[Qgis-user] downloading a wms geoservice from QGis

Andreas Neumann a.neumann at carto.net
Mon Nov 7 13:27:08 PST 2016


So - have you tried setting a resolution and extent? The resolution 
input fields need to have values. Empty fields don't work. And no - QGIS 
can't autodetect it. It does not know the native resolution of WMS services.

Andreas


Am 07.11.2016 um 22:23 schrieb Juliana Mori:
> sorry, I hit enter before finishing the email... Again:
>
> Hi Andreas,
>
> for sure it would be much better to use the webservice directly but 
> I´m already investigating with CARTO and it seems there´s no WMS 
> support - if I have any update on this, I´ll share with you.
>
> EPSG:4326 would be perfect for me, even though I know the original 
> file is in Magna Sirgas (EPSG:4686). So, if I understood right, I need 
> to specify a resolution in decimal degrees, right?
>
> I´m saving a raster image with only 3 color values (assigned by its 
> column "dn" which indicates if the pixels correspond to forest, no 
> forest or no information). Sorry, I don´t know to say if it´s orthoimage.
> I´ve already polygonized the other tiff files I had from this series 
> (but were not from WMS) and the results were meaningful, probably 
> because there´re only this 3 colors.
>
>
>
> 2016-11-07 19:18 GMT-02:00 Juliana Mori <julmori at gmail.com 
> <mailto:julmori at gmail.com>>:
>
>     Hi Andreas,
>
>     for sure it would be much better to use the webservice directly
>     but I´m already investigating with CARTO and it seems there´s no
>     WMS support - if I have any update on this, I´ll share with you.
>
>     EPSG:4326 would be perfect for me, even though I know the original
>     file is in Magna Sirgas (EPSG:4686).
>
>
>
>     2016-11-07 19:15 GMT-02:00 Andreas Neumann <a.neumann at carto.net
>     <mailto:a.neumann at carto.net>>:
>
>         Hi Juliana,
>
>         First, I would investigate with Carto, if you really cannot
>         embed a WMS. It would be much better to use the webservice
>         directly rather than downloading and uploading and then end up
>         with an outdated image.
>
>         If that does not work, you need to set a meaningful
>         resolution. As we can see in your screenshot the resolution
>         text input fields are empty. Also check if the projection is
>         correct. Do you really want to save in EPSG:4326 or rather in
>         a meter based system?
>
>         What kind of data are you saving? Orthoimages or maps with few
>         colors or black and white? If it is orthoimages, I would use
>         JPEG compression in the Geotiff, otherwise probably deflate/LZW.
>
>         Then you have to find a meaningful resolution. If you really
>         want to save in EPSG:4326, you have to specify a resolution in
>         decimal degrees. Try with larger values first, such as 0.05
>         and then, if it is too coarse go to smaller values.
>
>         About polygonizing raster to vector: this really depends on
>         the content - and I kind of doubt it if you really get
>         meaningful results. Maybe it works with few colors and
>         homogeneous areas. It certainly would not work well for aerial
>         images.
>
>         Hope it helps,
>         Andreas
>
>         Am 07.11.2016 um 22:05 schrieb Juliana Mori:
>>         Hi Andreas,
>>
>>         thanks for your reply.
>>
>>         I chose layer extent for extensions and current layer for
>>         resolution but still doesn´t work.
>>
>>
>>
>>         Should I do this in a different way?
>>
>>         About the bigger question, no, CARTO doesn´t allow uploading
>>         geotiffs. What I´ve done so far is polygonizing the rasters
>>         in QGis and uploading the converted shapefile to CARTO. As
>>         you said WMS can´t be converted into shape, I´m not sure this
>>         is going to work at all... won´t I be able to polygonize a
>>         raster downloaded from a WMS server?
>>
>>         All the best, Juliana.
>>
>>
>>
>>
>>
>>         2016-11-07 18:44 GMT-02:00 Andreas Neumann
>>         <a.neumann at carto.net <mailto:a.neumann at carto.net>>:
>>
>>             Hi Juliana,
>>
>>             "Save AS" as a WMS should work fine - but you need to
>>             specify a useful extent and resolution (in map units of
>>             your projection). Otherwise it probably fails.
>>
>>             I just tested it and it works fine.
>>
>>             The bigger question is: will CARTO allow to upload larger
>>             Geotiff files? Did you check that?
>>
>>             Note that WMS are always raster. You can't convert it
>>             into a shp file.
>>
>>             Andreas
>>
>>
>>             Am 07.11.2016 um 21:27 schrieb Juliana Mori:
>>>             Hello,
>>>
>>>             I have loaded a wms server to QGis, which is a raster
>>>             format. As I need to use this in an external aplication
>>>             (CARTO) which does not support wms, I´m trying to export
>>>             the server loaded into QGIS through "save as"
>>>             funcionality. But it´s not working.
>>>
>>>             Do you know how I can export the wms loaded to a file
>>>             (raster or shp)?
>>>
>>>             Thanks a lot, Juliana.
>>>
>>>
>>>             ps:: I´m working with QGis Essen, 2.14.3
>>>
>>>             -- 
>>>             *Juliana Mori*
>>>             www.julianamori.com <http://www.julianamori.com>
>>>
>>>
>>>
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>>         -- 
>>         *Juliana Mori*
>>         www.julianamori.com <http://www.julianamori.com>
>>         +55 11 999653145 <tel:%2B55%2011%20999653145>
>
>     -- 
>     *Juliana Mori*
>     www.julianamori.com <http://www.julianamori.com>
>     +55 11 999653145 <tel:%2B55%2011%20999653145>
>
> -- 
> *Juliana Mori*
> www.julianamori.com <http://www.julianamori.com>
> +55 11 999653145
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