Clark County & the Web Application Development Framework

Clark County & theWeb

Application Development Framework

My background

• Bachelors of Science in Geography from UNR• Emphasis in Geographic Information Systems• Work experience in GIS:

– Internship with USDA Farm Service Agency– Hired full time by USDA NRCS– Employed with the county since May 2007

Scope of this Presentation

• Brief overview of the Web ADF

• Accumulation of resources that I have put together

• Highlight significant components

• Helpful hints and tips that I have found by working with the Web ADF

Application Development Framework

What is the Web ADF

• The Web ADF is not an application

• Provides a set of developer tools to be used with Visual Studio

• Convenience Classes

Getting Started

• An Integrated Development Environment– Visual Studio 2005 & .NET 2.0 Framework– Visual Studio Web Express

Callback Framework

• Communication between the client and server is central to any web application

• The default ASP.NET Web model uses a synchronous page postback

Client Callbacks

• The implementation of the Callback framework will dramatically improve the web mapping applications performance.

• Uses a modified version of the page life cycle

Life Cycle Comparison

AJAX

• This modified version of the page life cycle:– Makes the page more responsive by only

refreshing selected portions of a page– Allows interaction while still processing a callback– This is done by creating a new connection to the

server

JavaScript

• JavaScript is the language in which Ajax function are called

Developing Web Applications

• If you have developed with an IDE before you’ll find development with the ADF similar– Drag and drop controls– Set control properties– Programmatically define control behavior

• If any of the previous slides or above points are unfamiliar step back from GIS and investigate the above topics and working within a development environment

Web Manager

Using the Templates

Customizing Your Application

• There are two basic types of modifications:– Modifying properties of Web controls and

making basic HTML modifications. This is the equivalent of modifying the ArcIMSparam.js in the ArcIMS HTML Viewer applications (requires no programming)

– Programming with application programming interfaces (API)

Using the Manager• My suggestion in how to leverage the Web

Manager is to create an application, explore functionality, set break points, debug and see how the processes run and see how ESRI builds and utilizes its own application development framework

• Become familiar with how ESRI utilizes callbacks and JavaScript

• Start working with the ASP life cycle

Using the Manager continued• However the real power of the ADF is in your

ability to extend, customize and build your own applications

• The Manager is built for people with little or no programming experience.

• The template application is written to try and be flexible enough to cover all circumstances. This makes the code bloated and much of the functionality is a black box. This makes debugging difficult

• To create a custom application that is ready for deployment you need to build the application from the ground up

ADF Developer Kit Samples

The developer kit samples are another great resource on where to start working with a specific GIS functionality

Building Blocks of the Web ADF

• Web Controls

• Task Framework

• Common DataSource API

• Graphics & Consolidated Classes

Web Controls

Web Controls

• Major Web Controls included in the ADF:– Map– Navigation– Toolbar– Overview Map– Table of Contents– Magnifier, Scale bar and Measurement tool– Map Tips– Task Manger, Task Menu & Task Results– Resource Managers

Resource Managers

– Map Resource Manager– Geoprocessing Resource Manger– Geocode Resource Manager

Map Resource Manager• Allows you to:

– Add– Remove – Set the properties

Geoprocessing Resource Manager• Allows you to:

– Create & Remove Services– Set the properties for a resources that contain

geoprocessing capabilities.

• Geoprocessing tasks run on a published model or map document with an associated tool layer on the server

• The manager is built to work in conjunction with the task framework and specifically the geoprocessing task control

• Application Programmer Interfaces are also provided for the advanced developer to build custom tools.

Geocode Resource Manager

• Allows you to:– Add– Remove – Set the properties for any data source that provides

geocoding functionality

• The control is built to work in conjunction with the Task framework and specifically the Find Address Task

• Application Programmer Interfaces are also provided for the advanced developer to build custom tools.

Task Framework

Task Framework

• Tasks are defined as a set of related actions that provide a common results.

• The Web ADF task framework delivers an encapsulated web control that performs predefined functionality or tasks.

• The task framework delivers a set of easy to use tools for the basic GIS business operations in your application.

Available Tasks

• Navigation• Find Address• Find Place• Geoprocessing• Query Attributes• Search by Attributes• Editing• These tasks take nothing more than dragging

and dropping. No programming is needed.

Task Controls

• Task Manager– Designed to organize tasks in a web application

• Task Results– Designed to store & display the results from

tasks

Custom Tasks & Extending Tasks

• The task framework provides the developer the ability to write custom tasks through its implementation classes

• The Developer can also, through extension, customize the out-of-the-box functionality for a specific task– Many classes and interfaces are exposed for

the advanced customization of the task framework

Data Sources and Resource Types• Data sources provide access to geospatial information,

analysis and processing capabilities. Data sources are consumed as resources.

