Pair slope
Input profile=road distance=120m deltaElevation=18m uphill
Output 15.0%, 8.5°, uphill 1:6.7, danger
Forestry road slope checker
Calculate slope from two points or from a route point list, then highlight hazardous segments.
Built for quick checks on forest roads, skid trails, and cable yarding routes around the world.
Switch between pair and route-list checks on one screen
See hazard segments in the table and profile chart
Share URLs and keep local state
Safety notice
- This tool is for quick slope checks. Local conditions, soil, surface condition, vehicle type, load, and machine method can change the decision.
- Whether it is a forest road, skid trail, or cable yarding route, final decisions should follow local standards and on-site checks.
- Cable yarding cannot be judged by slope alone. Check skyline and equipment conditions separately.
- Hazard labels are warnings, not proof of approval or compliance.
How to use
- Choose either pair mode or route-point-list mode.
- Choose a distance unit and a profile.
- Enter the distance and elevation change, or enter the point list.
- Review the hazard segments, then copy the result or the share URL if needed.
Samples
Downhill slope
Input profile=skid distance=80m deltaElevation=12m downhill
Output 15.0%, 8.5°, downhill 1:6.7, caution
Route point list
Input 0/320, 40/323, 90/332, 130/334, 170/342
Output Highlight hazard segments in the table and profile chart
Glossary
grade
The ratio of elevation change to horizontal distance. Percent grade is grade × 100.
chainage
Cumulative horizontal distance along the route. It becomes the reference for route-point segments.
skid trail
A trail used to move felled logs to the landing. Terminology varies by region.
cable yarding
A yarding method that uses a cable or skyline system. Slope matters, but slope alone is not enough.
Calculation formulas
grade = rise / run
grade% = grade * 100
angle° = atan(grade) * (180 / π)
1:n = 1 : (run / |rise|)
total ascent = Σ max(Δelevation, 0)
FAQ
Why do you use horizontal distance?
Because slope is defined against horizontal distance, not route length or surface length.
How do I enter chainage for route points?
Enter cumulative horizontal distance in increasing order. Each point must be farther along the route than the previous one.
How far does metric/imperial support go?
The tool switches distance and elevation units. The calculation stays the same; only the display is localized.
Are the thresholds universal?
No. Profiles are starting values. Switch to custom and tune them for the local conditions and machine method.
Can I use it for cable yarding?
Yes, for organizing slope data. It is not a substitute for skyline or equipment design.
Important notes
- Profiles are starting points. They are not fixed operating standards.
- Enter route points in increasing chainage order. If the order breaks, segment slope calculations break too.
- GPS or map auto-import is not part of v1. If needed, clean the data elsewhere and paste it in.