[Geoserver-users] Projection centered on the Pacific Ocean

GeoServer GeoServer User
1

Good afternoon

I need to display some maps which are centered on the Pacific Ocean. After
having spend some times, looking at the different SRS available in
GeoServer, i run a bunch of test with the EPSG=3349.
This is the type of map, i obtain:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:3349
It is effectively centered on the Pacific ocean but, many polygons are not
correctly displayed.

Normal view with EPSG:4326:

http://www.fao.org/figis/geoserver/wms?bbox=-198.0,-98.68118000000004,198.0,92.30478000000085&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:4326

Is it a bug of GeoServer or did I make some mistakes defining the parameters
of my map?Is it the correct SRS with the right bounding box?

My data is extracted from an Oracle DB and i am using GeoServer 1.6.5. I
tried with the 1.7.0-RC1-pre version, it have obtained a white page.

Thanks for helping me.

Sylvain
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View this message in context: http://www.nabble.com/Projection-centered-on-the-Pacific-Ocean-tp18983741p18983741.html
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2

Hi Sylvain,

I am forwarding your request to the Geotools list. There are people there who are far more knowledgeable about referencing systems and in particular the GeoServer implementation and can better answer your question.

springrider wrote:

Good afternoon

I need to display some maps which are centered on the Pacific Ocean. After
having spend some times, looking at the different SRS available in
GeoServer, i run a bunch of test with the EPSG=3349.
This is the type of map, i obtain: http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:3349 It is effectively centered on the Pacific ocean but, many polygons are not
correctly displayed.

Normal view with EPSG:4326:

http://www.fao.org/figis/geoserver/wms?bbox=-198.0,-98.68118000000004,198.0,92.30478000000085&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:4326

Is it a bug of GeoServer or did I make some mistakes defining the parameters
of my map?Is it the correct SRS with the right bounding box?

My data is extracted from an Oracle DB and i am using GeoServer 1.6.5. I
tried with the 1.7.0-RC1-pre version, it have obtained a white page.

Thanks for helping me.

Sylvain

--
Justin Deoliveira
Software Engineer, OpenGeo
http://opengeo.org

3

This looks like a standard 'edge of the earth' issue. Your data has
been clipped so that these artifacts don't appear in EPSG:4326 (look
around Egvekinot). The problem here is that when a polygon, such as
Africa, extends beyond the edge of the map the points are being
projected to the other side of the view. The results are the horizontal
lines as the polygon races across the map. You will likely need to do
data preparation to split some continents across your edge of the world.

--
Mark Leslie
Geospatial Software Architect
LISAsoft

-------------------------------------------------------------
Ph: +61 2 8570 5000 Fax: +61 2 8570 5099 Mob: +61
Suite 112, Jones Bay Wharf 19-21 Pirrama Rd Pyrmont NSW 2009
-------------------------------------------------------------

LISAsoft is part of the A2end Group of Companies
http://www.ardec.com.au
http://www.lisasoft.com
http://www.terrapages.com

springrider wrote:

Good afternoon

I need to display some maps which are centered on the Pacific Ocean. After
having spend some times, looking at the different SRS available in
GeoServer, i run a bunch of test with the EPSG=3349.
This is the type of map, i obtain:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:3349
It is effectively centered on the Pacific ocean but, many polygons are not
correctly displayed.

Normal view with EPSG:4326:

http://www.fao.org/figis/geoserver/wms?bbox=-198.0,-98.68118000000004,198.0,92.30478000000085&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:4326

Is it a bug of GeoServer or did I make some mistakes defining the parameters
of my map?Is it the correct SRS with the right bounding box?

My data is extracted from an Oracle DB and i am using GeoServer 1.6.5. I
tried with the 1.7.0-RC1-pre version, it have obtained a white page.

Thanks for helping me.

Sylvain
  

4

Thanks for your replies.

I can not technically reshape my data. In fact from the same geographical
data source, i want to apply different projections (4326, Antartica
projection, pacific centered projection).

I need to find a solution to have my data projected based on a meridian
centered on the pacific.
Anyway, I think, there is a bug too. In fact, all the polygons which are cut
by the antimeridian are the ones not correctly displayed with the color
outside of the envelope because it seems in that configuration that the
polygons are not closed anymore. For Antartica, it is even worst, it's not
appearing anymore.
It is even more visible in that view:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:ISO3_COUNTRY&width=800&height=362&srs=EPSG:3349

Do i have to add this bug into JIRA for GeoServer of For GeoTools?
Do you have any other suggestions to eade this problem?

