1. GPS Mountain Biking Trails Carolina North ➲ Steps to complete Trail Mapping ● GPS Survey ● Post-Processing of GPS Data ● Differential Correction ● Attribute/Geometry Editing ● Trail Map Creation ● Future Considerations

2. GPS Mountain Biking Trails Carolina North ➲ GPS Survey ● 2 Phase (Trail 3 & Trail 2 & Trail 3 Loop) ● Phase 1: class time ● poor sat coverage ● high PDOP vals (productivity over precision) ● PDOP = 20, elevation=5 degrees ● 4-5 sats, PRNs: 09, 18, 21, 24 ● Phase 2: saturday late morning/early afternoon ● better coverage into the afternoon ● lower PDOP vals ● PDOP = 6, elevation = 15 degrees ● 5-8 sats, PRNs: 02, 06, 07, 10, 21, 24, 26, 29

3. GPS Mountain Biking Trails Carolina North ➲ Post-Processing of GPS Data ● Differential Correction & Attribution Correction ● Pathfinder Office ● Geometry Editing ● ArcGIS

4. GPS Mountain Biking Trails Carolina North ➲ Differential Correction & Attribution Correction ● Differential Correction using Hillsborough CORs data ● Attribution correct consisted mostly of recorded by field & file naming due to input errors

5. Differential Correction Summary Hillsborough CORs ➲ Differential Correction Summary: ➲ 4 files processed. ➲ In these files: 1789 (98.5%) of 1816 selected positions were code corrected by post-processing ➲ Estimated accuracies for 1789 corrected positions are as follows: RangePercentage -------------------- 0-15cm - 15-30cm - 30-50cm - 0.5-1m 2.6% 1-2m 46.4% 2-5m 48.6% >5m 2.3%

6. GPS Mountain Biking Trails Carolina North ➲ Geometry Editing - ArcGIS ● Smoothing of trail features – MAO = 3 ● Deletion of erroneous trail vertices ● due to extremely high (12+) PDOP values on position recording. Coordinated ArcGIS with Pathfinder Office to determine ● Movement of Trail Nodes based on satellite background image

7. Trail Maps Raw (Uncorrected & Unedited)

8. Trail Maps Differentially Corrected & Edited

9. GPS Mountain Biking Trails Carolina North ➲ Future Recommendations ● Spend more time planning for GPS survey ● Utilize QuickPlan for best collection times ● Gather more input from all stakeholders to plan the data dictionary ● Tom's team ● Mountain Bikers