GPS Mountain Biking TrailsCarolina North

➲ Steps to complete Trail Mapping

● GPS Survey

● Post-Processing of GPS Data● Differential Correction● Attribute/Geometry Editing

● Trail Map Creation

● Future Considerations

GPS Mountain Biking TrailsCarolina 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

GPS Mountain Biking TrailsCarolina North

➲ Post-Processing of GPS Data

● Differential Correction & Attribution Correction● Pathfinder Office

● Geometry Editing ● ArcGIS

GPS Mountain Biking TrailsCarolina 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

Differential Correction SummaryHillsborough 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: Range Percentage ---------- ---------- 0-15cm - 15-30cm - 30-50cm - 0.5-1m 2.6% 1-2m 46.4% 2-5m 48.6% >5m 2.3%

GPS Mountain Biking TrailsCarolina 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

Trail Maps Raw (Uncorrected & Unedited)

Trail Maps Differentially Corrected & Edited

GPS Mountain Biking TrailsCarolina 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