Web Service Standards

Transcription

1 Web Service Standards

2 Web Service Standards WMS: Web Map Service is an OGC and ISO standard for requesting and serving maps over the Internet. Maps produced by WMS are generally rendered in a pictorial format such as PNG, GIF or JPEG. WMS specifies the following operations: GetCapabilities GetMap GetFeatureInfo

3 Web Service Standards WFS: Web Feature Service is an OGC and ISO standard for reading and writing geographic features in vector format. With WFS, clients can perform operations including insert, update, delete and query for geospatial feature data residing on the server. WFS defines the following operations: GetCapabilities DescribeFeatureType GetFeature LockFeature Transaction

4 Web Service Standards WCS: Web Coverage Service supports electronic retrieval of geospatial data as coverages including satellite images, digital aerial photos, digital elevation and other continuous data. WCS differs from WMS in two key ways WCS returns raw data, while WMS returns a visual representation WCS is used for Raster Data while WFS is generally used for vector data WCS defines the following operations: GetCapabilities DescribeCoverage GetCoverage

5 Web Service Standards Related Standards Although these are not exactly Web service standards, these formats are often used geospatial Web services to transport geospatial feature information between Web services and Clients. GML Geography Markup Language KML Keyhole Markup Language GeoRSS- Geo Really Simple Syndication

6 Web Web 1.0 vs Web 2.0 vs Web 3.0 Web 1.0 The first implementation of the web represents the Web 1.0, which, according to Berners-Lee, could be considered the "read-only web." In other words, the early web allowed us to search for information and read it. There was very little in the way of user interaction or content contribution. eg. Shopping Cart Online Stores etc...

7 Web Web 1.0 vs Web 2.0 vs Web 3.0 Web 2.0 Currently, we are seeing the infancy of the Web 2.0, or the "read-write" web if we stick to Berners-Lee's method of describing it. The newly-introduced ability to contribute content and interact with other web users has dramatically changed the landscape of the web in a short time. eg. Facebook Youtube etc...

8 Web Web 1.0 vs Web 2.0 vs Web 3.0 Web 3.0 Rise of Web services and APIs- Application Programming Interfaces have started talks on Web 3.0. This will be considered as a read-write-execute Web, where users will be able to contribute to content, the content gets processed and is then being consumed by other users on the web. eg. Google Maps with Weather Cloud services etc...

9 Recap HTTP URL HTML Web Services Map Services Data Services Analytical Services Metadata Catalog Services - SOAP/REST Service Communication - WMS/WFS/WCS - GML/KML/GeoRSS

10 Geospatial Mashups

11 Geospatial Mashups Mashups The mashup, a hallmark of Web 2.0/3.0, is a genre of interactive Web applications that seamlessly integrate content retrieved from diverse web based resources to create innovative applications. Mashups are a sign of progress in many areas of geospatial science and technology Integration of multiple data layers or datasets, often from multiple sources, is one of the most common functional requirements of GIS applications

12 Steps to building a mashup: Geospatial Mashups Mashups 1. Identify the problems to solve and define the objectives to accomplish. 2. Search for the Web resouces you need by using Geoportals or Web portals. 3. Publish your content and functions when they are not available over the Web and when yours are better for the project at hand. 4. Organize the contents and functions into basemaps, operational layers and tools. 5. Implement your application through configuration or programming. 6. Test, enhance and deploy the application

13 Steps to building a mashup: Geospatial Mashups Mashups To Configure: Since existing geobrowsers and map viewers can mashup a variety of sources without programming, you may just need to change some configurations. eg. ArcGIS Online To Program: Based on the programming interfaces of the contents and functions you chose, you may need to write programs from scratch or use existing frameworks.