Hi Martin, 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, Eric On Wed, Mar 3, 2021 at 11:00 AM Martin Dobias <wonder...@gmail.com> wrote: > Hi Eric > > On Wed, Mar 3, 2021 at 3:48 PM Eric Younkin - NOAA Federal < > eric.g.youn...@noaa.gov> wrote: > >> Looking for some advice. We have a need to use OpenGL to draw the >> symbology associated with some vector data. All of our code uses OpenGL >> 1.x. I was thinking we could use the QOpenGLWidget and the QgsPluginLayer >> to add our OpenGL rendered symbology to a QgsMapCanvas as a new layer. >> >> Is this possible? Is there an example anyone knows of that is kind of >> similar to this idea? Or is there a better way to approach this problem? >> > > Could you please provide some more details regarding the symbology you > would like to get rendered? A screenshot would help a lot... > > If you plan to use mesh-based weather data, maybe what you are trying to > do is already possible with the mesh layer in QGIS out of the box (e.g. > display of arrows, streamlines, trace animation), or there is only small > amount of extra work do be done in QGIS core to achieve that. > > As for OpenGL approach (it looks like you already have some existing code > you would like to adapt to QGIS)... are you looking just at 2D rendering or > 3D rendering as well? I know some time ago for QGIS 2.x Vincent Mora has > created a plugin layer that used OpenGL to render to offscreen image and > then draw it in map canvas [1] which involved some hacks. With > QOpenGLWidget approach I would be quite cautious as it may not work well, > or have some strange issues on different platforms. For example, I _think_ > the QOpenGLWidget can't be semi-transparent (but I may be wrong), so mixing > its content with the rest of the map could be quite tricky... > > Regards > Martin > > [1] https://github.com/Oslandia/meshlayer > -- 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
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