[Qgis-user] Bugs

Thu Jul 7 07:10:41 PDT 2011

Hi Andreas, Nathan
        Thanks for the prompt Replies.

> the infrastructure was just changed recently. Did you try on 
http://hub.qgis.org/ - personally I don't know how the accounts are 
handled. The old accounts from trac.osgeo.org were migrated.

This in turn points to the same bugs page. It allows "sign in", but 
there's no "register" button that I can see.

>  Personally, I would really stay away from proprietary formats like ecw 
and mrsid.

In principle I agree, but this is one of the few formats that's supported 
across all our applications internally (the other being JP2000), so it's 
what we've put our data into. We can easily convert the data into pretty 
much any raster format at any time as it's almost all sourced from 
Ordnance Survey TIF's, but we'd prefer not to have multiple versions of 
each raster.
JP2000 seems to be a fairly open standard (it's ISO defined), even if it 
doesn't have much uptake.

I've found a smaller ECW file - 27MB. QGIS hangs for a little over a 
minute when loading this. Extrapolating that up to the 4GB file gives 
2.5hrs to load it! QGIS is also using an absurd amount of RAM (~700MB) 
just to display this single layer. ArcMap tells me this file is 260.35 MB 
uncompressed.

However, following Nathan's suggestion, I have disabled the "Contrast 
Enhancement", and it is now loading all of the aforementioned rasters just 
fine. It's also not using absurd amounts of RAM. I'd humbly suggest making 
this the default.

>  Did you set the projection of your QGIS project? It sounds like this is 
 set to WGS84/degrees. Try to set it to your british national grid and it 
 will probably work fine.

Nope. I'm lazy and used to applications automatically detecting the 
projection of the first layer added and using that for the project (aka 
ArcGIS) ;-) . After some fiddling I found 27700 and it's now correctly 
showing km. But it would be nice if it picked up the projection from the 
first dataset, you can always change it later.

> This is because you probably enabled the "Copyright plugin", which is 
not enabled by default, I think.

I haven't changed any of the plugins (or indeed, any settings whatsoever), 
they're all on default. I suspected it was for showing your own copyright, 
but couldn't see it in the options page. Even now that I know where it is 
(plugins), there's no obvious way to change the text, only enable/disable 
it via "manage plugins". Not that this is important to me, it's just weird 
having someone else's copyright on my map by default.

Thanks again,

Jonathan

From:   Andreas Neumann <a.neumann at carto.net>
To:     <qgis-user at lists.osgeo.org>
Date:   07/07/2011 14:15
Subject:        Re: [Qgis-user] Bugs
Sent by:        qgis-user-bounces at lists.osgeo.org

 Hi Jonathan,

 I can only partially answer your questions/remarks.

>  A few bugs with QGIS 1.7.0. Unfortunately there's no obvious way to
> actually create an account or report bugs on your bug tracker so I'm
> forced to post them here.

 the infrastructure was just changed recently. Did you try on 
 http://hub.qgis.org/ - personally I don't know how the accounts are 
 handled. The old accounts from trac.osgeo.org were migrated.

> 1) I have a ~600MB raster in JP2000 format (*.jp2). QGIS doesn't seem
> to be able to load this, at least not in a timely manner. It spent at
> least 5 mins sitting there eating 100% CPU and using quite a bit of
> RAM.
> I also have a ~4GB ECW file which similar things happen with. Both
> files are projected (OSGB - 27700) and I'm fairly sure they have
> pyramids.
>
> MapInfo, ArcGIS, MapModeller (all proprietary), and MapWindow (Open
> Source) are all capable of displaying both images in fractions of a
> second.

 There has been a lot of mail recently about the problems with ecw.

 Personally, I would really stay away from proprietary formats like ecw 
 and mrsid. You will never know when those companies changed their 
 policies and if they care about compatibility with OS GIS. I personally 
 use TIFF files (bigtiff files are more or less unlimited in size), and 
 you can choose between different compressions in the tiff, like jpeg, 
 deflate, zip, packbits, etc. These files usually work fine. I never had 
 any issues. Back 2-3 years I also experimented with ecw and always ran 
 into issues with software upgrades.

 This doesn't mean that the bug should not be fixed, but it is a 
 recommendation about storing your data.

> 2) I load a shapefile that's projected in British National Grid into
> QGIS. The built in QGIS scale shows "degrees" rather than "metres" as
> the measurement unit despite showing "0" to "30,000" numerically (so
> it is showing metres, it's just incorrectly saying "degrees". This is
> to a new map that has no other layers added.

 Did you set the projection of your QGIS project? It sounds like this is 
 set to WGS84/degrees. Try to set it to your british national grid and it 
 will probably work fine.

> 3) Why is there a "(c) QGIS 2011" in the bottom right of the map
> viewer? 99% + of other programs use the Help->About page for that.

 This is because you probably enabled the "Copyright plugin", which is 
 not enabled by default, I think. You can easily disable it in the 
 plugins manager. The goal of the copyright plugin is not showing the 
 QGIS copyright, but your own copyright (e.g. your company). You can 
 easily configure it to show your own copyright, or better disable it 
 alltogether. For configuration look into the Plugins toolbar and the 
 button with the copyright symbol.

 Hope this helps,
 Andreas

 --
 Andreas Neumann
 Böschacherstrasse 10A
 8624 Grüt (Gossau ZH)
 Switzerland
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