At the moment this section appears to be part of the introduction, while I would expect it to come near the end. When reading the spec for the first time, you probably want to read about the relations first as those are the meat of the specification itself, and then descend into the gritty details such as importing other streams.
Case in point, this section assumes the reader is already familiar with the (geospatial) relations, as it contains the first mention of WKT strings.
At the moment this section appears to be part of the introduction, while I would expect it to come near the end. When reading the spec for the first time, you probably want to read about the relations first as those are the meat of the specification itself, and then descend into the gritty details such as importing other streams.
Case in point, this section assumes the reader is already familiar with the (geospatial) relations, as it contains the first mention of WKT strings.