Trying to select orange or brownorange horizontals:
horizontals.jpg
paths.jpg
highway-mask.gif
convert highway_mask.gif -blur 0x4.0 -threshold 25%% highway_threshold_40.png
highway_threshold_40
convert highway_threshold_40.png -morphology Thinning:-1 Skeleton highway_thinned.gif
highway_thinned
Better quality and a little bit faster (+1/7):
convert highway_threshold_40.png -morphology Thinning:-1 Skeleton highway_thinned.gif
small blur
highway_blur_2
compare -metric RMSE -subimage-search highway_mask.png small_img_board_1.png result.png
subimage:
Or resize image
subimage:
the result after levels:
and back resized:
Water surface search on the same map:
subimage:
The result is weird:
Blend:
Water surface 2:
next try