Thanks again for your help.

Sylvain

Mark Leslie-3 wrote:

This looks like a standard 'edge of the earth' issue. Your data has
been clipped so that these artifacts don't appear in EPSG:4326 (look
around Egvekinot). The problem here is that when a polygon, such as
Africa, extends beyond the edge of the map the points are being
projected to the other side of the view. The results are the horizontal
lines as the polygon races across the map. You will likely need to do
data preparation to split some continents across your edge of the world.

--
Mark Leslie
Geospatial Software Architect
LISAsoft

-------------------------------------------------------------
Ph: +61 2 8570 5000 Fax: +61 2 8570 5099 Mob: +61
Suite 112, Jones Bay Wharf 19-21 Pirrama Rd Pyrmont NSW 2009
-------------------------------------------------------------

LISAsoft is part of the A2end Group of Companies
http://www.ardec.com.au
http://www.lisasoft.com
http://www.terrapages.com

springrider wrote:

Good afternoon

I need to display some maps which are centered on the Pacific Ocean.
After
having spend some times, looking at the different SRS available in
GeoServer, i run a bunch of test with the EPSG=3349.
This is the type of map, i obtain:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:3349
It is effectively centered on the Pacific ocean but, many polygons are
not
correctly displayed.

Normal view with EPSG:4326:

http://www.fao.org/figis/geoserver/wms?bbox=-198.0,-98.68118000000004,198.0,92.30478000000085&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:UN_CONTINENT&width=800&height=362&srs=EPSG:4326

Is it a bug of GeoServer or did I make some mistakes defining the
parameters
of my map?Is it the correct SRS with the right bounding box?

My data is extracted from an Oracle DB and i am using GeoServer 1.6.5. I
tried with the 1.7.0-RC1-pre version, it have obtained a white page.

Thanks for helping me.

Sylvain
  
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View this message in context: http://www.nabble.com/Projection-centered-on-the-Pacific-Ocean-tp18983741p19050545.html
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5

springrider ha scritto:

Thanks for your replies.

I can not technically reshape my data. In fact from the same geographical
data source, i want to apply different projections (4326, Antartica
projection, pacific centered projection).

I need to find a solution to have my data projected based on a meridian
centered on the pacific.
Anyway, I think, there is a bug too. In fact, all the polygons which are cut
by the antimeridian are the ones not correctly displayed with the color
outside of the envelope because it seems in that configuration that the
polygons are not closed anymore. For Antartica, it is even worst, it's not
appearing anymore.
It is even more visible in that view: http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:ISO3_COUNTRY&width=800&height=362&srs=EPSG:3349

Do i have to add this bug into JIRA for GeoServer of For GeoTools?
Do you have any other suggestions to eade this problem?

At the moment it's not possible to do what you're asking for,
and the fix is definitely not trivial. We'd have to determine
the validity area of the destination projection, notice that
the polygons go beyond that, split them along the discontinuity
line, and render them separately.

Due to a bug in GT2 referencing, we cannot even guess where the
discontinuities are (http://jira.codehaus.org/browse/GEOT-1578).

Martin, any suggestion on how to deal with this case? How
do we figure out when polygon splitting is needed, and where?

Cheers
Andrea

6

Does anyone have any pointers on how to deal with the problem of
GeoServer not able to render polygons straddling the anti-meridian
correctly?

From what I've been reading this is still a "bug" in GeoServer

(GeoTools?) and that it cannot be fixed easily. I'm surprised this
hasn't been addressed. We're trying to "port" our Swing-based
application using OpenMap to a web-based one using
OpenLayers/GeoServer. OpenMap seems to handle our straddling
anti-meridian polygons just fine...

One solution I've read about is to take the offending polygons and
split them along the anti-meridian, but you'll end up with a line on
the anti-meridian without some fancy SLD action. Does anyone have any
code examples on how to do all this?

Many thanks in advance!

Rob

On Tue, Aug 19, 2008 at 1:07 PM, Andrea Aime <aaime@anonymised.com> wrote:

springrider ha scritto:

Thanks for your replies.

