Masó, J., Díaz, P., Riverola, A., Díaz. D. and Pons., X. (2013). Exchanging the Status between Clients of Geospatial Web Services and GIS applications using Atom. In Castillo, O., Douglas, c., Dagan Feng, D. and Lee., J. (Eds.), in proceedings of the International Multi Conference of Engineers and Computer Scientists 2013, Vol I. IMECS, March 2013, Hong Kong. ISBN: 978-988-19251-8-3.

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2. In geospatial analysis, several layers covering the region of interest are
overlaid, new information is derived and the results are presented in the formoverlaid, new information is derived and the results are presented in the form
of a composed map.
The distribution of this composed map can be done in several ways. 1.
generating a digital printing in GeoPDF format, drawback prevents the
further use of the information gathered and even its latter processing and
analysis. 2. Encapsulate all the data in a single file in a popular format such us
netCDF or HDF, or in a popular database file such as GeoPackage, the
disadvantage is that it results in big files disconnected from the producer
services and are limited to the region and purpose of the application.
Alternative proposed is the generation of an interoperable OWS (OGC Web
Services) Context document. Just a small document is transmitted with links
to external services and to information used. The recipient can operate with
the same status
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3. Conceptually, OWS Context is a list of metadata on a collection of
geospatial resources. Additionally, clients can present the information notgeospatial resources. Additionally, clients can present the information not
just as a list but also as a single overlaid map.
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4. The sources can be exchanged either by links to services or embedding GML
files that describe a geosourcefiles that describe a geosource
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5. Traditional WMS server-client interaction: A single request is send to the
server to get the complete image need to fill the view
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server to get the complete image need to fill the view

6. - In order to share the context do we need always an integrated client?
That is a good point again. The standard defines *a format*. It could define a
way to exchange it but it *does not*. This means that you can distribute it
by any means and you can try to see it in the way you can: IExplorer,
Googel reader, Google maps..., XLST transformations *but* the best way
to do it is using an integrated client that suports as many OGC formats and
types as possible.
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7. The OWS Context document is a ….. That those …. Is good for …
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8. The Atom Syndication Format is an XML language used for web feeds (A
web feed (or news feed) is a data format used for providing users withweb feed (or news feed) is a data format used for providing users with
frequently updated content)
A feed contains entries, along with various metadata.
The Atom format was developed as an alternative to RSS. RSS had
limitations and flaws, such as lack of on-going innovation and its necessity to
remain backward compatible— and that there were advantages to a fresh
design
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9. The model defines the structure of a document that has a generic section
defining overarching metadata about a collection or resources. The Atom filedefining overarching metadata about a collection or resources. The Atom file
starts and ends with a “feed”
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10. In this metadata we have common entries such as title, abstract, author, etc.,
but also specific entries about the geospatial extent of the area of interest.but also specific entries about the geospatial extent of the area of interest.
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11. Every source has a “owc:offering” that describes the geospatial content.
An offering can include 1. direct content of a geospatial data file in the form
of a href reference or embedded in some form of XML notation such as
GML or KML.
2. Services: Conceptually, all the MAP requests can be embedded in a
resource offering element by defining an operation that includes both the
elements needed for the request and the content returned by a previous
execution of the OGC services request.
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12. Since OWS Context has been designed as an Atom extension, it is possible to
see the document in common applications where Atom documents are valid.see the document in common applications where Atom documents are valid.
Some Internet browsers are able to present the document as a list of items
with title, abstract, time, description and download features
The browser identifies files and data in the Context document without any
further configuration.
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13. The use of GeoRSS in Atom and the embedded KML and GML content
allows the same document to be read by Google Maps as a list of items thatallows the same document to be read by Google Maps as a list of items that
have the extent, and in some cases the actual content, represented in a
dynamic map
Google maps: shows the rectangles of the bounding box
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14. (and in Bing Maps with limitations) Bing also reads the context document
properlyproperly
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15. Since the OWS Context Atom encoding is an XML and the references to the
services are included as full URLs, we have develop an XSL Transformationservices are included as full URLs, we have develop an XSL Transformation
(XSLT) to convert the Atom feed into an HTML5 document that shows the
exact status of the client view window that saved the context document.
The result is an overlaid map (static) with a legend that activates and
deactivates individual items
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16. Apart from Web browsers, the Context document can be read using GIS apps.
This is an example of the MiraMon application.This is an example of the MiraMon application.
When a context file is opened, the user is able to select the specific layers to
be added to the current view.
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17. This application is able to write a context document and read it again to
recover the context of the previous view, or load a context documentrecover the context of the previous view, or load a context document
generated by another application.
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18. It has the advantage that maps can be saved.
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21. Una de molt comú és perquè es va decidir posar una URL a un servei WMS
sencera i no posar el nom de servei i els paràmetres per separat. La raó éssencera i no posar el nom de servei i els paràmetres per separat. La raó és
permetre a clients tontos poder mostrar alguna cosa només usant la URL.
(sense entendre la sintaxi WMS). Això està mig discutit al document del ER.
La pregunta de com distribuir el fitxer i com llegir-lo és també molt comuna.
També hi ha la pregunta de si existeixen altre coses semblans. La resposta és:
Abans existia el WMC només per WMS's Cada programa té el seu propi
fitxer de projecte com el MMM, o l'ArcGIS etc. Els formats "tot en una sola
pastilla" proporcionen un suports similar com el KMZ, el NetCDF o el nou
GeoPackage (o el MMZ, clar).
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