add mtb:scale, mtb:scale:uphill, mtb:scale:imba (closes #2244)

data/presets/fields.json

@@ -571,6 +571,54 @@
         "label": "Speed Limit",
         "placeholder": "40, 50, 60..."
     },
+    "mtb/scale": {
+        "key": "mtb:scale",
+        "type": "combo",
+        "label": "Mountain Biking Difficulty",
+        "placeholder": "0, 1, 2, 3...",
+        "strings": {
+            "options": {
+                "0": "0: Solid gravel/packed earth, no obstacles, wide curves",
+                "1": "1: Some loose surface, small obstacles, wide curves",
+                "2": "2: Much loose surface, large obstacles, easy hairpins",
+                "3": "3: Slippery surface, large obstacles, tight hairpins",
+                "4": "4: Loose surface or boulders, dangerous hairpins",
+                "5": "5: Maximum difficulty, boulder fields, landslides",
+                "6": "6: Not rideable except by the very best mountain bikers"
+            }
+        }
+    },
+    "mtb/scale/imba": {
+        "key": "mtb:scale:imba",
+        "type": "combo",
+        "label": "IMBA Trail Difficulty",
+        "placeholder": "Easy, Medium, Difficult...",
+        "strings": {
+            "options": {
+                "0": "Easiest (white circle)",
+                "1": "Easy (green circle)",
+                "2": "Medium (blue square)",
+                "3": "Difficult (black diamond)",
+                "4": "Extremely Difficult (double black diamond)"
+            }
+        }
+    },
+    "mtb/scale/uphill": {
+        "key": "mtb:scale:uphill",
+        "type": "combo",
+        "label": "Mountain Biking Uphill Difficulty",
+        "placeholder": "0, 1, 2, 3...",
+        "strings": {
+            "options": {
+                "0": "0: Avg. incline <10%, gravel/packed earth, no obstacles",
+                "1": "1: Avg. incline <15%, gravel/packed earth, few small objects",
+                "2": "2: Avg. incline <20%, stable surface, fistsize rocks/roots",
+                "3": "3: Avg. incline <25%, variable surface, fistsize rocks/branches",
+                "4": "4: Avg. incline <30%, poor condition, big rocks/branches",
+                "5": "5: Very steep, bike generally needs to be pushed or carried"
+            }
+        }
+    },
     "name": {
         "key": "name",
         "type": "localized",
@@ -800,7 +848,7 @@
     "sac_scale": {
         "key": "sac_scale",
         "type": "combo",
-        "label": "Path Difficulty",
+        "label": "Hiking Difficulty",
         "placeholder": "Mountain Hiking, Alpine Hiking...",
         "strings": {
             "options": {
@@ -1001,7 +1049,7 @@
     "tracktype": {
         "key": "tracktype",
         "type": "combo",
-        "label": "Type",
+        "label": "Track Type",
         "placeholder": "Solid, Mostly Solid, Soft...",
         "strings": {
             "options": {