What is an antonym of transect?

There isn't a perfect antonym for "transect" in the sense of a straight line across a geographical area. However, depending on the context, these words could be considered antonyms:

* Longitudinal: If "transect" refers to a line cutting across a geographical area, "longitudinal" would be a line running along its length.

* Encircling: If "transect" refers to a line cutting through an area, "encircling" would be a line that goes all the way around it.

* Parallel: If "transect" refers to a line cutting across a geographical area, "parallel" would refer to a line running alongside it, never intersecting.

* Indirect: If "transect" implies a direct path, "indirect" would suggest a roundabout or meandering route.

Ultimately, the best antonym will depend on the specific context in which "transect" is used.