[QGIS-Developer] Setting a custom CRS for the map canvas

[Tim Sutton]

Thank you very much Matthias, that fixed it.

Updated my Gist accordingly here:
https://gist.github.com/timlinux/1057c2c6b5ebda6ed2b5aa8c5aa21372

Regards

Tim

On Tue, Nov 17, 2020 at 7:57 AM Matthias Kuhn <matthias at opengis.ch> wrote:

> Hi Tim,
>
> Does it help if you directly call `mapCanvas.setDestinationCrs()` instead
> of setting the crs on `mapSettings()`?
>
> The returned mapSettings object is not meant to be modified.
>
> Matthias
>
>
> On Tue, Nov 17, 2020 at 12:58 AM Tim Sutton <tim at kartoza.com> wrote:
>
>> Hi Folks
>>
>> I am trying to update a 2.x snippet I have which iteratively sets the CRS
>> with sequentially higher LO values:
>>
>> https://gist.github.com/timlinux/1057c2c6b5ebda6ed2b5aa8c5aa21372
>>
>> # Uses a trick from Alexander Neto: "I created a orthographic projection
>> with lisbon longitude, but with a south hemisphere latitude
>> # That way kinda looks 3d"
>> # This will make the QGIS use a world projection and then move the center
>> # of the CRS sequentially to create a spinning globe effect
>> import time
>> from subprocess import call
>> longitude_increments = 5
>> image_counter = 1
>> for i in range(-180, 180, longitude_increments):
>>   definition = (
>>   '+proj=ortho +lat_0=-20 +lon_0=%i +x_0=0 +y_0=0 +R=6371000 +units=m
>> +no_defs +type=crs' % i)
>>   crs = QgsCoordinateReferenceSystem()
>>   crs.createFromProj(definition)
>>   iface.mapCanvas().mapSettings().setDestinationCrs(crs)
>>   #iface.mapCanvas().setMapUnits(0)
>>   iface.mapCanvas().refresh()
>>   iface.mapCanvas().saveAsImage(
>>     '/tmp/globe-%03d.png' % image_counter)
>>   image_counter += 1
>>   print (definition)
>>   time.sleep(1)
>> # Now generate the GIF. If this fails try run the call from the command
>> line
>> # and check the path to convert (provided by ImageMagick) is correct...
>> call('/usr/bin/convert -delay 35 -loop 0 /tmp/globe-*.png /tmp/globe.gif')
>>
>> The  example python above using Orthographc North will hopefully make a
>> more pleasing looking spinny globe. However, in QGIS 3.x the code runs
>> but if I inspect the mapcanvas CRS after setting the new CRS, it still
>> shows the old CRS. Can anyone see what I am missing here?
>>
>> Thanks!
>>
>> Regards
>>
>> Tim
>>
>> --
>>
>> ------------------------------------------------------------------------------------------
>>
>> Tim Sutton
>> Visit http://kartoza.com to find out about open source:
>>  * Desktop GIS programming services
>>  * Geospatial web development
>> * GIS Training
>> * Consulting Services
>> Tim is a member of the QGIS Project Steering Committee
>>
>> -------------------------------------------------------------------------------------------
>> _______________________________________________
>> QGIS-Developer mailing list
>> QGIS-Developer at lists.osgeo.org
>> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
>> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
>
>

-- 
------------------------------------------------------------------------------------------
​

Tim Sutton
Visit http://kartoza.com to find out about open source:
 * Desktop GIS programming services
 * Geospatial web development
* GIS Training
* Consulting Services
Tim is a member of the QGIS Project Steering Committee
-------------------------------------------------------------------------------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20201118/fba79e74/attachment.html>