WMTS stands for Web Map Tile Service. It is a standard protocol for serving map images as tiles over the internet. WMTS is designed to efficiently display maps in web applications, providing access to pre-rendered map tiles that can be easily integrated into various mapping services.

The critical characteristics of WMTS include:

1. Tile-based Structure
Instead of serving an entire map image at once, WMTS divides the map into small, pre-rendered tiles. These tiles are typically square and come in different zoom levels to provide different levels of detail.

2. Standardized Protocol
WMTS follows a standardized protocol defined by the Open Geospatial Consortium (OGC). This ensures interoperability and compatibility between different web mapping applications and services.

3. Efficient Rendering
Using pre-rendered tiles, WMTS allows for more efficient rendering of maps in web applications. As users zoom in or out, the application fetches the appropriate pre-rendered tiles for the desired level of detail.

4. Caching and Performance
WMTS benefits from caching mechanisms. Once a tile is requested and rendered, it can be cached on the client side or intermediate servers, improving performance for subsequent requests.

5. Scalability
WMTS is scalable and suitable for large-scale mapping applications. It efficiently manages the distribution of map tiles, making it feasible to display detailed maps even for large geographic areas.

6. Layered Architecture
WMTS supports the concept of layers, allowing multiple sets of map tiles to be served independently. This is beneficial for applications that overlay different information types on maps.

8. Integration with GIS
WMTS is commonly used with Geographic Information Systems (GIS) and web mapping frameworks to integrate maps into various applications, from desktop GIS software to online mapping platforms.

Popular web mapping services, such as Google Maps and OpenStreetMap, utilize tile-based approaches, although they may not strictly adhere to the WMTS standard. WMTS is particularly useful for developers and organizations creating custom web mapping applications that require a standardized way to access and display map tiles over the internet.