The matrix you are talking about is also called base, which generally refers to the landscape elements with the largest area and the best connectivity in the landscape.

There are three main criteria for judging which landscape type is the background or basement in the landscape:

First, the relative area. It is generally considered that the landscape type with the largest relative area is the basement. For example, in the grassland area of Inner Mongolia, the grassland ecosystem can be regarded as the background, with the largest area, which has a decisive influence on the process and function of the landscape. Others, such as roads and rivers, are corridors, while villages and towns and lakes are patches.

The second is to look at connectivity. If some components in the landscape are not the largest in area, but they are highly connected in the landscape, which has a very important impact on the logistics, energy flow and species transmission of the landscape, then this landscape type can also be called base or background.

The third is to see the dynamic control effect on the landscape. Generally speaking, the basement or background plays a leading role in controlling the structure, function and process of landscape ecosystem.

The above three standards generally do not conflict, but sometimes it is difficult to judge. The first two standards are easy to quantify and compare, and the third standard is difficult to quantify, which requires a deeper understanding of landscape ecosystem. In this case, you can consult experts who have a better understanding of the landscape ecosystem in this area.