Reducing latency in presenting map interfaces at client devices

A system comprising:

• a first front-end server that receives, from client devices, requests for presentation of interactive map user interfaces that depict (i) a particular geographic region and (ii) account data for an online account, the account data including, for each of multiple different sub-regions of the particular geographic region, attribute data that represents how many user interactions with multiple different electronic content items of the online account occurred when the electronic content items were distributed to multiple different user devices that were located in the sub-region, wherein each of the electronic content items is different from the interactive map user interface;
• a map image file generator that:
• generates an image file representing an image of a rendered map canvas that depicts a map of the particular geographic region and that is larger than, and requires more memory to store than, the generated image file;
• detects one or more sub-regions within the image based at least on visual borders depicted by the image;
• and
• assigns a different visual characteristic to each of the different sub-regions within the image based on the attribute data for the different sub-regions, wherein different quantities of user interactions with the electronic content items are represented by the different visual characteristics;
• and
• a second front-end server that configures a user interface of the client device to present the image with each of the different sub-regions being presented using the different visual characteristic corresponding to the different sub-region.

A non-transitory computer storage medium encoded with a computer program, the program comprising instructions that when executed by one or more data processing apparatus cause the data processing apparatus to perform operations comprising:

• receiving, from a client device, a request for presentation of an interactive map user interface that depicts (i) a particular geographic region and (ii) account data for an online account, the account data including, for each of multiple different sub-regions of the particular geographic region, attribute data that represents how many user interactions with multiple different electronic content items of the online account occurred when the electronic content items were distributed to user devices that were located in the sub-region, wherein each of the electronic content items is different from the interactive map user interface;
• generating an image file representing an image of a rendered map canvas that depicts a map of the particular geographic region and that is larger than, and requires more memory to store than, the generated image file;
• detecting one or more sub-regions within the image based at least on visual borders depicted by the image;
• assigning a different visual characteristic to each of the different sub-regions within the image based on the attribute data for the different sub-regions, wherein different quantities of user interactions with the electronic content items are represented by the different visual characteristics;
• and
• configuring a user interface of the client device to present the image with each of the different sub-regions being presented using the different visual characteristic corresponding to the different sub-region.