In this section, you'll learn key concepts for tile caching, including tile caching schemes. We'll look at some software options for tile caching, and finally you'll learn about the process associated with the GeoServer tile caching stack that we'll be using in this section.

Tile caching is very useful when you are working with background maps, or for static content that does not change very often or involve much interaction. An example of tile caching is OpenStreetMap (https://www.openstreetmap.org/#map=10/21.2516/86.7343), and you can see tile caching at work as we zoom in and out of the map; portions of the map are pre-rendered as tiles, little images, and then they're stitched together by the frontend OpenLayers client, as shown in the following screenshot:

This allows very complex cartography to be delivered very quickly to our...

In the last section, you learned the fundamentals of tile caching. In this section, you'll learn the ins and outs of setting up tile caching in GeoServer. First, you'll learn all the global and layer options for tile caching in the GeoServer web administration interface. Then, we'll look at these settings in the XML files under the GeoServer directory. Finally, you'll learn about gridsets and why these are important in building your tile-cache-backed app.

We disabled all of these other services in the previous section, as shown in the following screenshot, since we'll be using WMST, which is enabled in the Services portion of the sidebar:

You can set a number of global options that will be available on all new layers or layer groups that will be tiled. Let's look at a couple of these options:

The metatile size...

In the previous section, you learned how to configure GeoServer for tile caching. In this section, you will learn how to create a tile-backed OpenLayers app using the WMTS tile scheme. First, we'll look at a WMTS example in more detail. We'll examine the CapabilitiesResponse from our GeoServer endpoint, and finally we'll walk through the frontend code. WMTS is the current best practice for tile caching in GeoServer. You can think of it as the best of WMS and TMS, providing WMS-like syntax and capabilities with the tile grid coordinate performance of TMS. As with other OGC standards, the list of parameters for WMTS is available in the implementation standard document. The tile matrix set is based on pixel size, zoom levels, scale denominators, and bounding boxes. Essentially, more tiles will need to be generated at larger scales. You...

In the previous section, you learned how to create a tile-backed app using OpenLayers. In this section, we'll take a deeper dive into using the tile cache. We'll start by viewing the app we created in the last section in the browser. Next, we'll send a request for a tile generated by the app, but this time with the command-line utility curl. Finally, you'll learn about seeding and rendering the tile cache.

Here is the OpenLayers app that we created in the previous section:

We'll use Developer tools from the browser again to see a URL for a particular tile, and then see what that looks like in curl. You can see we have tile requests here to OpenStreetMap, and also to our GeoServer instance:

I'll just grab one of these link addresses, URLs, and then, moving over into the command line, if we already have curl installed, we can...

In the previous section, you learned how to use the GeoServer tile cache. In this section, you'll learn about resolving issues that may arise with tile caching. First, you'll learn how to resolve the most common source of tile caching errors: parameters. Next, you'll learn about issues arising from rendering tiles. Finally, we'll review some other issues that may occur. The following example is showing a particular URL that includes parameters running through curl, which you saw in the previous section:

I changed a parameter in this URL; the tile matrix is changed to be 28, 3857 :28. This is not a tile matrix parameter that exists in the gridset, so we get an error back: InvalidParameterValue, related to TILEMATRIX.

So, to resolve an error of this sort, you would need to add 385728 to the gridset for this layer. The general...

This concludes the chapter on using tile caching to make your app faster. This was a challenging chapter, so give yourself a pat on the back for getting through it. In this chapter, we used tiles, pre-rendered portions of a map, to allow your app to load more rapidly. I covered the material you need to know to get your tile cache up and running, and fix any issues that may occur. In the next chapter, you'll learn how to enable additional GeoServer capabilities and tune your GeoServer instance for even better performance.