I can not technically reshape my data. In fact from the same geographical
data source, i want to apply different projections (4326, Antartica
projection, pacific centered projection).

I need to find a solution to have my data projected based on a meridian
centered on the pacific.
Anyway, I think, there is a bug too. In fact, all the polygons which are cut
by the antimeridian are the ones not correctly displayed with the color
outside of the envelope because it seems in that configuration that the
polygons are not closed anymore. For Antartica, it is even worst, it's not
appearing anymore.
It is even more visible in that view:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:ISO3_COUNTRY&width=800&height=362&srs=EPSG:3349

Do i have to add this bug into JIRA for GeoServer of For GeoTools?
Do you have any other suggestions to eade this problem?

At the moment it's not possible to do what you're asking for,
and the fix is definitely not trivial. We'd have to determine
the validity area of the destination projection, notice that
the polygons go beyond that, split them along the discontinuity
line, and render them separately.

Due to a bug in GT2 referencing, we cannot even guess where the
discontinuities are (http://jira.codehaus.org/browse/GEOT-1578).

Martin, any suggestion on how to deal with this case? How
do we figure out when polygon splitting is needed, and where?

Cheers
Andrea

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7

Hi,
I have been investigating this and similar problems myself even recently.
The problem, or better limitation, is at the geotools level and due to
the various checks performed on the Area of Definitions of the various
CRS.
Fixing/improving this is not going to be trivial, given also the
amount of code that depends on this part.

Simone.
-------------------------------------------------------
Ing. Simone Giannecchini
GeoSolutions S.A.S.
Owner - Software Engineer
Via Carignoni 51
55041 Camaiore (LU)
Italy

phone: +39 0584983027
fax: +39 0584983027
mob: +39 333 8128928

http://www.geo-solutions.it
http://simboss.blogspot.com/
http://www.linkedin.com/in/simonegiannecchini

-------------------------------------------------------

On Wed, Feb 4, 2009 at 4:02 PM, MrR08040 <MrR08040@anonymised.com> wrote:

Does anyone have any pointers on how to deal with the problem of
GeoServer not able to render polygons straddling the anti-meridian
correctly?

>From what I've been reading this is still a "bug" in GeoServer
(GeoTools?) and that it cannot be fixed easily. I'm surprised this
hasn't been addressed. We're trying to "port" our Swing-based
application using OpenMap to a web-based one using
OpenLayers/GeoServer. OpenMap seems to handle our straddling
anti-meridian polygons just fine...

One solution I've read about is to take the offending polygons and
split them along the anti-meridian, but you'll end up with a line on
the anti-meridian without some fancy SLD action. Does anyone have any
code examples on how to do all this?

Many thanks in advance!

Rob

On Tue, Aug 19, 2008 at 1:07 PM, Andrea Aime <aaime@anonymised.com> wrote:

springrider ha scritto:

Thanks for your replies.

I can not technically reshape my data. In fact from the same geographical
data source, i want to apply different projections (4326, Antartica
projection, pacific centered projection).

I need to find a solution to have my data projected based on a meridian
centered on the pacific.
Anyway, I think, there is a bug too. In fact, all the polygons which are cut
by the antimeridian are the ones not correctly displayed with the color
outside of the envelope because it seems in that configuration that the
polygons are not closed anymore. For Antartica, it is even worst, it's not
appearing anymore.
It is even more visible in that view:
http://www.fao.org/figis/geoserver/wms?bbox=-22041257.773878,-14322638.1338445,22041257.773878,13613811.2422463&styles=&Format=application/openlayers&request=GetMap&version=1.1.1&layers=fifao:ISO3_COUNTRY&width=800&height=362&srs=EPSG:3349

Do i have to add this bug into JIRA for GeoServer of For GeoTools?
Do you have any other suggestions to eade this problem?

At the moment it's not possible to do what you're asking for,
and the fix is definitely not trivial. We'd have to determine
the validity area of the destination projection, notice that
the polygons go beyond that, split them along the discontinuity
line, and render them separately.

Due to a bug in GT2 referencing, we cannot even guess where the
discontinuities are (http://jira.codehaus.org/browse/GEOT-1578).

Martin, any suggestion on how to deal with this case? How
do we figure out when polygon splitting is needed, and where?

Cheers
Andrea

-------------------------------------------------------------------------
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Build the coolest Linux based applications with Moblin SDK & win great prizes
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