How to build online basemaps

GIS basemaps provide a visualization framework for all ArcGIS Server applications. In most cases, you will use a basemap, on top of which you can add your operational GIS layers. Operational layers refer to the map layers that your end users will work with such as layers that you edit or make notes on, layers that represent observations and sensor readings, layers that result from analytic models, and results from map queries.

Basemap alternatives

You have a number of alternatives when you create basemaps for use in your GIS map applications:

This section describes each of these alternatives and the implications of using each.

Creating a GIS map application that contains a number of independent map layers

In many traditional GIS applications, online maps are implemented as a series of independent map layers, where each map layer references a data source and can be toggled on and off in the map display. For example, the map below could be composed of a series of independent map overlays.

Typical organization of map layers in ArcMap
When using independent map layers in a Web map, each map layer is typically accessed as a separate map service. This flexibility enables you to combine layers from multiple servers. This can improve the flexibility of your Web map application. However, it can impact performance and simplicity. Not all map layers are designed to work together. In addition, performance can be slower.

This approach is considered to be flexible because each map layer service could potentially be used for a number of purposes.

This is how many ArcIMS map applications are implemented. You have some flexibility because you treat each map layer independently, and you can combine any series of layers in an ad hoc manner.

Performance can decrease if you try to incorporate many independent map services as individual map layers. The user experience for your audience is not as focused and can be perceived as being more complex. They need to know which layers to turn on and off and which to focus on in their work. Applications with many layers tend to lack focus in terms of mission-critical tasks and end-user workflows.

Using an ArcGIS Server basemap published by another organization

Many GIS organizations publish basemap services for use in other organizations. For example, a number of national mapping agencies and state and local government GIS organizations build, manage, and publish fundamental basemap datasets such as multiscale national maps (topographic maps), transportation maps, census maps, parcel maps, hydrology maps, and so on.

These maps are often intended to provide authoritative, accurate, and up-to-date basemap experience for your applications. They provide a very important enabling GIS map service that many other organizations can exploit to great benefit.

We expect an increasing number of users to begin publishing basemap services for use across the GIS community.

Adding your content to ArcGIS Online basemaps

ArcGIS Online basemaps are designed for users to extend by adding their own rich content, especially at larger, more zoomed-in map scales. This enables GIS organizations to leverage their primary content and create map services that take over where ArcGIS Online general maps leave off. See Designing a map to overlay ArcGIS Online, Google Maps, and Bing Maps to learn more.

Building and serving your own GIS basemaps

In many cases, you will need to build and serve your own basemaps for use in your applications. This is often the case when your organization is the GIS provider for a particular area of interest and in which your applications and frameworks require specific information themes (for example, parcels, engineering, facilities management, hydrology, utilities, geology, population and demographics, planning, and many other applications).

In these cases, you are typically already compiling fundamental, authoritative base information for one or more applications. This approach leverages content that your organization builds and maintains. In addition, this focuses support on your users by providing a framework or basemap that is fundamental to their daily operations.

The Map Templates page in the ArcGIS Resource Center provides some downloadable examples of basemaps that you can use to help you get started with your design.

Leveraging an existing Web map from Google Maps or Bing Maps onto which you add your operational GIS layers

Using a basemap from a widely used mapping Web service, such as Google Maps or Bing Maps, is very useful in many situations. Most end users will know about and have experience using one of these existing Web mapping applications. They are familiar and comfortable with the end-user experience.

Some GIS organizations serve content to citizens and other casual users in this framework but apply richer, more sophisticated map applications for their operational work.

It is important to note that these consumer basemaps will not support all use cases. Many applications require a more focused information background to provide context. For example, cadastral applications require a parcel framework. Many population mapping applications require administrative or political boundary maps, hydrology requires strong hydrological representations, and so on.

You'll need to weigh the ease of use of applying these consumer basemaps against the requirement that many users face to work with authoritative, up-to-date, locally compiled, and often sensitive content to address their workflows and missions.

In situations where you use Google Maps or Bing Maps, it's important to note that you may be restricted in your use of this information within your organization. You will need to have an appropriate map use license.

See Designing a map to overlay Google Maps or Bing Maps for steps on how to support this using ArcGIS.

Leveraging Google Earth as the basemap onto which you layer your operational information

Many of the same issues discussed above for Google Maps and Bing Maps apply for using Google Earth.

Even so, many GIS practitioners would like to mash up their GIS content for their end users using Google Earth, and this is readily done using ArcGIS support for KML. By default, each map service that you publish using ArcGIS Server will be available as a map service and as a KML network link.

See KML support in ArcGIS Server for more information.

A design checklist for map publishing with ArcGIS Server

Following is a useful checklist that can guide you in designing and creating basemaps for use in ArcGIS Server applications.