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(Please excuse my poor English)

Hi, I am a newbie for Open Street Map.

Currently I'm doing a 3D map project using Aster 1 arcsecond GDEM data. However I found Aster GDEM data have some errors. Most significant error is that Aster GDEM data do not exclude water area(sea, river, lake) data sufficiently.

To correct the error, I sought a land/water mask, but could not found sufficient one having sufficient resolution. So I want to make a land/water mask using OSM coastline data, having sufficient resolution matching for Aster GDEM. But I don't know how.

Would you please let me know how to get land/water mask using OSM coastline data, and how to include other water area(river, lake) data to the land/water mask? Of course, other ideas for correcting the Aster GDEM error will be welcomed.

asked 12 May '15, 08:13

pdh0710's gravatar image

pdh0710
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edited 12 May '15, 08:19


You can use the OSM-based shape files on http://www.openstreetmapdata.com/ - but note that using these files to correct your ASTER dataset will likely have license implications for your resulting data, i.e. it will likely be an OSM-derived database which you then have to license under ODbL 1.0.

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answered 12 May '15, 09:08

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
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accept rate: 23%

Thank you for your reply. I found this.

http://openstreetmapdata.com/data/water-polygons

.......

This dataset only contains bodies of water bordered by ways tagged natural=coastline, it does not contain lakes, reservoirs, etc. tagged with natural=water etc.

Still I don't know below, cause I'm a newbie for OSM. Please let me know more detail.

  1. How I can get a shapefile tagged with natural=water from OSM map data. I want the shapefile includes lake and river data.
  2. How I can get a land/water mask file from the shapefile. the mask file is normally black and white image file.
  3. I will open and share the mask file and corrected Aster GDEM files. Is there any license problem?
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answered 12 May '15, 10:11

pdh0710's gravatar image

pdh0710
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accept rate: 0%

edited 12 May '15, 10:13

Short answer:the coastline you already found it at openstreetmapdata.com.

For lakes, you need openstreetmap data from planet.openstreetmap.org, then look on the wiki.openstreetmap.org for osmfilter.

The other tools you need are ogr2ogr to make shapefiles, and gdal to process the DEM and with resulting shapes, mainly http://www.gdal.org/gdal_rasterize.html.

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answered 12 May '15, 13:18

yvecai's gravatar image

yvecai
1.5k1226
accept rate: 9%

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question asked: 12 May '15, 08:13

question was seen: 3,696 times

last updated: 12 May '15, 13:18

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