1. Christopher R. Bennett EASTR
GIS Data Collection
Christopher R. Bennett
EASTR

2. Overview of Presentation
Introduction
Spatial Data
Options for Collecting GPS Data
Examples of Output 2

3. Introduction

4. Background to Project Sponsored by EAP Innovation Fund
$30k to investigate spatial tools for project preparation and supervision
Project looked at
Opportunities for spatial data on projects
Data collection techniques
Ways of managing data 4

5. Findings Project completed January 2006
Recommended EAP commit to using spatial data on projects
Proposed:
Using GPS Enabled Camera to collect data
Google Earth to manage data 5

6. Spatial Data

7. Spatial Referencing
Any location can be expressed as the latitude and longitude
A unique and permanent way of identifying location 7

8. Types of Data Vector Raster
Points, lines (two or more points) and polygons (multiple lines)
Each point is represented by (x,y) co-ordinates corresponding to latitude and longitude
Raster
Usually images 8

9. Ways of Collecting Data
GPS Surveys
Data collected using Global Positioning System (GPS)
GPS uses satellites and triangulation to get the location
Digitizing
Existing maps are converted to digital
Aerial Photos and Satellites 9

10. Principles of GPS Measurement
Run by US Department of Defense
24 satellites at 20,200 km altitude
Normally 5 satellites can be viewed anywhere in the earth
Satellite sends a radio timing signal
Time measurements used to establish distance from satellite 10

11. GPS Locations
By observing a minimum of 4 satellites (3 position; 1 for time) location can be established
More satellites in view gives better accuracy 11

12. GPS Accuracy Depends on
The number of satellites in view
The equipment
Typical consumer equipment +/- 8 – 10m with 95% confidence
Survey grade instruments +/- 2 m or better
Accuracy improved by:
Differential correction
Signal from GPS base station or similar 12

13. Example of GPS Accuracy
Uncorrected: +/- 1.2 – 6.3 m; Corrected: +/- 1.1 – 1.6 m 13

14. Example of GPS Accuracy - Apia14

15. Options for Collecting GPS Data

16. Overview Project field tested different equipment
Handheld GPS receiver
Personal digital assistant
GPS enabled camera
All were found to be suitable for us 16

17. Data Needs
GPS data
Point data: data at a single location (x,y)
Continuous data: set of (x,y) data representing a line (eg road)
Most preparation and supervision projects need point data
Spatially referenced digital photographs valuable 17

18. Data Definitions
Area
Issue
Safeguards – Environment (SE)
Air Pollution
Dust Pollution
Noise Pollution
Property/Land Damage
Water Pollution
Other
Safeguards – Resettlement (SR)
Compensation Level
Completion of House Demolition
Completion of Land Acquisition
Property Replacement
Engineering (E)
Construction Quality
Design Issue
Safety Issue
Inventory (I)
Clinic/Hospital
Casting Yard
Construction Camp
Materials Storage
School
Important to ensure consistency when defining what data collected
Identified simple codes for range of issues 18

19. Handheld GPS Receivers
Many different types available
Consumer models cost < $200
Project use Garmin e-Trex
Garmin most widely supported by 3rd party software
Can store about 10,000 points
12 channels so should give good accuracy 19

20. Garmin Findings
Robust unit with good battery life (17 h for 2 x AA batteries)
Very simple to use in the field
For continuous data travel to site and turn on
Useful to have windscreen mount for unit
Not easy to enter point data description 20

21. Personal Digital Assistants (PDAs)
Tested Windows based PDA with CF-Card GPS
Data Collected with:
Custom software
Data Logging
GPS2Googe Earth 21

22. PDA - Pocket PC Creations
Software designed for rapid development
Data ported to access
Good for proof-of-concept
Several problems:
Was not able to collect continuous data
Difficult to install
Expensive to deploy 22

23. PDA - GPS Data Logging Many applications store GPS data Simple to use:
Turn on GPS
Software logs data
Only disadvantage was inability to store point data 23

24. PDA - GPS2Google Earth Low cost (<$20)
Simple application to record point and continuous data and export GE files
Simple to use and with some refinements ideal for Bank data collection 24

25. Digital Photographs and GPS
Digital photos (.JPG files) can have spatial co-ordinates added to header
When read into GIS/GE image correctly postioned.
Two options
Link digital photos to GPS log data
GPS enabled camera 25

26. Digital Photos – Linking To GPS
Time of photo matched to GPS log data
Used Robogeo (v 3) ($50) software
After GPS data matched created GE file 26

27. Robogeo Matching 27

28. Digital Photos – GPS Camera
Camera with embedded GPS records spatial data along with photo
Very easy to use
Project tested Ricoh Pro-G3
More details in next presentation 28

29. Examples of Outputs

30. Comparison of 3 Devices
Recorded data in same location with Handheld GPS, PDA and GPS Camera
Excellent agreement 30

31. Shiman Highway Project – 131

32. Shiman Highway Project - 232

33. Shiman Highway Project - 333

34. Cambodia GIS Import 34

35. Thailand GPS Image 35

36. Satellite Image 36

37. For More Details
Download the report ‘Using Google Earth on World Bank Projects’ from 37

38. The End