[GRASS-user] WMS fails on Geosciences Australia downloads

[Richard Chirgwin]

Hamish wrote:
> Richard Chirgwin wrote:
>   
>> I am trying to access layers on the Geosciences Australia
>> OGC Web Map server:
>>     
> http://www.ga.gov.au/wms/getmap?dataset=national&request=getCapabilities
> .....
> Hamish:
>   
>> I'll be kind and say GRASS because /technically/ the other end conforms
>> to the WMS spec. The problem was that the other end does not accept
>> queries in the form of HTTP POST data.
>>     
> [r.in.wms -g flag added to deal with that; this works:]
>   
>> r.in.wms -l -g mapserv="http://www.ga.gov.au/wms/getmap?dataset=national&"
>>
>> # search for Gold:
>> r.in.wms mapserv="http://www.ga.gov.au/wms/getmap?dataset=national&" \
>>   -g layers=au_occdd output=au_gold format=tiff
>>     
> ....
>   
>> ps- sorry if this email is wrapping at about char 90, yahoo as upgraded
>> their system & removed the "wrap at 72" compose setting, I suppose to
>> make things simpler for us.
>>     
> [I hope to get back to using fetchyahoo.pl+cron and a sane client soon]
>
> Richard:
>   
>> I didn't notice the mail wrapping issue ...
>>     
>
> yours is missing newlines- even worse!  :)
> (hint: don't post as HTML/rich formatted)
>
>
>   
>> Thanks for all your efforts. There's still something strange at the
>> Geosciences Australia end; I have repeated your test with the Gold
>> layer (success). But other layers show errors like "wms_roads__0.png
>> not recognised as a supported file format".
>>     
>
> if you look in that file you will see text not an image:
> <?xml version='1.0' encoding="ISO-8859-1" standalone="no" ?>
> <!DOCTYPE ServiceExceptionReport SYSTEM "http://schemas.opengeospatial.net/wms/1.1.1/exception_1_1_1.dtd">
> <ServiceExceptionReport version="1.1.1">
> <ServiceException code="InvalidSRS">
> msWMSLoadGetMapParams(): WMS server error. Invalid SRS given : SRS must be valid for all requested layers.
> </ServiceException>
> </ServiceExceptionReport>
>
>
> be sure to delete those old files from $GISDBASE/wms_downloads/ or they will be cached and it'll try to reuse them. ('r.in.wms -c' helps)
>
>
> 'r.in.wms -l' and  http://www.ga.gov.au/map/broker/wms_info.php state that the roads layer is in EPSG:3112, so you need to provide that on the command line:
>
> # from a latlon/wgs84 location
> g.region n=9S s=46S w=112E e=155E res=0:01 -p
> r.in.wms mapserv="http://www.ga.gov.au/wms/getmap?dataset=national&" \
>   -g layers=roads output=au_roads format=tiff srs=EPSG:3112
>   
Richard:
You're right; so the trick is to be careful!

I hope this is the last maddening issue; working with:
g.region n=33S s=34S w=150 e=151 nsres=00:00:05 ewres=00:00:05
r.in.wms -c mapserv="http://www.ga.gov.au/wms/getmap?dataset=national&" 
-g layers=dem_9sec output=dem_9sec format=png srs=EPSG:3112
(The small region keeps the the tile size down)

I get the 9-second DEM. It looks and displays okay, but the elevation 
data is wild.
r.what -f input=dem_9sec at PERMANENT east_north=150.8177882,-33.785157971
produces:
150.8177882|-33.785157971||31407|

Since I can reasonably assume that the elevation isn't 31,407 metres, 
nor that the elevation in the mountains is lower than near the ocean, 
something's awry with the elevation... I will test it later with TIFF to 
see if that works better on elevation, I'm getting called away at the 
moment...

Richard


>
>
>   
>> So the server would have to be considered "a little flaky" on a good day.
>>     
>
> naw, blame r.in.wms. the server is limited in what it will provide and r.in.wms is not handling the error messages well. (the error can come in the form of a web page, XML, or empty output, and success is a real image, so it is hard to pick how to recognize and pass on the error)
>
>
> devs: One problem is that I don't know how to test for r.in.gdalwarp's exit code. it is called from r.in.wms with eval- the exit code returned is eval's not r.in.gdalwarp's.
>
>
>
>   
>> The tiles download okay - the directory shows files with .wget, .png
>> (or tiff or whatever), .proj4 and .tfw formats, so I guess something is
>> breaking / broken in the files GA is sending.
>>     
>
> no, open the tile in a text editor and see
>
>
>
> with the extra "srs=EPSG:3112" on the command line I could download the roads layer and it looks good.
>
>
>
> Hamish
>
>
>
>       
>
>   
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