Designing a map to overlay ArcGIS Online, Google Maps, or Bing Maps
Using ArcGIS Server, you can create map cache tiles that match the dimensions and scales used by ArcGIS Online, Google Maps, or Bing Maps. Matching the tile dimensions and scales of these online map services leads to a clean and fast-performing overlays inside your Web applications. If you plan on overlaying your map with ArcGIS Online services, Google Maps, or Bing Maps, follow this workflow when you create your map:
Author the map
You'll originally create the map in ArcMap by adding data and symbolizing it appropriately. When designing your map, you need to use the same coordinate system and scales used by ArcGIS Online services, Google Maps, and Bing Maps.
Change the coordinate system to WGS 1984 Web Mercator (Auxiliary Sphere)
The first thing you should do when designing the map is change the data frame coordinate system to the same one used by ArcGIS Online services, Google Maps, and Bing Maps, which is WGS 1984 Web Mercator (Auxiliary Sphere). To change the coordinate system, follow these steps:
- Right-click the data frame name (the default is Layers) in the ArcMap table of contents and click Properties.
- Click the Coordinate System tab.
- Click Predefined > Projected Coordinate Systems > World > WGS 1984 Web Mercator (Auxiliary Sphere), then click OK.
Earlier versions of ArcGIS recommended using the WGS 1984 Web Mercator projected coordinate system. The WGS 1984 Web Mercator (Auxiliary Sphere) coordinate system is an equivalent coordinate system that simplifies the datum transformations required for some datasets.
Design at the same scales used by ArcGIS Online services, Google Maps, and Bing Maps
Users of your map will see it at the scales used by ArcGIS Online services, Google Maps, and Bing Maps, so you should only design your map at those scales. But how do you know what those scales are?
You can load the scales into ArcMap's drop-down list of scales by doing the following:
- Open ArcMap and add some data.
- Click the drop-down list of scales and click Customize This List.
- Click Load and browse the list for the ArcGIS Online/Bing Maps/Google Maps scale set.
- Click OK to apply your changes and dismiss the dialog box. You can now see the set of scales used by these popular Web mapping services and easily jump between them using the drop-down list.
You only need to design your map to look good at the scales at which it will be cached. If you do not plan on caching your map at the larger scales, you do not need to do any design work at those scales.
Set scale ranges on your layers so that just the right amount of data and labels are visible at each scale, symbolized appropriately. When setting your scale ranges, avoid toggling layers on and off at or near the scales at which you are designing.
You may need to make copies of your layers so that you can symbolize them differently at various scales. The ArcMap table of contents can contain multiple copies of a layer, each with its own symbology and scale ranges. To copy a layer, right-click it in the ArcMap table of contents and click Copy. Then, right-click the data frame name and click Paste Layer(s).
Publish the map as a service
After you've finished authoring your map document (.mxd), you need to publish it as an ArcGIS Server map service before you can use it in your Web application. One of the easiest ways to do this is to right-click the map document in ArcCatalog and click Publish to ArcGIS Server.
Create a map cache
One of the reasons that ArcGIS Online services, Google Maps, and Bing Maps are so fast is that they use server-side map caching, meaning that predrawn images of the map are stored on the server so that you can quickly request them through a URL. With ArcGIS Server, you can create a similar cache for your map. Creating a map cache is recommended for optimum performance with all APIs and is required if you are using the ArcGIS Extension for Bing Maps.
The Map caches section contains much detail about planning, creating, and updating map caches. There are several ways to create a cache, but the following steps are essential:
- Right-click the service in ArcCatalog and click Service Properties.
- Click the Caching tab and choose to draw the map Using tiles from a cache that you will define below.
- Click Load tiling scheme from and choose ArcGIS Online / Bing Maps / Google Maps from the drop-down list.
- If necessary, change the Cache directory.
- Click Create Tiles. The caching tool appears with many values already filled in.
- Uncheck any scales for which you do not want to create the cache. If your map covers a big area and will not be viewed at large (zoomed-in) scales, you should uncheck the large scales.
- Set the update mode to Recreate All Tiles and click OK. The tool then creates the tiles.
Depending on how big your map is and the scales you've selected, it could take a long time to create all the tiles. See Planning a map cache to learn about factors that influence cache creation time. This topic also explains how storing your cache on a disk formatted with a small cluster size may help you avoid wasting disk space.
Once you've finished creating the cache, you're ready to use your map in a Web application on top of any of these services.