Cache Tile Size

[JustinHunter]

Hey all,

Since I took over the GIS position in our company I'm making our first cache of our map, which is all of Canada. We deal mainly with street data, so the entire road network as well as building footprints, parks and several other layers we display on our map. I successfully created one using 1024x1024 as a trial, and after playing with labels a bit more I decided to re-cache before deploying my final map.

With that said... I have read in several places here on the forums, in ESRI blogs, as well as the help files that it suggests the tile size remain either 256x256 or 512x512, but it doesn't state why.

I'm curious why this suggestion is made, what the pros & cons are... I pretty much want more information so I can make my own informed decision based on information gathered here as well as our needs in the company.

Thanks so much.

[NelsonDe_Miranda · Accepted solution]

Hey Justin,

There are a number of reasons why you would want to keep the dimensions of a cache tile size to 256x256 or 512x512. However, it is not a requirement.

Client side loading - Think of who your clients are and what they'll be using the map for. With 256x256 tiles, the client is able to load parts of the map cache much more quickly. Thus, the map is populated with cache with small tiles before the complete image is done. The larger the tiles become, the longer the client has to wait for a response from the web server or gis server. Personally i have a short attention span and if im browsing map cache on a mobile device or on my desktop and I see that tiles aren't populating the screen my brain goes into panic mode and I start hitting refresh.

The beauty of using larger tiles is that cache generation may be quicker when working with simple labelling properties. Also their is some time being saved because the supertiles being used to render the cache are much larger and capture a larger geographic area.

At the end of the day, these are the two major things i consider.

When mashing up maps with bing or other online map providers most using 256x256 which makes the blending better. For example, you may have bing in the background of a web map which loads quickly. If you're overlaying another map  on top of that, then there is likely to be a delay in the time that map is drawn if it uses a larger tile size.

I hope this helps,

Nelson

[JustinHunter]

Ah, that helps. Since our server and all devices are used through our LAN I originally chose 1024x1024 - but after making some labeling changes I decided to re-do the cache as 256x256 and it's taking an much, much longer than it did to do 1024. I cannot confirm if that is due to the tile size change or the labeling changes.

Since I'm going to have to do this on a quarterly basis, as our new data is delivered, perhaps I'll consider re-doing a chunk of this as 1024 again to compare the time to create.

Thanks for your answer.

[ErikkRoss]

It just depends on what types of devices your users are going to be using and how large the map area is going to be. For  modern day web maps viewed on desktops/laptops, I like to use 1024x1024. If your map is going to be viewed on a desktop computer you are probably looking at a resolution of 1920x1080. So if your tiles are only 256x256 or 512x512 it is going to require something like 10-20 tiles to view the entire map. All of those tiles means more connections which slows things down a bit.

I have been using tiles of 1024x1024 and it seems to be working out pretty well. The number of connections is much lower because not as many tiles have to be downloaded. The overall download size is about the same, but fewer connections means it feels faster.

If your map is going to be used on mobile devices then 256x256 would be the way to go.

I checked Google maps this morning on my desktop and they are using 256x256. But I'm guessing that a majority of their usage is from mobile devices.