• Each data source can have different capabilities which define the type of resource they provide.(map, geocode, geoprocessing)

• One resource can be used in many different ways, thus resources support different functionalities.

• Functionalities are used by the web ADF controls to work with a data source.

• The capability of a data source defines the type of functionalities available

• The foundation of the Web ADF is the ability to consolidate and utilize multiple data sources. It is founded on the ability to work with a common, defined set of resources and functionalities

Common Data Source API

Common Data Source API

• Previous versions of the ADF (ArcGIS Server ADF) only supported a single data source.

• The new Web ADF has improved in two ways:– Supports data from multiple sources– Ability to integrate and interact with data

from different sources

Common API

• The common API provides a generic framework by which a data source can be consolidated and utilized within the web ADF

• You can “Plug-in” your different data sources by implementing classes and interfaces of the Common API

Data Sources & API’s

The Web ADF provides developers with a set of objects to program with. The Common API exposes a set of course grained properties, methods and events which allows the developer to interact with different resource types but with the same code base. Most likely you are going to run into situations where the Common API will not provide you with the advanced functionality that you will need. This will then require you to use a data source specific API.

Data Source Specific API

• ArcGIS Server– SOAP– ArcObjects

• ArcIMS– ArcIMS

Basic Architecture of the Web ADF• Each web control works with a single resource manager

either directly or through another control• The Resource Manager manages access to the resource• When a control accesses a resource it generates a

collection of functionalities• The data source type defines which capabilities a

resource has• The resource manager type

dictates the capabilities of a

resource it needs to utilize

Basic Architecture continued• With this multi-source environment there is the

need of a Common API to define or standardize the interaction between the multi-source Web controls and data source specific business objects

• The Common API defines an abstract contract to allow interaction between multiple data sources

• These abstract contracts are interfaces and each data source type implements these interfaces and are utilized by the web controls to perform tasks

Graphics & Consolidation Classes

Graphics & Consolidation ClassesHow do you perform analysis using data from multiple resources and then display the results into a common environment?

Graphics & Consolidation Classes

• The consolidated classes include such classes as:– Geometry– Spatial Reference– Query– Spatial Filters

• The Web ADF also manages a set of classes that support web-tier graphics data sets and layers using web geometry, symbols and renderers.

• Most of the graphics and consolidation classes are located in the ESRI.ArcGIS.ADF.Web.dll. This assembly contains a number of namespaces to categorize its contents.

Tiers

Converting between types

• Due to the multi-source environment that is now available with the Web ADF converting between data types becomes a necessity in the application development environment.

• Because the Web ADF integrates and consolidates client-tier interaction with a web-tier application that works with data sources that are on the server-tier the responsibility is left to the developer to convert between data types.

Common Problems

Project Management• Due to the large size of the Web ADF it is easy

to get side tracked• Don’t start until you have a clear and defined

scope• Define your business needs and design

requirements before you even write a line of code

• Separate your layer:– Business– Data management– Presentation

• Read a best practices approach book

ASP & AJAX

• You have to understand how these lifecycles work to build a working and useful application– Maintaining state

– Updating multiple controls with one callback

– Displaying results other than in the task results

Where to get HELP• EDN Discussion Forums

– ArcIMS Product Discussion Conference• ArcIMS: .NET Developers

– ArcGIS Server .NET• .Net General questions• .Net Web ADF

• ArcGIS Server Development Blog– http://blogs.esri.com/Dev/blogs/arcgisserver/

• Object Model Diagrams– C:\Program Files\ArcGIS\DeveloperKit\Diagrams\Server

• ESRI online Class References– Search on specific interfaces and exposed members

LinksArcGIS Server BLOG

http://blogs.esri.com/Dev/blogs/arcgisserver/

EDN& VS

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/vsnet_integration.htm

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/building_first_app_overview.htm

 MSDN

http://msdn2.microsoft.com/en-us/library/ms178472.aspx

 AJAX

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/ajax_callback.htm

 Using the manager

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/manager/applications/tutorial_create_app.htm

 Map Resource Manager

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/control_mapresourcemanager.htm

 Geoprocessing Resource Manager

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/control_geoprocessingresourcemanager.htm

 Geocoding Resource Manager

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/control_geocoderesourcemanager.htm

 Tasks

http://blogs.esri.com/Dev/blogs/arcgisserver/

Data Source API’s

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/access_datasource_api.htm Graphics and Consolodated Classes

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/graphics_consolidation.htm

Type Conversion

http://edndoc.esri.com/arcobjects/9.2/NET_Server_Doc/developer/ADF/conversion.htm

Dustin W. NelsonDwnelson@co.clark.nv.us