[Qgis-developer] Openlayers plugin issue

John C. Tull jctull at gmail.com
Thu Feb 18 13:00:33 EST 2010

Hi Mathias,

On Feb 18, 2010, at 1:20 AM, Mathias Walker wrote:

> Hi John
>> I was testing the new openlayers pre-release plugin. One issue I have is a
>> scaling mismatch with my vector layers and the openlayers rendered output.
>> I have a county layer in utm zone 11 (epsg 26911) that is not lining up
>> with the openlayers map. I tried physical and roads layers from Google
>> Maps. I did select the 100006 CRS and enabled OTF transformations for
>> vector layers.
> I tested your vector data both as shapefile and from postgis and the borders 
> lined up nicely with Google Maps on my QGIS build.
> The custom SRS should have the following Proj4 config:
> +proj=merc +lon_0=0 +lat_ts=0 +x_0=0 +y_0=0 +a=6378137 +b=6378137 +units=m 
> +no_defs

This is the SRS setting I have been using.

> Usage note: The data is only aligned for integer values on the zoom level 
> slider.

I tried adjusting zoom levels to whole integers to no avail.

> Could you send me a screenshot of your QGIS map?

I've attached two screenshots (not on list) at different zoom levels. You can see the mismatch where the vector is larger than the actual county boundary, but scales differently at different zoom levels.

>> I don't know if the plugin
>> will support rendering for map composer output, but a quick test did not
>> render the openmap layer to either pdf or a png image output file. The
>> openmap layer did render in the composer itself when I refreshed the
>> cache.
> The map composer is not supported at the moment. There are still a lot of open 
> questions regarding fixed zoom levels combined with resolution scaling and user 
> defined viewports.

FWIW, I'm using qgis built from trunk. I also have qt-4.6.1 installed. This is an OS X platform as well.

Good to know. Thanks,

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