A method of operating a shape sensing apparatus comprises receiving shape data from a first shape sensor. The first shape sensor includes a first plurality of optical cores extending between a first section and a second section of an elongated optical fiber. The method further comprises receiving shape data from a second shape sensor. The second shape sensor includes a second plurality of optical cores extending between the first and second sections of the elongated optical fiber. The method further comprises determining a shape of the elongated optical fiber between the first and second sections by combining the shape data from the first and second shape sensors.