[Qgis-user] downloading a wms geoservice from QGis

Mon Nov 7 13:33:57 PST 2016

Yes, I did set a resolution as you explained:

[image: Imagem inline 1]

I could finally get a file but the resolution is too poor (all pixelized)>
I tried with none compression but still not good. I guess the horizontal
and vertical resolutions are too low, but don´t really understand the
parameter to be sure what would be a good value. Any sugestions?

2016-11-07 19:27 GMT-02:00 Andreas Neumann <a.neumann at carto.net>:

> 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>:
>
>> 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>:
>>
>>> 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 downloading and uploading and then end up with an outdated image.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>:
>>>
>>>> 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
>>>>
>>>>
>>>>
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>>>
>>> --
>>> *Juliana Mori*
>>> www.julianamori.com
>>> +55 11 999653145
>>>
>>> --
>> *Juliana Mori*
>> www.julianamori.com
>> +55 11 999653145
>>
> --
> *Juliana Mori*
> www.julianamori.com
> +55 11 999653145
>
>

-- 
*Juliana Mori*
www.julianamori.com
+55 11 999653145
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