Mannheim Web 2.0 Systems Development

Plan Being an early-adopter Web 2.0 technologies Mashups Google Earth and kml XQuery and eXist

Being an Early Adopter Learning new technologies when: –No official textbooks –No definitive documentation –You need to get ahead of the game Use –Examples –Discussion groups –Application Programmer interfaces –Reading page sources –Digging and delving –Experimenting with small examples, smaller changes to larger examples –Keep a lab book (or a blog) of results and lessons learnt

Web 2.0 Key ideas –Sharing information (blogs, wikis, RSS, ICQ/IM, social book-marking) –Information reuse (mashups, tagging A couple of Key Technologies –Hosted applications (Basecamp, Campfire, Stikipad) –Mapping –XML

Individual Task Start a blog The blog will be submitted for evaluation Exercise results should be entered into the blog, with discussion Later you can edit the spreadsheet of all blogs with your name and blog address

Wiki This wiki has been developed to provide an overview of Web 2.0 stuff for this class and another running next year. Task (during the day) –Add a new page to the wiki and link it in to the appropriate place. Document this and reference the new page in your blog

Mashups Combining information from multiple sources –Application gets data from a source Page-scraping (parsing HTML) Application Programmer Interface (API) –SOAP / REST /JavaScript functions RSS (Real Simple Syndication) E.g. –housing

TASK (in Pairs) Browse through ProgrammeableWeb and select a mash-up of interest. – Questions to answer and document in your blog: –What sources of information are being used? –How is the data obtained technically? –How are the sources combined –How useful is this mashup? –What questions does it raise?

Google Earth Google Earth is a client-side application (needs a download) so not used in this list of Mashups Location-based browsing will be a big thing

Google Earth Demo StudentsOnline Google Earth operations –Creating Folders –Creating Placemarks –Editing Location and Description –Editing Icons –Saving as kml Partner Organisations map

Google Earth Task (pairs) Decide on a trip (last holiday), place (home town), news event for the pair to document using GE, or the CEMS partner map Create an overlay 20 minutes only – can finish in your own time! Save as kml

Understanding kml Experimental: –Use a text editor (Notepad, PFE32) to load the text file, change a description, save and reload (after deleting the original) –Use Word 2003 to load the file – what doesit tell you about the file? Online documentation– the Google Earth specification Draw a tree diagram to explain the general structure

Understanding Latitude and Longitude Lines of equal latitude Lines of equal longitude (0, 0) of the West coast of Africa 0 longitude is the Greenwich Meridian 0 latitude is the Equator +,+ +, - Bristol 51 ° 27 ‘19.08 “ N 2 ° 35’ 30.76” W 1 minute of latitude = 1 Nautical Mile = miles 60 seconds in 1 minute 60 minutes in 1 degree 360 degrees in a full circle 1 minute of longitude goes to zero at the poles GE Reference system is WGS84

Geocoding To determine the latitude and longitude of an address or postcode US zipcodes geocoded UK Postcodes –commercially available in bulk –Individual geocoding in Google Earth, Google Map ? Other countries.

Advanced Google Earth Icons –Style can be designed For each Placemark For a set of placemarks by creating a style with an id Small icons can be selected from the big pallette png’s – each is 32* 32 pixels, arranged in 8 rows of 8, numbered 0- 7 from the bottom-left. Specific icons can be selected with the appropriate x, y, h, w parameters

XML Well-formed –Tags nested, attributes quoted, single root ‘Self-describing’ –So you can guess at the meaning of each item of data Terms –Root –Element –Attribute –Child and Parent –Typed values and CDATA Draw a diagram (however you like) to show the general structure of a kml file Review the structures

Using an XML database kml is just text, so any scripting programme can generate it (PHP, ASP JSP etc) kml is XML so any XML tools can process it an XML database –Stores XML documents (and other things) –Provides an XQuery interpreter to query the documents and to generate new documents.

Exist database Exist: Working System: Students OnlineStudents Online My links: Student server Sandbox interface for executing simple queries Admin interface for browsing collections JavaStart interface for adding resources, XML files and XQuery files to the database

XPath A language for selecting nodes in a tree structure - TreesTrees

XQuery Michael Kays’s 10 minute tutorial10 minute tutorial Exist is similar – can’t set the context node in the Sandbox, but only one file like this so queries should still work (ignore any leading.) Go on the FLOWR tutorial

XQueries in EXist You can store XQueries in Exist –Save to a text file –Using the webstart client, ad them to your user area –Execute them by using the admin interface to locate the script and running it.

Added functions XQuery Functions –See w3schools –String functions… Exist functions –See eXist functions –Input HTTP request parameters…

Example Trip spreadsheet Trip2kml.xql

Final task Your task in pairs is to choose a news story for Google news Find using Google or a geocoder the location of places relevant to the story The class will agree a common format for geocoded news stories Adapt the XML spreadsheet to hold the data you need about the story Adapt the trip2kml XQuery to convert your story into a kml file Collect all the stories into one collection Create a query to find all the news stories about places within N miles of a given location