public function locateBetween(LinearReferenceOpEvent $evt) {
        $geometry = $evt->getGeometry();
        $this->validGeometry($geometry);
        $mStart = $evt['mStart'];
        $mEnd = $evt['mEnd'];
        $offset = $evt['offset'];
        try {
            $results = $this->getLocateBetween($geometry, $mStart, $mEnd, $offset);
            $evt->setResults($results, true);
        } catch (OperationError $error) {
            $evt->addError($error);
        }
    }