The most effective action is to configure the map service to use cached tiles. The service's characteristics—numerous detailed features, complex symbology, and infrequent updates—make it an ideal candidate for caching. Caching pre-renders the map at various scales and stores the images (tiles) on the server. When a user requests the map, the server returns these pre-rendered tiles instead of drawing the complex data on the fly. This dramatically improves drawing performance for data that is largely static, directly addressing the reported slowness.

B. Eliminate scale-dependent rendering: This would worsen performance. Scale-dependent rendering is an optimization technique that simplifies the map by showing fewer details at smaller scales, thus reducing the server's rendering load.

C. Use dedicated instances instead of shared instances: While dedicated instances can improve performance by allocating specific server resources, it does not solve the core issue of slow on-the-fly rendering. Caching eliminates the need for most on-the-fly rendering, making it a more direct and impactful solution for this specific problem.

1. Esri

ArcGIS Enterprise Documentation. (2024). Map Caching.

Section: "What is map caching?"

Content: "A map cache is a set of map tiles... The server can distribute these images whenever they are requested. It's much faster for the server to return a cached image than to draw the map each time... The most important reason to cache your map is to improve its performance." This directly supports using caching for performance.

2. Esri

ArcGIS Enterprise Documentation. (2024). Tune and configure services.

Section: "Anticipating and accommodating users"

Content: "The most effective strategy you can take to improve the performance of map services is to cache them. When you cache a map service

the server draws the map at a set of predefined scale levels and saves the images." This identifies caching as the primary performance strategy.

3. Esri

ArcGIS Pro Documentation. (2024). Author a map for publishing.

Section: "Performance tips"

Content: "Use scale ranges to limit the display of layers to only the scales at which they are needed... This prevents layers with a lot of detail from being drawn at small scales

which would slow down drawing performance." This confirms that eliminating scale-dependent rendering (Option B) is counterproductive.

4. Esri

ArcGIS Enterprise Documentation. (2024). Configure service instance settings.

Section: "Shared and dedicated instances"

Content: This section explains that dedicated instances are useful for heavily used services or those with long-running jobs. However

for slow drawing performance due to complex cartography on static data

caching is the recommended and more fundamental solution before adjusting instance models.