Multiple Indicator Cluster Surveys
Survey Design Workshop
Using GPS to collect cluster
locations
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What is GPS
• GPS is a satellite-based navigation system
• A GPS unit determines its position using satellites that
orbit the earth. Each satellite’s position, as well as the
current time, is transmitted via radio signals. The GPS
unit receives these signals and uses them to calculate
its position in terms of latitude, longitude, and altitude
• There is a variety of GPS brands and models
• Recommended model for use in MICS surveys is
GARMIN ETREX GPS
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Why use GPS to collect cluster locations
• Permits linking of additional data to MICS data
through geographic links
– E.g. Census data, facility data, other geo-located
data
• Permits geographic grouping of data beyond
region
– E.g. Climactic zones, agricultural zones, etc.
• Permits mapping of sample clusters
– E.g. with DevInfo
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Examples of what GPS data can bring to MICS
Source: DHS studies
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Decision Process for GPS Data Collection
Method
• Using pre-existing GPS data
– Ex. using Geo-referenced Census
– GPS coordinates can be acquired before
the survey or listing (after EA selection)
• Collection of GPS during listing
– If not talk to the survey manager to discuss
possible options (strong recommendation to
collect GPS data during listing activities)
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GPS Collection Process
1.
2.
3.
4.
The GPS collection teams collect one waypoint
(location) for each assigned cluster
The waypoints are captured as close to the
geographic center of the cluster as possible
Saved information are waypoint name (cluster
number), latitude, longitude, and altitude to the GPS
unit
These information should also be written down on
GPS form that will serve as a paper back-up if any
digital data in the GPS unit is lost or corrupted
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GPS Collection Teams
1. GPS data collection may be incorporated
into different phases of survey:
•
If the GPS units are used to update the sample
frame, then listing teams are responsible for
collecting the GPS data
•
GPS data collection may also take place during
interviews, in which case one person on a team
may be responsible for collecting the GPS
waypoints
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How to use GPS
1. Finding a “Good” Location to Collect a GPS
Waypoint
2. Activate GPS
3. Identify and mark location (“waypoint”)
4. Record location on form
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1. Finding a “Good” Location to Collect a GPS
Waypoint
• Find a place with a clear unobstructed view of
the sky
– First Choice: Geographic center of the populated
settlement area of the cluster
– Second Choice: Open area near the center, or on
top of a building in the center
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2. Activate Garmin
• Turn on the Garmin. Once it has locked into
enough satellites then press the Page button
until you reach the MENU screen and select
MARK.
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3. Assign Cluster Number
• Highlight the Waypoint ID
• Enter in the Cluster Number
Waypoint ID
Coordinate
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4. Complete GPS Form
• Complete the GPS Form
• Highlight OK and click Enter
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GEOGRAPHIC POSITIONING SYSTEM FORM
GP
GP1. Cluster number:
___ ___ ___
GP2. Area:
Urban
Rural
Example
of Log
Sheet
GP3. Region:
Region 1
Region 2
Region 3
Region 4
1
2
1
2
3
4
GP4. Operator name and number:
Name
___ ___
GP5. Day/Month/Year of
measurement:
___ ___ / ___ ___ / ___ ___ ___ ___
Checked estimated accuracy (after “ready to navigate”)
Marked Waypoint
Renamed Waypoint to cluster number
Recorded Waypoint’s position
Saved Waypoint
GP6. Waypoint name:
___ ___ ___ ___ ___ ___
N/S/E/W
Degrees
Decimal degrees
GP7. Latitude:
N S
___ ___ . ___ ___ ___ ___ ___
GP8. Longitude:
E W
___ ___ ___ . ___ ___ ___ ___ ___
GP9. Altitude:
Elevation (Meters) ___ ___ ___ . ___ ___ __
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Post Field GPS data checking and cleaning
•
•
When GPS data return from field work, the
GPS Data Collection Coordinator checks
that the GPS data are correct
S/he uses GPS TrackMaker1, a free
geographic information system, to plot the
GPS points and check for common errors
The GPS TrackMaker® program for Windows® 98SE/2000/ME/XP/Vista
allows bi-directional datacommunications between GPS receivers and your
computer, including full data editing and storage options
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Common errors in the GPS data
•
Duplicate or Paired Points
•
Missing Data
•
Administrative Mismatches
•
Hand-Entry Typos
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With thanks to
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