ESRI UC Day 3 - Building Mashups Using the ArcGIS Javascript API

Kun engelsk ...

This session I had in particular been looking forward to. I've seen and heard a lot about ArcGIS 9.3 and the new Javascript API making Mashups possible.

Jeremy Bartley and Jayant Sai were in control. First info was that the API is based on DOJO dijits. The Dojo Toolkit is a modular open source JavaScript toolkit (or library), designed to ease the rapid development of JavaScript- or Ajax-based applications and web sites.

Jeremy then went through some basic demos showing how simple it is to fire up a map viewer app. First just an ArcGIS Online based app, then a Mash with Virtual earth and lastly with Google Map.

Communication is HTTP, SOAP or REST. The REST capabilities a certain ArcGIS server presents is based on the services directory (I might be mistaken here but that was what JB said).

Info: Javascript is The one most used language in the world and has not changed sinces 1999.

The Javasvript API has a powerful eventing model making the basis for a rich client side design. This client has a map, a slider, navigation arrows and graphic layers. Some tools are available: Query, Identity and Search.

Key here is the access to Geoprocessing models on the server. Reason this is important that this is what makes ESRIs version so powerful. Neither Microsoft or Google has a geographic spatially enhanced back end.

As the javascript API develops different versions can sit side by side on the server. So back ward compatibility is solved by having all existing versions available.

JB and JS then demoed how this all works with Virtual Earth and Google Maps. Note that each of these Mashups require using a separete Javascript library each of which is specially designed to work with VE and GM. What ESRI have done is to make the object model of these JS libs resemble those of VE and GM making it easier for those using them also to use ESRIs js libs.

Especially the Google version was interesting because of the access to Google Mapplets - small widgets within GM.

Right now the js api is for pushing data out NOT to recieve. If you draw something in the client you yourslef will have to handle teh JSON code coming back. But it will probably come in future releases.

/Sik