Post on 18-Jan-2016
description
FUNDAMENTALS OFGEOGRAPHIC DATA
James STEWARTMEASURE Evaluation
15 février 2010
Suivi et Evaluation des programmes VIH/SIDA- Séminaire régional CESAG - Dakar, Sénégal
MEASURE Evaluation is funded by USAID through
Cooperative Agreement GHA-A-00-08-00003-00 and is
implemented by the Carolina Population Center at the
University of North Carolina at Chapel Hill, in partnership with
Futures Group International, John Snow, Inc., Macro
International Inc., Management Sciences for Health, and
Tulane University. The views expressed in this publication do
not necessarily reflect the views of USAID or the United States
government.
Visitez-nous en ligne à http://www.cpc.unc.edu/measure.
General Objective
The general objective of the module
« Fundamentals of Geographic Data » is to present
the fundamentals of geographic data, including the
relationship between geographic and attribute data,
and to help participants understand some important
data quality considerations.
Session Plan
Coordinate systems and datums
Geographic data
Geographic identifiers
Data schema best practices
GeographicIdentifiers
Geographic Identifiers
GPS coordinate
Administrative name
In reference to other features
Geography basics
Latitude/Longitude
Taj Mahal: 27.17 Latitude 78.04 Longitude
GPS Coordinate
Global
Positioning
System
GPS Coordinates
Advantages Very accurate:
10 meters or less
Easy to get a quick location of a few objects
Receivers and devices becoming more affordable
Disadvantages If many objects need to
be located, there needs to be a well designed data collection protocol
Capturing something other than a point can add time and cost
GPS Coordinate
Best practice: Display as
latitude/longitude coordinate
Example:
36.05576
078.91376
Geographic Identifiers
Administrative division names or codes Regions, provinces, districts, communes
Human settlement names or codes
Cities, villages, neighborhoods, informal settlements
Exact locations
Street addresses, GPS coordinates
Geographic Identifiers: Administrative Divisions
Source: Odhiambo, Emma. “Census Cartography: The Kenyan Experience,” presented at the United Nations Expert Group Meeting on Contemporary Practices in Census Mapping and Use of
Geographical Information Systems, 29th May – 1st June 2007, New York.
Kenyan Geographic Hierarchy for 1999 Census
Acknowledgments:USAID, FEWS, EDC-International Program, andthe U.S. Geological Survey.
Source:Administrative boundaries downloadedOctober 2008 from http://gisweb.ciat.cgiar.org/povertymapping/.
Geographic Identifiers:Human Settlements
Cities
Towns
Villages
Neighborhoods
Communities
Informal settlements
Geographic Identifiers
Anything that helps uniquely identify where something is
Data SchemaBest Practices
Data Schema Best Practices:Data Dictionary
Data Schema Best Practices:Data Dictionary
Data Schema Best Practices:Data Dictionary
Data Schema Best Practices:Data Dictionary
Data Schema Best Practices:Example
Data Schema Best Practices:Example
Data Schema Best Practices:Example
Data Schema Best Practices:Summary
Use a data dictionary
Always include geographic identifiers
Require one record per row, one value per cell
Avoid missing values
Data Schema Best Practices:Summary
Related Assumptions
Data stored in electronic format
Paper-based records inhibit analysis
Data stored in spreadsheet or database
Word processing and PDF documents inhibit analysis
Data Schema Best Practices:Summary
Good Data Schema
Results in higher quality data
Facilitates linking and sharing of data
Strengthens the data infrastructure
Improves the decision-making process
MERCI
Discussion Questions
What geographic identifiers do you use in your country, and do they work well for the types of decisions you need to make?
What problems have you run into, if any?
Do you always include these geographic identifiers in your data?