The ArcGIS.com Map Viewer allows you to quickly and easily create and share Web maps that tell interesting stories about your data. They may explain where people are buying homes, where sea surface temperature is changing, or where elephants migrate in the summer. These maps share information not just data.
Often, a Web map will display a map service with operational data (such as available stands of timber) on top of a map service with reference information (such as imagery or a shaded relief map). Sometimes a reference map service that contains boundaries or labels is placed on top of the other layers to create a "map sandwich": two reference layers with the "meat", or operational data, in between.
Here's how you can create a Web map with the ArcGIS.com Map Viewer:
Now you've created a basic map using the ArcGIS.com viewer. You can further customize the appearance of the map by defining an extent, modifying layer order and setting transparency for layers. You can also configure pop-up windows to display formatted text, images, charts and more. Here is an example of a Web map that displays several layers of data for Redlands, CA, including Redlands schools, transit stops and demographic data that show ethnic diversity.
Once you've customized the map click Share to view the options for sharing your Web map. You can share on the social media sites Facebook and Twitter, embed the map in an existing Web site, or select a template to create your own Web map application.
Click Make a Web Application to view a large and growing gallery of customizable templates you can use to create an application for your Web map. Click the thumbnail to preview the map to see how your data looks in the various templates. Spend some time exploring the templates and note that the templates offer various bits of functionality like legends, scale-bars, editing, identify tools and different layouts and color schemes.
Once you have found a template you like you can Publish or Download the template. Select Download to copy the template to your machine where you can configure the template, customize it to suit your needs, then deploy to your organization's Web server. Select Publish to publish the map as a web application. Once published you can edit the item details and make the application public. Some of the templates provided by Esri are configurable which means you can customize the application with your own look and feel. The configurable templates show a Customizable tooltip when you hover over the template thumbnail in the template gallery. You configure your application through its Item details page (after you publish).
Every map you save on ArcGIS.com has a unique identification code. This ID tells the template which map to display. After clicking Download, a dialog appears that lists the map ID. Copy it and save it in a safe place; you'll need it in the next step when you configure the template.
Unzip the downloaded template then open the index.html file in a text editor and replace the map ID with the one you copied from the download dialog.
//The ID for the map from ArcGIS.com webmap = '1e79439598494713b553f990a4040886'; //Enter a title, if no title is specified... title = "";
The readme.html file included with the downloaded template contains information on how to perform additional customizations like changing the title or subtitle and adding a custom logo. The readme also includes information on how to deploy the application to your Web server.
The ArcGIS JavaScript help includes many samples, a community forum, and documentation geared towards beginning programmers. With the API, you can customize the templates to perform queries, run geoprocessing operations, select and highlight map locations and much more. The API also contains several out of the box widgets that you can include in the application to add functionality. These include a basemap picker, similar to the one in the ArcGIS.com map viewer, map components (legend, scalebar, and overview map), a time slider for visualizing temporal changes, and an editor widget that allows users to edit GIS data in the map. Web editing, which is one of the most useful and exciting aspects of the JavaScript API, is allowed when the ArcGIS Server administrator has configured the Feature Access capability on the map service.
The templates make it easy to build a Web application that includes common map elements like a legend and scalebar and more advanced functionality like editing. The templates are easy to customize, start with minor changes like modifying the colors and fonts or adding an additional widget, as your comfort level with JavaScript, CSS, and HTML increase, you make additional modifications to the application.