1. Mapping Little River Regional Park with GPS By: Jordan McMillen and Steven Loy April 23, 2008 Geography 594

2. Overview Produce accurate, usable map of advanced mountain bike section Important Steps: – Data dictionary – Data collection – Data processing Correction, smoothing – Outputs

3. Site About half of LRRP adv. mtn. bike trail Moderately hilly, pine and hardwood tree cover, many animals Qualifiers, informational markings

4. Data Dictionary and Collection Previsit to determine needs, scope, potential problems Collection visit to get data 2 Trimble GEO XT/XH receivers One used for line only, one for points only

5. Data Dictionary and Collection (cont.) Difficulties: – Tree cover limiting accuracy – Non standardized protocol for some features – Using Data Dictionary Improvements: – External antennas, keypad inputs – Greater planning, coordination, testing

6. Differential Correction --------Base Data Details:-------------------- Using reference position from base provider: Name: COOP_CORS, Durham, NC Position: 35°59'46.15538"N, 78°53'58.04671"W, 116.21 m Source: C:\Documents and Settings\geoglab319-01\My Documents\GPS Projects\Default\Base\COOP_CORS, Durham, NC durh100u.zip Local time: 4/9/2008 3:59:46 PM to 4/9/2008 4:59:41 PM Position: 35°59'46.12951"N, 78°53'58.03734"W, 117.47 m, 0.00 m Antenna height Distance from base provider: 0.83m durh100v.zip Local time: 4/9/2008 4:59:46 PM to 4/9/2008 5:59:41 PM Position: 35°59'46.12951"N, 78°53'58.03734"W, 117.47 m, 0.00 m Antenna height Distance from base provider: 0.83m --------Coverage Details:-------------------- Rover file: LR_04092008.SSF Local time: 4/9/2008 4:04:52 PM to 4/9/2008 5:51:51 PM 100% total coverage 51% coverage by durh100u.zip 49% coverage by durh100v.zip Code processing... Selected 4677 positions for post-processing Corrected 4560 positions Failed to correct 96 positions 95 of these were due to insufficient satellites for position fix 1 of these were due to unknown receiver type Excluded 22 positions 22 of these were due to high DOP values Filtered out 118 uncorrected positions RangePercentage -------------------- 0.5-1m 1.9% 1-2m 39.8% 2-5m 50.5% >5m 7.8%

7. Data Corrections Manual Edits – 1. Merge Process – 2. Editor Toolbar

8. Data Correction Continued… Generalization Importance of Maximum allowable offsets

9. Editting Process Smoothing – Methods of smoothing – Chosen method and reasoning

10. Final Results Final Layout and Calculated Lengths Yellow – Parks original estimate Gray – As collected Blue – Manually and generalized Red – Final Trail

11. Further Improvements More data collection Greater input from park staff, users – What information is important? Run trial/test before main collection Use other methods to calculate distance – Bicycle or human pedometer, measuring wheel Publish data to users in easy to use format – Web, Google Earth, Paper Maps

12. Google Earth Test Arcmap 9.2 has *.kml output Other applications can do this too Small file size, easily shared and used Built in topo features Overlay with other data

13. Sources and Credits LRRP Staff and data Trimble Geog594 Class