Hi,
I’m using the gridsets with EPSG:27700 - British National Grid.
Out of curiosity I tried the “compute from maximum extent of CRS” button. It came up with some numbers that seem a little off.
MimX: 1,346.748175220855
MimY: 7,097.996956234318
MaxX: 671,066.5126380573
MaxY: 1,230,202.1293903186
The correct numbers for OSGB are:
0,0 to 700000, 1300000
So its close, but slightly off. Should I report this as a bug?
Jonathan
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On Fri, Dec 14, 2012 at 5:29 PM, Jonathan Moules <jonathanmoules@anonymised.com…4942…> wrote:
Hi,
I’m using the gridsets with EPSG:27700 - British National Grid.
Out of curiosity I tried the “compute from maximum extent of CRS” button. It came up with some numbers that seem a little off.
MimX: 1,346.748175220855
MimY: 7,097.996956234318
MaxX: 671,066.5126380573
MaxY: 1,230,202.1293903186
The correct numbers for OSGB are:
0,0 to 700000, 1300000
So its close, but slightly off. Should I report this as a bug?
Not to GeoServer, that data is coming from the official EPSG database:
http://www.epsg.org/ (we are using a slightly older version than the latest)
Cheers
Andrea
–
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it
So does that mean the EPSG is wrong or the calculation is wrong?
It’s not much of an issue - I can manually enter it, but it may be wrong for other projections too.
On 14 December 2012 16:40, Andrea Aime <andrea.aime@anonymised.com1107…> wrote:
On Fri, Dec 14, 2012 at 5:29 PM, Jonathan Moules <jonathanmoules@anonymised.com> wrote:
Hi,
I’m using the gridsets with EPSG:27700 - British National Grid.
Out of curiosity I tried the “compute from maximum extent of CRS” button. It came up with some numbers that seem a little off.
MimX: 1,346.748175220855
MimY: 7,097.996956234318
MaxX: 671,066.5126380573
MaxY: 1,230,202.1293903186
The correct numbers for OSGB are:
0,0 to 700000, 1300000
So its close, but slightly off. Should I report this as a bug?
Not to GeoServer, that data is coming from the official EPSG database:
http://www.epsg.org/ (we are using a slightly older version than the latest)
Cheers
Andrea
–
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it
This transmission is intended for the named addressee(s) only and may contain sensitive or protectively marked material up to RESTRICTED and should be handled accordingly. Unless you are the named addressee (or authorised to receive it for the addressee) you may not copy or use it, or disclose it to anyone else. If you have received this transmission in error please notify the sender immediately. All email traffic sent to or from us, including without limitation all GCSX traffic, may be subject to recording and/or monitoring in accordance with relevant legislation.
On Fri, Dec 14, 2012 at 6:06 PM, Jonathan Moules <jonathanmoules@anonymised.com…4942…> wrote:
So does that mean the EPSG is wrong or the calculation is wrong?
Probably neither. The EPSG database reports the bounds of a coordinate reference system
as its “area of validity” in geographic coordinates, and I believe it’s done mostly to locate
where in the world the CRS is meant to be used as opposed to provide a very precise location
of its bounds.
For 27700 we get this bounds out of the EPSG database:
60°50’24,0"N, 07°33’36,0"W - 49°57’36,0"N, 01°46’48,0"E
We then reproject them into 27700 (and mind, we don’t have the ntv2 grid shift files to improve
the datum shift calculations) and that’s what we provide the user.
They might not be completely accurate, but that’s all we have
Cheers
Andrea
–
Ing. Andrea Aime
@geowolf
Technical Lead
GeoSolutions S.A.S.
Via Poggio alle Viti 1187
55054 Massarosa (LU)
Italy
phone: +39 0584 962313
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it