't see an obvious example from a quick look at the data layer.
(04 Dec '13, 12:38)
SomeoneElse ♦
I am trying to download data for Amberpet, Hyderabad - India area almost the area at zoom level of 15. However many of the small road segments are not getting downloaded. I know that these data (in the map) are there for quite sometime but still why not included in the downloadable file?
(05 Dec '13, 09:52)
GoldenCompass
Can you give an example of a way id that's on the map that's not in the downloaded file? I've just downloaded the area covered by your export link and received a 596226 byte file, with 7519 lines in it. What did you get?
(05 Dec '13, 11:05)
SomeoneElse ♦
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I am getting even less than 1MB of the data for that region (may be a bit different due to screen size). You may see the screenshots: First one is the data directly exported from the osm.org while secondly one shows the data downloaded from the mirror sites recommended by OSM (geofabrik/cloudmade). If direct export we can figure out the outline of the all roads (with the help of points) while many of them are even missing from mirror site data.
(05 Dec '13, 11:18)
GoldenCompass
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You don't say what format you're using. If it's a shapefile, some data is likely to be missing as a result of the conversion to shapefile format. An .osm file will give you the full data, but it's possible that some is being lost in the .osm translator of whatever program you're using (looks like QGIS).
(05 Dec '13, 11:30)
Richard ♦
1st screenshot is of .osm format while 2nd is of shapefile data. So you mean that exported data from osm.org will have all the nodes/ways but while displaying it on any GIS s/w, it is losing some of them!! So if I export the OSM file directly in the database, it will have all the nodes/ways?
(05 Dec '13, 11:37)
GoldenCompass
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(Oversimplifying greatly: ) Shapefiles typically have a limited number of "columns", whereas OpenStreetMap has an unlimited number of freeform "tags". So when you create a shapefile from OSM data, any information that doesn't fit in those columns is lost. Whether you can load an .osm file directly into your GIS program, without any data loss, depends on the setup of your GIS program. You may have to tell it what tags you want to import.
(05 Dec '13, 11:42)
Richard ♦
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