Clarification of Spatial Context

[Cary Peebles]

I am trying to use FDO to connect to a variety of data sources. I am a little unclear about the coordinate systems. The connection will display available spatial contexts and a geometric property will indicate it's associated spatial context. I have noticed that the associated spatial context does not always appear in the connection's list until that context is set as the active spatial context.

Are the geometry data returned in the coordinate system identified by the geometric property's associated spatial context or are they converted to one that is identified as active on the connection? Do I have to set the context on the connection each time I do a fetch of a geometry? For example, I am accesing two different shapefiles and they are in two different coordinate systems and I am a bit confused on how to properly work with the contexts.

[Dan Stoica]

FdoIActivateSpatialContext command has been deprecated. Which providers are still advertise it? SHP doesn't.

In any case, you should not use it since the geometric property's associated spatial context gives all the info you need.

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Cary Peebles
Sent: Thursday, May 14, 2009 8:34 AM
To: [hidden email]
Subject: [fdo-users] Clarification of Spatial Context


I am trying to use FDO to connect to a variety of data sources. I am a little
unclear about the coordinate systems. The connection will display available
spatial contexts and a geometric property will indicate it's associated
spatial context. I have noticed that the associated spatial context does not
always appear in the connection's list until that context is set as the
active spatial context.

Are the geometry data returned in the coordinate system identified by the
geometric property's associated spatial context or are they converted to one
that is identified as active on the connection? Do I have to set the context
on the connection each time I do a fetch of a geometry? For example, I am
accesing two different shapefiles and they are in two different coordinate
systems and I am a bit confused on how to properly work with the contexts.
--
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[Cary Peebles]

Some javascript/style in this post has been disabled (why?)

Thanks. I think the ArcSDE provider still supports it (3.3).  It is also the one that has geometric properties that refer to spatial contexts that do not show up when I list the contexts from the connection until I used the activate command. Without that I could not get the coordinate system information. The SHP provider is nicely behaved. Am I correct in understanding that the geometries returned have their coordinates always in terms of the coordinate system identified by the spatial context association of the geometric property for that feature class?

 

From: Dan Stoica (via Nabble) [mailto:[hidden email]]
Sent: Thursday, May 14, 2009 12:32 PM
To: Cary Peebles
Subject: RE: [fdo-users] Clarification of Spatial Context

 

FdoIActivateSpatialContext command has been deprecated. Which providers are still advertise it? SHP doesn't.

In any case, you should not use it since the geometric property's associated spatial context gives all the info you need.

-----Original Message-----
From: fdo-users-bounces@... [mailto:fdo-users-bounces@...] On Behalf Of Cary Peebles
Sent: Thursday, May 14, 2009 8:34 AM
To: fdo-users@...
Subject: [fdo-users] Clarification of Spatial Context


I am trying to use FDO to connect to a variety of data sources. I am a little
unclear about the coordinate systems. The connection will display available
spatial contexts and a geometric property will indicate it's associated
spatial context. I have noticed that the associated spatial context does not
always appear in the connection's list until that context is set as the
active spatial context.

Are the geometry data returned in the coordinate system identified by the
geometric property's associated spatial context or are they converted to one
that is identified as active on the connection? Do I have to set the context
on the connection each time I do a fetch of a geometry? For example, I am
accesing two different shapefiles and they are in two different coordinate
systems and I am a bit confused on how to properly work with the contexts.
--
View this message in context: http://n2.nabble.com/Clarification-of-Spatial-Context-tp2889778p2889778.html
Sent from the FDO Users mailing list archive at Nabble.com.

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[Dan Stoica]

Some javascript/style in this post has been disabled (why?)

See inline…

 

From: [hidden email] [mailto:[hidden email]] On Behalf Of Cary Peebles
Sent: Thursday, May 14, 2009 12:40 PM
To: [hidden email]
Subject: RE: [fdo-users] Clarification of Spatial Context

 

Ø  Thanks. I think the ArcSDE provider still supports it (3.3).  It is also the one that has geometric properties that refer to spatial contexts that do not show up when I list the contexts from the connection until I used the activate command. Without that I could not get the coordinate system information.

You might be right about ArcSDE. I had a quick look and indeed ActivateSpatialContext is implemented but I cannot see how the behavior you see is possible. Maybe is a bug?  

Ø  The SHP provider is nicely behaved. Am I correct in understanding that the geometries returned have their coordinates always in terms of the coordinate system identified by the spatial context association of the geometric property for that feature class?

 Yes, you are correct.

From: Dan Stoica (via Nabble) [mailto:ml-user+64177-1034266727@...]
Sent: Thursday, May 14, 2009 12:32 PM
To: Cary Peebles
Subject: RE: [fdo-users] Clarification of Spatial Context

 

FdoIActivateSpatialContext command has been deprecated. Which providers are still advertise it? SHP doesn't.

In any case, you should not use it since the geometric property's associated spatial context gives all the info you need.

-----Original Message-----
From: fdo-users-bounces@... [mailto:fdo-users-bounces@...] On Behalf Of Cary Peebles
Sent: Thursday, May 14, 2009 8:34 AM
To: fdo-users@...
Subject: [fdo-users] Clarification of Spatial Context


I am trying to use FDO to connect to a variety of data sources. I am a little
unclear about the coordinate systems. The connection will display available
spatial contexts and a geometric property will indicate it's associated
spatial context. I have noticed that the associated spatial context does not
always appear in the connection's list until that context is set as the
active spatial context.

Are the geometry data returned in the coordinate system identified by the
geometric property's associated spatial context or are they converted to one
that is identified as active on the connection? Do I have to set the context
on the connection each time I do a fetch of a geometry? For example, I am
accesing two different shapefiles and they are in two different coordinate
systems and I am a bit confused on how to properly work with the contexts.
--
View this message in context: http://n2.nabble.com/Clarification-of-Spatial-Context-tp2889778p2889778.html
Sent from the FDO Users mailing list archive at Nabble.com.

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You can reply by email or by visting the link above.

 

 

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View this message in context: RE: [fdo-users] Clarification of Spatial Context
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