[GRASS-user] Very high resolution topographic map of Europe: need help and advices: UPDATE

Sun Sep 13 11:50:20 EDT 2009

There is some very good hydrodata here:

http://ccm.jrc.ec.europa.eu/php/index.php?action=view&id=24#

Two drawbacks:
- non-commercial use only (see license text)
- comes as ArcGIS Geodatabase file (yuck!)

Version 1 used to be shapefiles, maybe it's still available.

Ben

Felix Schalck wrote:
> Dear All-who-may-be-intersted,
> 
> First, I'd like to apologize for the delay: lots of stuff prevented me
> from working on the map. I've got some spared time now, and the map
> isn't finished yet - so I'm back into buisiness!
> Secondly, I'd like to thank you Markus, for the great script you sent
> me: it worked withouth a hitch, and I have now a single big shapefile
> to work on. And sorry for the last message: it was a misclick.
> 
> Then comes the map: basically, even though the last replies provided
> my with some valuable advices, I'm still stuck with bathymetry -
> rivers and coastlines.
> 
> 1. For the bathymetry, I finally took ETOPO1 data, which gives me
> another nice raster, although of much lower resolution (1' compared to
> the 3" topographic raster from SRTM DEM). So the plan is to cut off
> all the land data from the ETOPO1 raster along the coastlines, to keep
> only the sea aeras and than paste this reduced raster onto the main
> SRTM topographic raster of greater resolution. Can this step be
> automated ? (eg: is there a tool to do the job ?) Of course, should
> raster-merge be to complicated, there is always the other option,
> which is to export pngs first, and paste the pngs together; but in
> both cases, the bathymetric raster has to be cut.
> 
> 2. Rivers and coastlines are a real pain.
> a. I could import a big pasted SWBD shapefile thanks to Markus script,
> but the cleaning process of the import command takes days, and  gets
> somehow stuck within the brigdge removing phase. Result is an
> uncomplete vector map, lacking centroids, which can't be further
> processed by v.generalize for smoothing (the command dies saying there
> is an error in input data), but can be displayed with v.display.
> Another problem are all the square borders left around former SWBD
> tiles in water aeras; can they be removed ? Or do I have to manually
> edit the (huge) vector map ?
> 
> b. Then come the rivers: the (somehow corrupted) SWBD vector map shows
> only coastlines, smaller closed waterbodies and - although only
> partially - larger rivers. I somehow have to complete the river data,
> and try following methods:
> -r.watershed command in grass, to compute the rivers from DEM data.
> This command just dies during the memory allocation process (KILL
> signal) because the map is too huge for my system. I tried with
> differend -m parameters, but the command always askes for up to 10gb
> virtual memory the kernel won't be able to provide. I guess I would
> have to work on smaller pieces of the map, set with g.region, and
> paste the results together, but this is another time consuming option.
> -VMAP0 data import works, but the result is quite disappointing. The
> secondary rivers network seems quite good, but this datased is unable
> to fix the uncomplete major rivers from the SWBD dataset. For an
> instance, by showing both layers (SWBD + VMAP0) on the monitor, I get
> all smaller rivers flowing into the rhine, while the rhine itself
> remains divided into several un-joined segments.
> -OSM(openstreetmap) data is a bit confusing. First it is divided along
> countries, so you have to dowload and paste lots of different files.
> Than the" Waterway" shapefile is quite poor. And finally the "natural"
> shapefile comes with nice river data, but also a lot of confusing
> data, like forest aeras. This need some sort of filtering, but I don't
> know at all how to do this.
> 
> c. Of course, if someone knows better river datasets (scale approching
> 3", complete, easy to use), I would be happy to try them.
> 
> Voila. Even though a lot more problems arise during each step
> (resolution has become another one, for an instance), I hope this
> project will see an end soon.
> Thanks for your help and your patience,
> 
> Felix
> 
> 2009/8/17 Markus Neteler <neteler at osgeo.org>:
>> Hi Felix,
>>
>> On Sun, Aug 16, 2009 at 7:37 PM, Felix Schalck<felix.schalck at gmail.com> wrote:
>> ...
>>> a - Importing the vectors from SWBD is no problem, tough It would be
>>> nice to have the 200+ NASA shapefiles merged BEFORE importing a new
>>> layer in GRASS. Is this possible with ogr2ogr ?
>> Merge of two SHAPE files 'file1.shp' and 'file2.shp' into a new file
>> 'file_merged.shp' is performed like this:
>>
>> # note order "out", then "in":
>> ogr2ogr file_merged.shp file1.shp
>> ogr2ogr -update -append file_merged.shp file2.shp -nln file_merged file2
>>
>> The second command is opening file_merged.shp in update mode, and
>> trying to find existing layers and append the features being copied.
>> The -nln option sets the name of the layer to be copied to.
>>
>> Attached a script to do as many as you want.
>>
>>> b - The big problem are coastlines and waterbodies (+main rivers):
>>> somehow I have to show them on the topographic map, which gdalwarp has
>>> filled out with -32768 values in nodata-waterzones. So either I cut
>>> waterbodies out of the topographic raster along the vectors, or I
>>> somehow have GRASS compute me all waterbodies from the vector layer,
>>> fill them with a nice blue and create a raster which can be pasted
>>> over the topographic raster to get the final map.  It seems doable
>>> with mapcalc, but frankly, I do not know at all how to proceed. Any
>>> help here would be greatly appreciated.
>> Not sure, but set -32768 to NULL (no data) with r.null?
>> Then use r.colors (nv to set color for NULL):
>> http://grass.osgeo.org/grass64/manuals/html64_user/r.colors.html
>>
>> cheers
>> Markus
>>
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> 

-- 
Benjamin Ducke
Senior Applications Support and Development Officer

Oxford Archaeological Unit Limited
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benjamin.ducke at oxfordarch.co.uk

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