4-Lecture7
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Geospatial Web Services<br />
Lecture 7
Interoperability and Web Services<br />
Standards<br />
• Interoperability is the capability to<br />
communicate, execute programs, or transfer<br />
data among various functional units in a<br />
manner that requires the user to have little or<br />
no knowledge of the unique characteristics of<br />
those units
Interoperability and Web Services<br />
Standards
Interoperability and Web Services<br />
Standards<br />
• Standards are an important way to achieve<br />
interoperability<br />
– Standards specify the interface that different<br />
vendors should know
Web Service Standards<br />
• OGC-founded in 1994 is a nonprofit<br />
international census based standards<br />
organization leading the development of<br />
geospatial services.<br />
– OGC launched OWS (OGC Web Services)
Web Service Standards<br />
• ISO/TC 211 (International Organization of<br />
Standardization, Technical Committee 211) –<br />
also founded in 1994. The standards are<br />
numbered starting at 19101.<br />
– ISO/TC 211 works closely with OGC
Web Service Standards<br />
• W3C: The world wide web consortium (W3C)<br />
is the main international standards<br />
organization for the web.<br />
– SOAP, XML, SVG
Web Service Standards<br />
• WMS-Web Map Service is an OGC and ISO<br />
standard for requesting and serving maps over<br />
internet.<br />
– Are rendered in PNG, GIF, or JPEG format
WMS<br />
• GetCapabilities: Request Service metadata<br />
from the server<br />
• GetMap: Request a map from the server<br />
• GetFeatureInfo: Retrieves information for a<br />
location on a map
Web Service Standards<br />
• WFS-Web Feature Service is an OGC standard<br />
for reading and writing geographic features in<br />
vector format.<br />
– A user can perform operations, including insert,<br />
update, delete and query
WFS<br />
• GetCapabilities: Request Service Metadata<br />
• DescribeFeatureDataType: Requests the structure<br />
of the feature type that the WFS supports<br />
• GetFeature: Retrieves a Geographic Feature and<br />
its attributes to match a filter query type<br />
• LockFeatures: Requests the server to lock on one<br />
or more feature for the duration of a transaction<br />
• Transaction: Requests the server to create,<br />
update, and delete, geographic features
Web Service Standards<br />
• WCS-Web Coverage Service supports<br />
electronic retrieval of geospatial data as<br />
“coverages” including satellite images, digital<br />
aerial photos, digital elevation data
WCS<br />
• GetCapabilities: Requests the service<br />
metadata XML<br />
• DescribeCoverage: Requests full description of<br />
one or more coverages<br />
• GetCoverage: Request a coverage within the<br />
selected geographic area
Assignment<br />
• Search a WMS, WFS and WCS
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