[GeoNetwork-devel] Link Non-GeoNetwork Server Using CWS?

GeoNetwork GeoNetwork Developer
1

Hi, List,

I am new in the field and trying to link UniData THREDDS catalog server to GeoNetwork SDI. Is it possible to make the link supposed that THREDDS with CWS interface?

Or, could it be done by WCS interface? Is WCS for map portrayal service only?

Any comments?

Most appreciated!!

Best regards.

Shawn

2

Hi Shawn,
Sorry for the late response.
I'm not very clear on what you try to achieve so answering is a bit difficult. At this point GeoNetwork v2.1 alpha has a CSW interface on the catalog (as a server, so CSW clients can interact with it). There is no functionality in GeoNetwork to connect from the server to another catalog through the CSW interface (which is what you want to do if I understand the first part of your question!?).
The WCS (Web Coverage Service) is totally unrelated to CSW (Catalog Services for the Web) so it would not be an alternative from my understanding.
CIao,
Jeroen

On Jan 4, 2007, at 1:25 PM, Shawn Chen wrote:

Hi, List,

I am new in the field and trying to link UniData THREDDS catalog server to GeoNetwork SDI. Is it possible to make the link supposed that THREDDS with CWS interface?

Or, could it be done by WCS interface? Is WCS for map portrayal service only?

Any comments?

Most appreciated!!

Best regards.

Shawn

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3

Hi, Jeroen,

Thanks for the reply. Yes, I am looking at the interoperability between catalog servers and wondering if CSW interface can be the solution.

This may be a stupid question, but please bear with me.

If the CSW interface on the catalog server can only be accessed by CSW clients, how does two catalog communicate with each other? As my colleague claimed(not knowing if it is correct or not), data can shared among catalog servers. I am curious about what does that really means. Thanks for the help.

Best regards.

Shawn

________________________________

From: Jeroen Ticheler [mailto:Jeroen.Ticheler@anonymised.com]
Sent: Thu 11/01/2007 11:03 PM
To: Hsiang Yun Chen
Cc: geonetwork-devel@lists.sourceforge.net
Subject: Re: [GeoNetwork-devel] Link Non-GeoNetwork Server Using CWS?

Hi Shawn,
Sorry for the late response.
I'm not very clear on what you try to achieve so answering is a bit
difficult. At this point GeoNetwork v2.1 alpha has a CSW interface on
the catalog (as a server, so CSW clients can interact with it). There
is no functionality in GeoNetwork to connect from the server to
another catalog through the CSW interface (which is what you want to
do if I understand the first part of your question!?).
The WCS (Web Coverage Service) is totally unrelated to CSW (Catalog
Services for the Web) so it would not be an alternative from my
understanding.
CIao,
Jeroen

On Jan 4, 2007, at 1:25 PM, Shawn Chen wrote:

Hi, List,

I am new in the field and trying to link UniData THREDDS catalog
server to GeoNetwork SDI. Is it possible to make the link supposed
that THREDDS with CWS interface?

Or, could it be done by WCS interface? Is WCS for map portrayal
service only?

Any comments?

Most appreciated!!

Best regards.

Shawn

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projects/geonetwork

4

Hi Shawn,

You might want to read up on some OGC documents regarding web services like WMS, WCS, etc.
The way I understand it, is as follows:
WMS = Web Mapping Service => serves for map portrayal only (the web service gives you JPEG images of geographically bounded information (maps) on demand)
WCS = Web Catalog Service => web service that gives you a catalog of geographic info

OGC has defined standards for accessing these web services. This implies that, in order for clients and servers to use the services, they always have to follow the same, standardized access methods.
So yes, web services can be used by both "clients" (ie users who want to get a map from a WMS) and servers (ie other web services that request all maps from a WMS and integrate them into their own collection of maps). The servers use the same access methods as regular clients, so you could say that they play the role of client in their communication to the services.

But then again, I'm no expert in this, so maybe the others can correct me if I'm mistaken...

Best regards,

Tim

From: "Hsiang Yun Chen" <chen14742@anonymised.com>
To: "Jeroen Ticheler" <Jeroen.Ticheler@anonymised.com>
CC: geonetwork-devel@lists.sourceforge.net
Subject: Re: [GeoNetwork-devel] Link Non-GeoNetwork Server Using CWS?
Date: Fri, 12 Jan 2007 00:27:21 +0100

Hi, Jeroen,

Thanks for the reply. Yes, I am looking at the interoperability between catalog servers and wondering if CSW interface can be the solution.

This may be a stupid question, but please bear with me.

If the CSW interface on the catalog server can only be accessed by CSW clients, how does two catalog communicate with each other? As my colleague claimed(not knowing if it is correct or not), data can shared among catalog servers. I am curious about what does that really means. Thanks for the help.

Best regards.

Shawn

________________________________

From: Jeroen Ticheler [mailto:Jeroen.Ticheler@anonymised.com]
Sent: Thu 11/01/2007 11:03 PM
To: Hsiang Yun Chen
Cc: geonetwork-devel@lists.sourceforge.net
Subject: Re: [GeoNetwork-devel] Link Non-GeoNetwork Server Using CWS?

