Best Practices for Plotting Multiple Shape Layers Simultaneously in Salesforce Maps

When plotting multiple Shape Layers simultaneously in Salesforce Maps, you may encounter the "Merge Error" exception. The error message appears in the Maps user interface, in the lower right corner.

This error might occur when plotting 50+ layers simultaneously, by either:

• Using the Plot on Load function to plot multiple layers, or
• Using the Plot All action on a folder that includes multiple layers

The "Merge Error" exception comes from the Maps Geometry service, which rate limits the number of callouts that can be made in one block of time. The estimated limit is 180 callouts per 60 seconds. This does not necessarily mean that 180 layers can be plotted simultaneously in 60 seconds without hitting that platform limit. The number varies depending on the number of layers plotted in one operation, the number of geometry shapes in each layer, the shape size, the user's internet connection, and other factors.

The Draw on Map tool also relies on the Maps Geometry service to recall and plot selected shapes, so you may also encounter callout limits when using this feature.