Creating Tile Caches for use on ArcGIS.com

A new feature in the latest version of Arc2Earth is to create Tile Caches that can be published to and consumed by ArcGIS.com clients (ArcGIS Explorer Online, Flex APIs and the forthcoming iPhone app). Tile Caches are just visual representations of whatever you can display in ArcMap but they are not interactive, you cannot search, identify or edit them. In the near future, there will be another article on this site that will show you how to do exactly that using an Arc2Earth Cloud instance.

Some items you will need before starting:
1. ArcGIS 9.0 or greater
2. The latest version of Arc2Earth (get it here, new as of 5/28/10). You can use the Community Edition for testing but the created tiles will be watermarked.
3. An Amazon S3 account (get one here)
4. An ArcGIS.com account (free, get one get one here)

Setting Up Accounts

First, let's set up the stored Accounts information using the A2E Option window. Once you enter these values, they are encrypted and saved for easy later usage. On the A2E toolbar, click the Help menu item and select Options. Goto the Accounts tab.

In the image above, there are existing saved accounts already however you will probably need to hit the Add button to create your new accounts. When you click add (or edit later on), you will see the following window.

We will need to create two accounts, one for your Amazon S3 storage and one for ArcGIS.com. Select the Account type using the dropdown and fill the appropriate information. For Amazon S3, your Access and Secret keys should be emailed to you after you setup your account. It is also important to specify the "Default Bucket" for your S3 account, otherwise A2E will automatically create one for you (with a slightly cryptic name). An S3 Bucket name must be globally unique, that is, all users of S3 share the same namespace and no one can have the same bucket name. So, choose wisely but don't worry, you can alway change for the next export

The ArcGIS.com account is straight forward, provide your user name and password and then hit OK. Remember, these values are encrypted before saving to the A2E configuration file. Once we have saved the accounts, we are ready to move on to actually creating a Tile Cache.

Creating a Tile Cache

First, create a map that you would like to publish taking care to setup symbols, renderers and labels that will look best with the map scales that are used for World Mercator tile caches. ESRI has a great article on these map scales and how best to plan for your map for them here . Another good tip is to zoom in a small area of your map and export that first for testing. Once you are happy with the output, either use the "Export Full Map Extent" option of zoom to your final output area. All exports to S3 and ArcGIS.com are updated no matter how many times you export

Once your map is ready, we're ready to setup the A2E tile exporter. On the A2E Toolbar, click the Export menu item and select "Create Map Tiles"

General

1. Set the Name property to something unique for your data. This will be the name of your MapService as well, so it should be descriptive. Do not use any special characters or spaces
   
2. Fill in the metadata to give your map a Title and description. For more metadata, use the "Advanced" button on the Viewers tab
   
3. Set the Opacity of your map, by default there is none. A good value for overlay maps is 70, or 30% transparent
   
4. if you are exporting Raster data, make sure to set your Image Format to Jpeg

Levels

The default levels that will be exported are determined by your map's current extent, so they may not represent the total amount of levels you need. Use the level selectors to change these values but pay close attention to the number of tiles that this will create for map extent (see textbox to the right). The more tiles, the longer it will take to export

All of the other settings on this tab are for advanced users, you can leave them as is

Storage

This tab tells the exporter where to store your tiles. By default, they are created locally under your MyDocuments\KMLDocuments folder. You can change this location using the top textbox and it can be a network drive location.

1. Select Amazon S3 from the dropdown for your remote storage location.
   
2. Click the Accounts button and select the S3 account you created prior to this step
   
3. The values from the account will be set automatically however, you can change these manually afterwards. For instance, you could change the Bucket name to something other then your default value

Viewers

The final tab allows you specify how you want your newly created map tiles to be display. Many A2E users do not use these values at all, they simply use the tile cache that is created in their own web pages. However, with the advent of ArcGIS.com, you may want to use these new default values to publish your data. The ArcGIS.com are:

1. Create ArcGIS Server tile cache - Use this option to make your S3 storage look like a real ArcGIS Map Server. It is not a real map server though, it can only serve tiles and as such, it will not be usable from some client applications. Most notably, the ArcGIS.com javascript administration application, which makes heavy use of AJAX/JSONP and thus, needs a real server to interact with. Compiled application like ArcGIS Explorer Online, the Flex api and the iPhone app do not need JSONP and can work directly against the tile cache
   
2. Publish to ArcGIS.com - This option will use your ArcGIS.com account to publish both a MapServer and Web Map to your "My Contents" area.
   
3. Public Access - Uncheck this value if you would like to keep your Web Map private, you can then assign access to other Users or Groups using the tools on ArcGIS.com

Click the Export button and monitor the status of the process using the Progress Window. It is important to check this log when the export complete to see if anything has failed. Most notably, if any layers in your map do not have Spatial References set they will not display in your tiles and will show up in this log

When complete, click on the Preview button and you will launch your newly create ArcGIS Explorer Online Web map.

Online Demo - Click here