I totally want to do this also!

Yes I use PostGIS with next.jdbc, but I am using strings :-(

So, I found https://github.com/atsman/clj-postgresql#postgis-types awhile back, not sure if this is the kind of thing you are looking for, if so, it should be straightforward to port to next.jdbc (I have already ported most of the rest of this library....) One thing I still do not grok is what datatype(s) are used on the Java/Clojure side .... https://github.com/atsman/clj-postgresql/blob/master/src/clj_postgresql/spatial.clj