[GRASSLIST:4969] to add cost infomation to a map

I’m new to GRASS. I want to define manually the cost information(speed) according
to the terrain types(hard bed desert, grass land, roads, etc) and process it wit
h ‘r.cost’. What would the process be like? It seems to me that a cost surface wo
uld be added to the map, and then run r.cost. But I don’t know the details. Thank
you.

Wang Sang

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