Hi Shawn,
Sorry for the late response.
I'm not very clear on what you try to achieve so answering is a bit
difficult. At this point GeoNetwork v2.1 alpha has a CSW interface on
the catalog (as a server, so CSW clients can interact with it). There
is no functionality in GeoNetwork to connect from the server to
another catalog through the CSW interface (which is what you want to
do if I understand the first part of your question!?).
The WCS (Web Coverage Service) is totally unrelated to CSW (Catalog
Services for the Web) so it would not be an alternative from my
understanding.
CIao,
Jeroen

On Jan 4, 2007, at 1:25 PM, Shawn Chen wrote:

> Hi, List,
>
> I am new in the field and trying to link UniData THREDDS catalog
> server to GeoNetwork SDI. Is it possible to make the link supposed
> that THREDDS with CWS interface?
>
> Or, could it be done by WCS interface? Is WCS for map portrayal
> service only?
>
> Any comments?
>
> Most appreciated!!
>
> Best regards.
>
> Shawn
>
> ----------------------------------------------------------------------
> ---
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to
> share your
> opinions on IT & business topics through brief surveys - and earn cash
> http://www.techsay.com/default.php?
> page=join.php&p=sourceforge&CID=DEVDEV
> _______________________________________________
> GeoNetwork-devel mailing list
> GeoNetwork-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/geonetwork-devel
> GeoNetwork OpenSource is maintained at http://sourceforge.net/
> projects/geonetwork

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5

Hi Shawn,

On Jan 12, 2007, at 12:27 AM, Hsiang Yun Chen wrote:

This may be a stupid question, but please bear with me.

Don't think its stupid to ask questions!

If the CSW interface on the catalog server can only be accessed by CSW clients, how does two catalog communicate with each other? As my colleague claimed(not knowing if it is correct or not), data can shared among catalog servers. I am curious about what does that really means.

There's a multitude of protocols for catalogs to communicate:

- CSW 2 is the new kid on the block. we implement CSW 2.0 based on the ISO application profile (content) using the HTTP and SOAP bindings. Harvesting is not part of the current implementation, although I foresee this to happen in the future.

But than there are other existing standards using different binding protocols.

- GeoNetwork implements the OGC CAT 1.0 standard using the so-called Z39.50 binding protocol since the project started. This is often referred to as Z39.50 or ISO 23950. Harvesting through this protocol has not been implemented.

- It also implements a custom protocol that allows harvesting (caching) from another GeoNetwork catalog. This is available in GN 2.0 and is further improved in version 2.1 with a GUI administration interface and with a transfer of e.g. thumbnails, privileges and logo's.

Than there is the OAI interface, something that allows Google for instance to index a catalog and can also be used for harvesting. This is also planned to be added to the catalog, although I'm waiting for a funding hitch to be resolved :frowning:

OK, hope that helps a bit.
Ciao,
Jeroen

Thanks for the help.

Best regards.

Shawn

________________________________

From: Jeroen Ticheler [mailto:Jeroen.Ticheler@anonymised.com]
Sent: Thu 11/01/2007 11:03 PM
To: Hsiang Yun Chen
Cc: geonetwork-devel@lists.sourceforge.net
Subject: Re: [GeoNetwork-devel] Link Non-GeoNetwork Server Using CWS?

Hi Shawn,
Sorry for the late response.
I'm not very clear on what you try to achieve so answering is a bit
difficult. At this point GeoNetwork v2.1 alpha has a CSW interface on
the catalog (as a server, so CSW clients can interact with it). There
is no functionality in GeoNetwork to connect from the server to
another catalog through the CSW interface (which is what you want to
do if I understand the first part of your question!?).
The WCS (Web Coverage Service) is totally unrelated to CSW (Catalog
Services for the Web) so it would not be an alternative from my
understanding.
CIao,
Jeroen

On Jan 4, 2007, at 1:25 PM, Shawn Chen wrote:

Hi, List,

I am new in the field and trying to link UniData THREDDS catalog
server to GeoNetwork SDI. Is it possible to make the link supposed
that THREDDS with CWS interface?

Or, could it be done by WCS interface? Is WCS for map portrayal
service only?

Any comments?

Most appreciated!!

Best regards.

Shawn

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Join SourceForge.net's Techsay panel and you'll get the chance to
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6

Just to help avoid more confusion in the confusing standards naming:

WCS stands for Web Coverage Service (a map service like standard dedicated to image/raster data)
CSW stands for Catalog Service for the Web (a catalog protocol and the follow up of CAT 1)

Ciao,
Jeroen

On Jan 12, 2007, at 8:55 AM, Tim Jacobs wrote:

WCS = Web Catalog Service => web service that gives you a catalog of geographic info

7

Hi, Jeroen and Tim

Thanks for the help.

If harvesting is only implemented using GN 2.0 on GeoNetwork for the time being, does that means this is the only interface that can be used to bridge a catalog that is not GeoNetwork server?

In the future, will harvesting using CSW 2 or Z39.50 be implemented on GeoNetwork? It would be nice to have one standard so that people from non-gis community (earth science in my case) can share their data using such interface. Wouldn't it?!

Cheers
Shawn

8

Hi Shawn,

On Jan 12, 2007, at 10:40 AM, Hsiang Yun Chen wrote:

Hi, Jeroen and Tim

Thanks for the help.

If harvesting is only implemented using GN 2.0 on GeoNetwork for the time being, does that means this is the only interface that can be used to bridge a catalog that is not GeoNetwork server?

In short, yes for the current stable software
- With some code added to GN, harvesting through Z39.50 based on CAT 1 should be possible I think, although with some limitations. (on the fly searches can already be done to remote catalogues, including ArcIMS's metadata catalog through Z39.50)
- Harvesting through CSW 2 will certainly be added at some point as I said.
- GN 2.1 will also have a harvesting from a web accessible folder so it can synch with a remote location that holds metadata in XML formatted files. This function is not ready yet.

In the future, will harvesting using CSW 2 or Z39.50 be implemented on GeoNetwork? It would be nice to have one standard so that people from non-gis community (earth science in my case) can share their data using such interface. Wouldn't it?!

As said, yes. For the non-gis community OAI will probably be more convenient (also planned for as said).

Ciao,
Jeroen

Cheers
Shawn