[Qgis-user] styled vector to raster layer

[Andreas Plesch]

Hi Matthias,

sounds like exactly what I need. Unfortunately, QFieldSync depends on
qgis2compat which in turn wants to use the QtTest PyQt module which
apparently I do not have. Ah, my default PyQt4 was compiled and installed
without QtTest, will just need to reinstall. Perhaps of interest that not
all systems come with QtTest by default.

I looked at https://github.com/opengisch/qfieldsync a bit, perhaps I can
extract the relevant parts.

Thanks, I would never have discovered this by myself,

-Andreas





On Wed, May 31, 2017 at 1:25 PM, Matthias Kuhn <matthias at opengis.ch> wrote:

> Hi Andreas,
>
> You can use the QFieldSync plugin which comes with a processing algorithm
> that renders a styled map within a given extent to a raster dataset.
>
> Matthias
>
> On 5/31/17 6:29 PM, Andreas Plesch wrote:
>
> Responding to myself, I found this processing script in the script
> repository:
>
> https://github.com/qgis/QGIS-Processing/blob/master/scripts/
> Create_rasters_from_canvas_for_each_vector_layer_feature_extent.py
>
> It does almost what I had in mind. Its presence indicates that indeed some
> Python scripting is necessary.
>
> I may give it a try. Unlike above, I would probably try to avoid using the
> composer and just go for the straight maprenderer as in the map rendering
> cookbook example: http://docs.qgis.org/2.18/en/docs/pyqgis_developer_
> cookbook/composer.html#simple-rendering
>
> I wonder if it will be necessary to clone the mapcanvas maprendercontext
> to preserve current settings ?
>
> The main idea is to use the rasterized, styled vector layer as a
> georeferenced image outside of QGis.
>
> -Andreas
>
> On Tue, May 30, 2017 at 2:19 PM, Andreas Plesch <
> andreasplesch at netscape.net> wrote:
>
>> I feel I am missing a basic function somewhere to "burn" (in gdal terms)
>> a vector layer as styled by QGIS, for example with labels, to a raster
>> layer (of some resolution).
>>
>> The Rasterize (vector to raster) function is based on gdal_rasterize and
>> does not take into account styling as it focuses on preserving the actual
>> data.
>>
>> The work around I am currently using is to use Project-Save as Image
>> while displaying only the styled vector layer which will generate a correct
>> world file helper, then loading the generated image as raster layer and
>> assigning the correct projection. Finally, I clip the raster with the
>> original extent of the vector layer.
>>
>> This works but is limited as the resolution is constrained by the
>> physical size of the map window and requires the additional house keeping
>> steps.
>>
>> qgis2web or QTiles or OGR2Tiles as plugins do something like this
>> internally but I could not find a plugin which just generates a regular
>> raster layer (say geotiff).
>>
>> I also know I could probably produce a short Python script (perhaps as
>> processing script) to do this but still think I am missing something ?
>>
>> Any help or hint much welcome,
>>
>> Andreas
>>
>>
>
>
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