[Qgis-user] On the fly projection

[Siki Zoltan]

Dear Richard,

thanks, I've change sqlite db.

regards,
Zoltan

On Sun, 13 Feb 2011, Richard Duivenvoorde wrote:

> Siki Zoltan wrote:
>> I have trouble with on the fly projection from epsg:4326 to epsg:23700.
>> When I create a custom projection and test it in QGIS custom projection
>> window I get the correct values
>> E.g 47d 19d -> 183979.50 646390.96
>> parameters: +proj=somerc +lat_0=47.14439372222222
>> +lon_0=19.04857177777778 +k_0=0.99993 +x_0=650000 +y_0=200000
>> +ellps=GRS67 +towgs84=52.17,-71.82,-14.9,0,0,0,0 +units=m +no_defs
>>
>> But when I have the same point in a shape file and turning on on the fly
>> reprojection with EPSG:23700,
>> I get 646306.05 183949.62, and it is the same if I ommit the towgs84
>> parameters, more than 90 meters difference.
>> Where can I change the projection definition permanently in QGIS?
>> I changed the epsg file of proj but it doesn't help.
>>
>> Trying it on QGIS 1.6 Linux and XP, I get the same result.
>
> Hi,
>
> the projection information / proj4-strings for qgis are stored in srs.db
> (<QGIS>/share/qgis/resources/srs.db in my setup) which is a sqlite
> database (viewable/editable with eg a firefox plugin:
> https://addons.mozilla.org/en-US/firefox/addon/sqlite-manager/)
> You could edit the record there for the epsg:23700 record. But this
> means that with a new install you loose your proj-string edits.
>
> The preferred way is actually to add a 'Custom CRS' (file menu Edit) and
> add your definition of the proj-string and name it 'My23700' crs or
> something like that.
> Then the definition ends up in qgis.db (the user settings sqlite db) in
> your .qgis home. And it will survive new projects and your qgis-updates
> in the future.
>
> Regards,
>
> Richard Duivenvoorde
>