ArcMap documents and Web maps

Maps provide the mechanism for how GIS is deployed and shared. Each interactive GIS map is a specification for how geographic information is brought together and portrayed.

When you create a map, you specify its map layers and their drawing order in the map. Each layer is used to symbolize and label a particular dataset. You also define what information can be accessed through the features in each layer and what additional operations can be performed on the layer, such as spatial analysis or editing.

You can save and share your map definitions as map documents. For example, you can give a copy of your GIS map to other users. This enables users to deploy the shared map in many applications and across many organizations.

ArcGIS users work with and share two primary interactive map types—ArcMap documents (and their layers) and GIS Web maps.

• ArcMap documents are the way that Desktop users share their professional GIS work with other Desktop users. Map documents are also used to publish maps and their underlying geographic information as map services and other GIS services using ArcGIS Server.
• Web maps are the mechanism for how map services can be shared and used in many clients online—for example, you can open and use Web maps in ArcGIS Desktop, ArcGIS Explorer, the iPhone, and other mobile clients. Both Desktop users and novice users can create and share Web maps.

Each type of map document is described in more detail here.

ArcMap documents

ArcMap documents and layers are created and used in ArcMap, which is the primary mapping application in ArcGIS.

Each ArcMap document contains the complete map specification—the set of map layers, their display properties, editing rules, analytical models, attribute access and reporting, and so on.

Once an ArcMap document is created and its various map properties are defined, all the properties of the GIS map are saved as well. This captures many layer properties and interaction settings—the data source; how the geographic data is symbolized, labeled, and visualized; which map scales are used and the layer appearance at each scale; specifications for tools (such as how a layer is edited and in what datasets the new features are stored); properties for working with attribute information; and so on.

These properties are captured and encapsulated in map packages and layer packages.

The map can also encapsulate exactly how features are edited, what attributes are used, and how they are displayed in pop-ups. The map package specifies the geodatabase that holds the data, the geoprocessing models (in other words, tools) that are used to derive new information sets, and the related tables that are used to connect additional attribute information to the map. All these settings are captured as part of the map.

Each ArcGIS map document can capture both the cartography as well as all other elements of geographic information—the geodatabase, editing templates and rules, analytic models, how you work with tables and charts, and so on.

Among the key information elements in a map document are the map's layers, and often users want to share and encapsulate layer information in an independent layer file or layer package as well.

Users can then share their maps and layers with one another, enabling many to view and use geographic information in a common way. Any ArcGIS Desktop user can get a copy of someone else's map or layer package, then simply double-click to open and work with these documents in ArcMap.

When you receive a map package (or layer package) from another user, you can download that package onto your computer, and your ArcGIS Desktop is transformed by the package—it can do all the same work that the user designed and built into their shared map package or layer package. Everything that the other user was able to do, you can now do as well.

In addition, these ArcGIS documents and packages can be published as map services on the Web. Using ArcGIS Server, users can turn any map, geodatabase, or model into a GIS Web service for sharing in a workgroup, throughout an enterprise, or openly in the cloud.

Encapsulating knowledge within maps and sharing maps and layers using ArcGIS Desktop

Document	Key properties	Shared as
Map document	Map name, summary, description, and so on List of map layers Geodatabase Geoprocessing tools Image services Properties for each layer	Map document (MXD) Map package with its data (MPK)
Layer	Layer name, summary, description, and so on Properties (name, metadata, map scales, data source, transparency, and so on) Attributes: Visible fields, alias names, display expressions, read-only versus update, and so on Symbology Labeling Editing properties Attachments to features Identify and pop-up properties Time-aware properties	Layer file (LYR) Layer package with its data (LPK) As one of the layers in a map document/package

See What is ArcMap? for more information about map documents and layers.

ArcGIS Web maps

An ArcGIS Web map is an organized set of map service layers that can be opened and used together as a single map. Web maps can be shared on the web and opened in any ArcGIS client application—for example, in ArcMap, ArcGIS Explorer Online, ArcGIS.com, iPhones, etc.

You can use a web browser to combine Web maps for creating and sharing your own web maps.

Web maps are how ArcGIS users share and disseminate their geographic information as Web map layers that reference rich GIS services. Individuals use ArcGIS Desktop and ArcGIS Server to create map services and other GIS services to share their rich information—map services, image services, editing services, geoprocessing services, and so forth. Once published, these can be discovered and used to create ArcGIS Web maps and used anywhere in the ArcGIS system.

Using this approach, each GIS organization can make its information available to nonspecialists. This also enables the integration of information across organizations, providing a strong basis for collaboration.

Key properties	Shared as:
Map title, summary, description, and so on A set of one of more map service URLs that comprise the basemap The ordered list of Web map URLs used as operational layers A list of tasks (for example, whether a layer can be queried) A set of widgets to use the operational layers (for example, for editing or for time-aware layers)	Web maps, which can be shared and used in all ArcGIS clients: ArcGIS Desktop ArcGIS Explorer Online Mobile applications (for example, iPhone, Windows Mobile) Web applications (JavaScript, Flex, and Silverlight) SharePoint Web sites

See Using Web maps at ArcGIS.com for more information.

Working with Web maps

Each Web map is essentially an organized set of map layers, and each map layer references a Web map service. This simple paradigm can enable delivery of many advanced GIS capabilities on the Web. For example:

Web maps support feature pop-ups and interactive reports

You can use the Web map to click and pop up information about features. Essentially, you reach through the map to access important information. This can be through simple attribute reports or rich experiences for information access using graphics and dynamic charts.

Web maps support analytic functions

GIS supports a comprehensive set of rich analytic tools for performing sophisticated geographic analysis. All model results can be viewed and brought to life as map layers. Analytic results might be generated interactively or they may be precomputed. The primary point is that rich GIS analysis can be shared and visualized by anyone using Web maps. It's simple to reference the results in Web maps.

Images courtesy of Philadephia Police Department and Adaptation Atlas, respectively.

Web maps support editing and data compilation

Users can digitize and enter features on Web maps. This enables many within a community to contribute rich content and observations for many interesting scenarios.

You can create your own Web maps by combining a set of published Web map services. First, you specify the set of Web maps that you want to use as a basemap. Then you can specify the set of Web maps that will be your operational overlays, how you interact with them, and what tools or capabilities will be included (editing, tools for working with time-aware layers, and so on).

In this fire response map example, incident commanders can easily sketch in their operational status and plans and rapidly share this information using Web maps.