In this diagram, the solid line represents a sampling transect and the numbers represent sampling points along that transect. Under this method, the nearest feature of interest within a certain distance of each point is sampled. The dashed circles represent the maximum distance for sampling from each point. Because the sampling interval is 10 m, the maximum distance sampled from each point is 5 m in order to prevent repeat sampling.
In this particular diagram, beech trees are the feature of interest. Circles represent any tree, gray circles represent beech trees, and black circles represent beech trees that are sampled.
As you can see, a beech tree is sampled at point 1 and point 3, but not at point 2 because no beech trees were found within 5 m of point 2.
This nearest-feature method can be a good approach for getting an unbiased representative sample
if your feature of interest is fairly common at your field site and if you're able to run long transects or many transect through your site.