             unit.fetch
                 success: =>
                     unit_list = new models.UnitList [unit]
-                    @clear_all_markers()
                     @draw_units unit_list, zoom: true, drawMarker: true
                 error: ->
                     # TODO: decide where to route if route has invalid unit id.

                    on_success?()

        draw_units: (unit_list, opts) ->
            markers = []
            if opts.service?
                color = colors.service_color(opts.service)

            unitCollection = new UnitCollection()
            unitCollection.fetch(
                success: (collection)=>
                    @draw_units collection, zoom: true, drawMarker: true
                error: ->
                    # TODO: what happens if no models are found with query?
