ArcGIS Server Development Technical Exchange 2

1. whether the intersection of ArcGIS Engine and ArcGIS Server can be directly developed into a COM component using ArcGIS Engine, and then called by ArcGIS Server or through Web Services, use ArcGIS Server to call Web Services

You can use the engine to develop COM components, which are then directly called by the ArcGIS Server or integrated through classes. (However, the implementation and logic of the components provided by the engine should be separated, that is, the engine development component cannot have an interface, but can only use the engine to encapsulate components with specific functions, because the interface of IE and COM components cannot be integrated.) At the same time, the components provided by the engine must provide unified interfaces that meet the server requirements.

If you deploy it on a server, you can also integrate it through Web Services.

2. Develop Web ApplicationsProgramIs it possible to use only ArcGIS Server without ArcGIS Engine. What are the main advantages of using the engine?
To develop a web application, you can only use ArcGIS Server. You do not need ArcGIS Engine. Because the underlying APIs of server and engine are the same. The architecture mode depends on user requirements and specific applications. There are some differences between the two implementation methods.

3. Relationship between ArcGIS Server and ArcIMS.
Can ArcGIS Server replace ArcIMS? If not, what are their focuses? Can ArcGIS Server be used to publish map data? ArcGIS Server can replace ArcIMS, but it must have efficient servers and achieve good load balancing. ArcIMS is suitable for publishing high-performance map data. It provides relatively simple functions (only supports viewer operations), but its speed is significantly better than that of ArcGIS Server. ArcGIS Server can implement all the functions that the engine can implement, including some advanced GIS functions, such as spatial analysis.

4. ArcGIS Server Deployment Solution
Developed using ArcGIS Server, Windows 2003 Server is recommended for deployment, which is conducive to load balancing. You can also use 2000 Pro/XP, but it is best to use the server platform

5. Server objects
A server object is a coarse-grained ArcObjects Component that runs in a process on the SOC machine. ArcGIS Server comes with two out-of-the-box server objects:
. Esricarto. mapserver
. Esrilocation. geocodeserver

6. pool Type and status
pooled server objects are expected to be used in a stateless manner. as a developer, you are responsible for making sure that the state of the server object, or its associated objects, has not changed when you return the object to the pool (by releasing its context via releaseservercontext ). each time a user or application session makes a request to create a pooled server object, it's indeterminate which running instance it will get out of the pool; therefore, all instances must have the same State or applications will experience inconsistent behavior.

Non-pooled server objects can be used in a stateful manner. since nonpooled server objects and their contexts are destroyed when you release them, you need to hold onto them for as long as the State is important to you. when you call releaseservercontext, Or you allow the server context to go out of scope, the server object and its context are destroyed, purging any state changes you made.

7. Status Management
Stateful (when the status changes) -- Non-pooled server objects (or pooled server objects, but the original initial state can be restored when the returned server context is released, this is rare)
Stateless (State does not change)-pooled server objects (you can also use non-pooled server objects, but the status cannot change, which is rare)

8. Status Change
Method for calling the Server Object status:
Add/delete layers from map server objects
Change the Renderer of the layer in the Server Object

Method for calling the environment status: it can act on pooled or non-pooled server objects, but in pooled server objects, the application should not depend on a special environment before performing operations. If the application depends on the environment, you must set the required environment status before performing the operation.

9. the key to scalability lies in the status of the GIS server, keep application scalability standards
Use stateless GIS server
pooled server objects
reduce the time for applications to Control Server objects. Release server objects in a timely manner and do not rely solely on the. NET built-in garbage collection system