Precautions for using multiple map services in ArcGIS Server

As map data in a network application, it usually has different sources or uses, and is often organized and published as different services in an application. Program It is common to use multiple map services.
If a web app uses multiple map services, you need to set one of them as the primary map resource of the map control, the Service Changes determine the coordinate system and zoom levels of the entire map. For example, there is a service world, which uses the WGS84 coordinate system to make a four-scale cache and sets it as the primary map resource. The following situations may occur:
1. If another dynamic service named China that uses the Xi'an 1980 coordinate system needs to be superimposed with world:
The zoom level of a web app is only 4 levels, consistent with the World Service. During rendering, the World Data is retrieved from the cache, while the China data is dynamically projected on the server, then stack with world;

2. If there is another cached service named China that uses the Xi'an 1980 coordinate system (with a three-level cache, two of the two scales are consistent with the two scales in the world) that needs to be superimposed on the world:
For example, A is a China service and B is a World Service. The zoom level of the web app is still 4, which is determined by world. During rendering, The World Service takes the cache, and the scale of the China service is dynamically projected into the WGS84 coordinate system by the server, and images are dynamically generated for superposition (here, all the caches of the China service are already made in the white space). Moreover, China can only see this when the scale is scaled to 2, 3, and 4. This is because the scale 1 World Service does not exist, so there is no web app, and the scale 5 exceeds the maximum scale of the China cache, even if the image is dynamically generated, it will not be created. For the cached service, because the scale level is not consistent, the maximum and minimum scale of the dynamically generated image is not displayed when it exceeds the cache;

3. Like 2, cached service still has three levels, but the China coordinate system is also WGS84:
When the scale is scaled to scale 2 and 4, both services take cache; when the scale is 3, world takes cache and China dynamically creates, but no dynamic projection is needed; china is invisible when the scale is 5;

4. When China is doing cache, it has the same scale as world, and the coordinate system is the same:
Therefore, this is the most ideal situation. cache is used for data presentation, with the fastest speed.

therefore, if you want to overwrite your own data with ArcGIS online data, you should select the latter as the primary map Resource (in one case, you can use your service as the primary map resource, that is, the coordinate system of your data is the same as that of ArcGIS online or Google map, but the scale level of the cache is only a subset of them .); 2. For map documents of your data, select predefined> geographic coordinate systems> world> WGS 1984 in the data frame system. ArcMap dynamically projects your data to the coordinate system; 3. Select load an existing tiling scheme from ArcGIS online services during cache. This ensures that the scale level is the same as that of ArcGIS online. By default, ArcGIS online has a cache of more than 10 levels for its own data, you can create several levels, but refer to the previous analysis for possible situations. For data that needs to be superimposed with Google Map, steps 1, 2, and 3 are also shown above. Note that you should select predefined> projected coordinate systems> world> WGS 1984 web Mercator in step 2.
if an error occurs when you click load an existing tiling scheme in step 3, you may have skipped step 2. Conversion from: http://diligentpig.blogspot.com/2009/02/arcgis-server.html