ESRI UC 2008 – “A Framework for Implementing GIS on the Web”
My first session this morning was “Framework for Building GIS Web Applications” with Clint Brown – Director of Software Products, ESRI.
“Everyone including your Grandma is using Google Earth so now you can finally explain what you do to family and friends and they’ll actually understand what you mean.”
So true. I’ve been trying to explain what I do to friends and family for the past 15 years and it wasn’t until Google Earth that the light actually turned on for them. Though it was a funny and applicable quote for most people, Clint went on to make an even more important point when he stated that
“Consumer maps like Google Earth/Google Maps and Virutal Earth have defined a new user experience and GIS applications will have to support this.” The expectations for GIS web applications have indeed changed as a result of these technologies. Given that these consumer products have essentially changed the way we think about how web based mapping applications should look and function, how should ESRI users go about creating similar types of applications? Clint described a four step framework for creating these Web 2.0 GIS applications to meet these requirements.
1. GIS Applications
- The programming is much simpler
- It doesn’t require any additional technology on the web application server. You simply need access to published web mapping applications somewhere on the web. Of course for most organizations this will mean that you do need to purchase ArcGIS Server. However, the point is a good one in that you can mashup the mapping services provided by your organization with other existing map services elsewhere on the web.
Of course technology does not exist in a vacuum and your web GIS application will only be useful to users if you meet their needs. Before building your application you need to identify your audience and the work tasks that they need to perform. You also need to identify the key information products that should be provided by the application.
2. Digital Base Map
In terms of the digital base map, the “consumer” mapping applications are essentially built using one map for each map scale. So, as you zoom in and out on the map, the application is toggling between the various base map versions. To simulate these various base maps in your web mapping application you will need to create group layers in the ArcMap table of contents. Each group layer should contain whatever information you want to represent at a specific scale. These layers will then turn on/off in your application as the user zooms in and out. As Clint mentioned, this is “really quite simple”. Assuming that you know how to create group layers in ArcMap containing your data and know how to set map scale drawing parameters you should be able to create these base layers easily. The prerequisite to that is obviously that you have obtained the data that you need to create the base map.
The other point that Clint made regarding your digital base map is that you don’t have to build it all. You should build maps for your area of interest or organizational responsibility and then take advantage of existing base maps such as ArcGIS Online, Google/Virtual Earth, and other GIS departments. Build the data for your area of interest and then leverage what already exists. Basically this is mashing up data from multiple providers for creating your digital base map data.
Finally, you will need to provide the ability to toggle between various basemap types. For example, in Google Maps you can toggle between vector maps, imagery, and hybrid. Your users will want to do this so make sure make sure you take the time to create the various base map types.
3. Define and Create Operational Map Layers
Operational map layers are non-base map layers that support the functionality provided by your application. Examples would include working layers, sensor feeds and observations, query results, and the results of analytical models created through geoprocessing tasks. Alternative ways to add operational information to your map applications include creating a map service for your operational layer, working with feature queries and the assignment of symbology.
4. Tasks and Tools in Your GIS Application
The final component of the framework is to add tools to work with your operational information. One of the most common tools is the Locator which allows your users to search for place names, addresses, points of interest, etc. The consumer mapping applications are really good at this, and you should plan to add this functionality. Additional tools include the use of map layers as interactive reports through popup description balloons, the ability to query, graph, report and visualize data that supports your map layers, and various tasks including geoprocessing models, queries, and other programs that your users might execute to generate a result.
Finally, Clint recommend a few final steps for implementing your application including the following:
- Plan for Hosting Strategies
- Test and refine your application, services, and contents
- Develop a strategy to maintain your website and content
In summary, Clint gave a really good fundamental overview of a development framework for building your Web 2.0 GIS applications. I was particulary pleased to see that ESRI has embraced the ease of use and capabilities provided by “consumer” mapping applications and extended it to include advanced GIS analysis and geoprocessing.