Spatial index for CouchDB Formula was removed
Last versions were
geocouch requires the following formulae to be installed:
couchdb 1.7.1_3 Document database server
erlang 20.3.2 Programming language for highly scalable real-time systems

Recent formula history

Andrew Janke Fold geocouch in to couchdb formula
Dominyk Tiller geocouch: more audit appeasing
M.S.Adityan geocouch: fix brew audit warnings
Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Tomasz Pajor geocouch: cleanup and fix formula.

Formula code at GitHub