BRouter trekking: cost by surface (dirt < gravel < sand, approved ranking)

Surface was only paved/unpaved binary - gravel, dirt and sand cost the same. Add a
surfacepenalty into costfactor so a dirt track beats a gravel one of the same tracktype
(asphalt 0 < compacted .2 < ground/dirt/earth .4 < cobblestone/sett .6 < gravel .9 <
clay 1.3 < grass/wood 1.5 < sand/mud 5). Canonical lookup values only. Verified on the
home RouteServer: engages on unpaved, doesn't distort paved routes. Untagged-ford
avoidance by estimated_river_class was tried and dropped - it forced 5x detours (flags
riverside ways, not only crossings); untagged fords stay shown (wetcross) + future marks.

tools/brouter-web-staging/profiles2/trekking-adventure.brf

@@ -137,6 +137,25 @@ assign adventurepenalty =
      if allow_adventure then 0
      else add ( if ford=yes|stepping_stones then 10000 else 0 )
               ( if or tracktype=grade5 trail_visibility=bad|horrible|no then 5000 else 0 )
+# NB: avoidance by estimated_river_class was tried and dropped — it flags riverside ways too,
+# not only crossings, so it forced 5x detours. Untagged fords are SHOWN instead (wetcross on
+# the preview) and will be handled by manual ground-truth marks.
+
+# Surface cost (approved ranking, singlespeed): asphalt < compacted < grunтовka(ground/dirt/
+# earth/soil) < cobblestone/sett < gravel(all) < clay < grass/wood < sand/mud(avoid). Added to
+# costfactor so a dirt track beats a gravel one of the same tracktype.
+# canonical lookup values only (aliases fold into them: paved=bricks/brick/chipseal,
+# concrete=cement, ground=soil, cobblestone=unhewn_cobblestone, grass=artificial_turf).
+assign surfacepenalty =
+     if      surface=asphalt|concrete|paved|paving_stones   then 0.0
+     else if surface=compacted                              then 0.2
+     else if surface=ground|dirt|earth                      then 0.4
+     else if surface=cobblestone|sett                       then 0.6
+     else if surface=gravel|fine_gravel|pebblestone|unpaved then 0.9
+     else if surface=clay                                   then 1.3
+     else if surface=grass|grass_paver|wood                 then 1.5
+     else if surface=sand|mud                               then 5.0
+     else 0.0
 
 assign initialcost =
      if ( equal initialclassifier classifier_ferry ) then 10000
@@ -308,6 +327,7 @@ assign costfactor
   add noise_penalty
   add traffic_penalty
   add adventurepenalty
+  add surfacepenalty
 
   #
   # apply oneway-and access-penalties

tools/brouter-web-staging/profiles2/trekking.brf

@@ -137,6 +137,25 @@ assign adventurepenalty =
      if allow_adventure then 0
      else add ( if ford=yes|stepping_stones then 10000 else 0 )
               ( if or tracktype=grade5 trail_visibility=bad|horrible|no then 5000 else 0 )
+# NB: avoidance by estimated_river_class was tried and dropped — it flags riverside ways too,
+# not only crossings, so it forced 5x detours. Untagged fords are SHOWN instead (wetcross on
+# the preview) and will be handled by manual ground-truth marks.
+
+# Surface cost (approved ranking, singlespeed): asphalt < compacted < grunтовka(ground/dirt/
+# earth/soil) < cobblestone/sett < gravel(all) < clay < grass/wood < sand/mud(avoid). Added to
+# costfactor so a dirt track beats a gravel one of the same tracktype.
+# canonical lookup values only (aliases fold into them: paved=bricks/brick/chipseal,
+# concrete=cement, ground=soil, cobblestone=unhewn_cobblestone, grass=artificial_turf).
+assign surfacepenalty =
+     if      surface=asphalt|concrete|paved|paving_stones   then 0.0
+     else if surface=compacted                              then 0.2
+     else if surface=ground|dirt|earth                      then 0.4
+     else if surface=cobblestone|sett                       then 0.6
+     else if surface=gravel|fine_gravel|pebblestone|unpaved then 0.9
+     else if surface=clay                                   then 1.3
+     else if surface=grass|grass_paver|wood                 then 1.5
+     else if surface=sand|mud                               then 5.0
+     else 0.0
 
 assign initialcost =
      if ( equal initialclassifier classifier_ferry ) then 10000
@@ -308,6 +327,7 @@ assign costfactor
   add noise_penalty
   add traffic_penalty
   add adventurepenalty
+  add surfacepenalty
 
   #
   # apply oneway-and access-penalties