[QGIS-Developer] PYQGIS - OpenGL in QgsPluginLayer

[Eric Younkin - NOAA Federal]

All,

This is very useful, thanks.  The S57 driver does appear to give the layers
by names that I recognize:

INFO: Open of `C:\collab\dasktest\data_dir\13238_FFF.000'
      using driver `S57' successful.
1: DSID (None)
2: LNDARE
3: LNDELV
4: SBDARE
5: UWTROC (Point)

I've found the QML format spec here
<https://docs.qgis.org/3.16/en/docs/user_manual/appendices/qgis_file_formats.html>,
but is there any guidance on starting from scratch?  Thanks again for all
the help.

Eric


On Wed, Mar 3, 2021 at 12:38 PM Martin Dobias <wonder.sk at gmail.com> wrote:

> Hi Eric
>
> On Wed, Mar 3, 2021 at 5:48 PM Eric Younkin - NOAA Federal <
> eric.g.younkin at noaa.gov> wrote:
>
>> Thanks for the quick reply.  This is for NOAA nautical chart symbology,
>> following the s57/s52 spec.  You can see the symbology in the online viewer
>> here <https://www.nauticalcharts.noaa.gov/ENCOnline/enconline.html>.  It
>> is basically a very complex spec that we generated for display in a
>> wxPython widget a long time ago using GDAL 1.x commands.  S57 is already an
>> existing OGR driver, although I do not know what exactly that driver does.
>> I do know that it does not somehow generate the symbology of the data for
>> you to then render.
>>
>> The vector data would be a combination of area/line/point features, and I
>> don't think it would be a fit for the Mesh layer.
>>
>> We'd like to make this symbology available in QGIS, so that users can
>> drag in a s57 file and view the chart.  You can use one of our WMS
>> services, but having the file support would be useful.  Ideally in a plugin
>> layer, so that I can also use it in our other apps that use PYQGIS QgsMapCanvas
>> widgets.
>>
>
> Thanks for more background. In this case the mesh layer indeed is not
> useful. I have not worked with S57 before, but if there is OGR driver
> available, it should be relatively easy to load and style the data without
> a plugin layer. You do not need to rely on styling provided by OGR (if
> provided at all). It looks like you only need to load the data as a bunch
> of vector layers using OGR (one for each object type) and then apply
> styling to those individual layers. Styling of vector layers in QGIS is
> fairly strong, with features like rule-based rendering, data-defined
> properties and geometry generators you can handle even very complex styles.
> After preparing individual styles for vector layers, you can save them to
> .qml files, and then your plugin would have just a simple task of taking
> the input file(s), load layers and apply saved styles.
>
> I would resort to writing a custom plugin layer only when when all other
> options fail - it is more complex, and generally the user experience is not
> great.
>
> Regards
> Martin
>
>

-- 
Eric Younkin
Physical Scientist
NOAA OCS, Hydrographic Systems and Technology Branch
1315 East-West Highway
N/CS11, Room 6604
Silver Spring, MD 20910
Office: 240-847-8208
Cell: 828-331-8197
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20210303/b16f603c/attachment.html>