[gdal-dev] WCS: Bug in WCSDataset110::GetCoverageRequest()

Tue Oct 16 23:01:04 PDT 2018

Odd Ragnar Lydersen kirjoitti 16.10.2018 klo 9.08:
> Thanks for the help.
> It works like it's supposed to now.
>
> If I use it for this other wcs though, I get an error:
>   - URL: "WCS:http://openwms.statkart.no/skwms1/wcs.dtm?VERSION=1.1.1&identifiers=land_utm33_10m"
>   - Error message: ERROR 1: msWCSGetCoverage(): WCS server error. A non-zero RESX/RESY or WIDTH/HEIGHT is required but neither was provided.
> (If I use vesion 2.0.1 then it's fine)
>
> Is it a server error?

It's an error from MapServer

> Is there a way around it, by adding some extra parameters?

This line from the docs is applicable:

NrOffsets: Set to 2 if the server requires that there are only two 
values in the GridOffsets. Use when the server is MapServer or ArcGIS. 
With MapServer use also OffsetsPositive.

also NoGridAxisSwap is needed

So,

gdalinfo -oo OffsetsPositive -oo NrOffsets=2 -oo NoGridAxisSwap 
"WCS:http://openwms.statkart.no/skwms1/wcs.dtm?VERSION=1.1.1&identifiers=land_utm33_10m"

is the correct approach and it does not fail.

Ari

>
>> Odd-Ragnar<
> -----Original Message-----
> From: Ari Jolma <ari.jolma at gmail.com>
> Sent: onsdag 10. oktober 2018 15:02
> To: gdal-dev at lists.osgeo.org
> Subject: Re: [gdal-dev] WCS: Bug in WCSDataset110::GetCoverageRequest()
>
> Hi Odd Ragnar,
>
> Without going very deep into this, I would do (and tried)
>
> gdalinfo "WCS:https://wms.geonorge.no/skwms1/wcs.hoyde-dtm1_32"
>
> This tells me that the preferred version of the service is 2.0.1 and it serves coverage Coverage1. However, if I want to use service version 1.1.1, I do
>
> gdalinfo
> "WCS:https://wms.geonorge.no/skwms1/wcs.hoyde-dtm1_32?version=1.1.1"
>
> This tells me that version is ok but now the coverage name is 1, so
>
> gdalinfo
> "WCS:https://wms.geonorge.no/skwms1/wcs.hoyde-dtm1_32?version=1.1.1&coverage=1"
>
> tells me details about this coverage which seems to be huge. Now that is the src_dataset string to be used in gdal_translate.
>
> Ari
>
>
> Odd Ragnar Lydersen kirjoitti 10.10.2018 klo 14:11:
>> I have investigated some more now, and I've found that the problem is perhaps the way I'm using the data source/service description file.
>>
>> Here is what I do:
>> 1) I open the wcs by providing the coverage I want by using describecoverage in the url:
>> std::string wcsDescribeCoverage =
>> "WCS:https://wms.geonorge.no/skwms1/wcs.hoyde-dtm1_32?SERVICE=WCS&REQU
>> EST=DescribeCoverage&IDENTIFIERS=1&VERSION=1.1.1";
>> GDALDatasetUniquePtr
>> poDS1(GDALDataset::Open(wcsGetCapabilites.c_str(), GDAL_OF_READONLY,
>> pOptionDriverName, pOptionOpenOptions, nullptr));
>>
>> Now I have a valid data set, poDS1.
>> And a service description file has been created in the cache:
>> <WCS_GDAL>
>>     <ServiceURL>https://wms.geonorge.no/skwms1/wcs.hoyde-dtm1_32?</ServiceURL>
>>     <Version>1.1.1</Version>
>>     <CoverageName>1</CoverageName>
>>     <Parameters>SERVICE=WCS&REQUEST=DescribeCoverage</Parameters>
>>     <TIMEOUT>300</TIMEOUT>
>> </WCS_GDAL>
>>
>> 2) Then I run GDALTranslate(), with a valid argList
>> GDALTranslateOptions *TranslateOptions =
>> GDALTranslateOptionsNew(argList, NULL); GDALDatasetH hOutputDataset =
>> GDALTranslate("./test.xyz", GDALDataset::ToHandle(poDS2.get()),
>> TranslateOptions, NULL);
>>
>> During the GDALTranslate() I find that in wcsdataset110.cpp, WCSDataset110::GetCoverageRequest(), line 227:
>> - After the GetCoverage request have been constructed, the parameters from the service description file is used to overwrite the created request, making it a DescribeCoverage request as stated in the file.
>> - And DescribeCoverage don't want IDENTIFIER=someId, but
>> IDENTIFIERS=someId
>>
>> Then, my question is, how am I supposed to do this, to make it right?
>>
>>> Odd-Ragnar<
>> -----Original Message-----
>> From: Peter Baumann <p.baumann at jacobs-university.de>
>> Sent: tirsdag 9. oktober 2018 15:10
>> To: jratike80 <jukka.rahkonen at maanmittauslaitos.fi>;
>> gdal-dev at lists.osgeo.org
>> Subject: Re: [gdal-dev] WCS: Bug in
>> WCSDataset110::GetCoverageRequest()
>>
>>
>>
>> On 09.10.2018 15:06, jratike80 wrote:
>>> Odd Ragnar Lydersen wrote
>>>> I think there is a bug in WCSDataset110::GetCoverageRequest()
>>>> At line 178: "&VERSION=%s&REQUEST=GetCoverage&IDENTIFIER=%s"
>>>> Should be : "&VERSION=%s&REQUEST=GetCoverage&IDENTIFIERS=%s"
>>>>
>>>> At least that fixes my problem, and I can get one step further in my
>>>> effort to use the wcs driver, using C++ API, on Windows.
>>>>
>>>>> Odd-Ragnar<
>>> Hi,
>>>
>>> I believe that GDAL is right and the WCS server that you are using is wrong.
>>> By reading the standard
>>> https://portal.opengeospatial.org/files/07-067r5
>>> the name of the parameter in GetCoverage is "identifier". However,
>>> for making it a bit more complicated for the developers it is called
>>> "identifiers" in DescribeCoverage.
>> well, design by committee effect if you will: DescribeCoverage can have more than one parameters, so it was requested to change to plural in the course of the adoption discussions.
>> whatever way you do it, you will do it wrong ;-)
>>
>> cheers,
>> Peter (WCS/CIS spec editor)
>>
>>
>>> "This single ―identifiers parameter shall correspond to the
>>> repeatable ―identifier parameter in the UML model."
>>>
>>> -Jukka Rahkonen-
>>>
>>>
>>>
>>>
>>> --
>>> Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html
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>> --
>> Dr. Peter Baumann
>>    - Professor of Computer Science, Jacobs University Bremen
>>      www.faculty.jacobs-university.de/pbaumann
>>      mail: p.baumann at jacobs-university.de
>>      tel: +49-421-200-3178, fax: +49-421-200-493178
>>    - Executive Director, rasdaman GmbH Bremen (HRB 26793)
>>      www.rasdaman.com, mail: baumann at rasdaman.com
>>      tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
>> "Si forte in alienas manus oberraverit hec peregrina epistola incertis
>> ventis dimissa, sed Deo commendata, precamur ut ei reddatur cui soli
>> destinata, nec preripiat quisquam non sibi parata." (mail disclaimer,
>> AD 1083)
>>
>>
>>
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