rails route not working but not sure why

Question

Another adopted rails app issue. I have the following in my routes.rb file. It is currently not working (not sure if it ever was). We have upgraded from 3.1 -> 3.2.13

scope '/arc' do 
    match '/api/get-images-by-location/:global_id' => 'api#get_images_by_location'
end

and I get the following error:

ActionController::RoutingError (No route matches [GET] "/arc/api/get-images-by-location/168"):

Should this route be working? I think it should but clearly it isn't.

thx for any help

edit 1

Added namespace for arc