Identification of Contour Lines from Average-Quality Scanned Topographic Maps

Figure 9

The extraction result from the second scanned topographic map. (a) Original scanned map. (b) The linear elements map. (c) The gray map. (d) Color segmentation result by the improved sFCM. (e) Color segmentation result by FCM. (f) The contour lines layer. (g) Contour lines layer after merged special runs. (h) Contour lines layer after node segments removal. (i) The resulting thinned contour lines. (j) The final repaired result. (k) Result of Chen et al. (l) Result of Samet et al.

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