geocoding our nation's schools - blue raster nces stats-dc 2012 presentation
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GEOCODING OUR NATION’S SCHOOLS
Presented by Tai Phan & Adrienne AllegrettiNCES, Blue Raster
NCES STATS-DC 2012 – July 13, 2012
PRESENTATION OUTLINE
Introduction
Overview of Geocoding
Data Preparation
Selecting a Geocode Solution
Live Demonstration
Overview of SDDS Updates
Summary/Q & A
WHAT IS GEOCODING?
The process of finding associated geographic coordinates (latitude and longitude) from other geographic data, such as street addresses, or zip codes (postal codes).
HOW DOES GEOCODING WORK?
Address Interpolation:
HOW DOES GEOCODING WORK?
Other Techniques:
ADVANCEMENTS IN GEOCODING
THEN
ADVANCEMENTS IN GEOCODING
NOW
To support spatial analysis and provide geographic context to a schools location Geocoded schools can be overlaid with
other geographic layers such as: School Districts Locale Codes Counties Congressional Districts And more…
WHY DOES NCES GEOCODE SCHOOL ADDRESSES?
LOCATION MATTERS
HOW TO PREPARE DATA
Invest in your address data quality and check for errors before you begin: Spelling Numeric address ranges Missing information
Garbage In
Garbage Out
IMPLICATIONS OF GEOCODING ERRORS
Accuracy of geocoding dictates quality of research
Schools geocoded incorrectly can mean lost funding
Unable to respond to an emergency appropriately
HOW TO PREPARE DATA
Format it in a style that the geocoder can handleUse the locational address, not the PO Box or Administrative address of the school
HOW TO PREPARE DATA
Bad: FMLY CHLD CTR 1411 LNCLNWY W, MISHAWAKA, IN, 46544
HOW TO PREPARE DATA
Good: 1411 LINCOLN WAY WEST, MISHAWAKA, IN, 46544
SELECTING A GEOCODE SOLUTION
Things to consider: Budget Number of Records Infrastructure Number of Individuals Needing Access Frequency of Geocoding Sensitivity of Data
1ST APPROACH: LOCAL/INTERNAL
In House
Millions of
addresses
Economy of Scale
Datacenter and/or
Cloud Services
Sensitive Data
GEOCODING ON THE DESKTOP
Prerequisites ArcGIS Desktop Basic Prepared Address Table Reference Data (NAVTEQ, TOM TOM,
TIGER) Address Locator (Composite)
ON THE DESKTOP – COMPOSITE LOCATOR Multiple locators used in a cascading
fashionAddress
Match• Best
Match
Street Centroid Match
• Decent Match
Zip Code Match
• Acceptable Match
ON THE DESKTOP – USER INTERFACE
ON THE DESKTOP - OPTIONS
ON THE DESKTOP - OUTPUT
ON THE DESKTOP SUMMARY
Great way to go if software and reference data is already in-house
Can geocode more than 350,000 addresses per hour
Data maintenance and support No custom development required
2ND APPROACH: GEOCODING WEBSITES
Geocoding
Websites
Hundreds of
address at a time
Excel and Web Browser
Points on a Map
Publicly available
data
GEOCODING WEBSITES:
Single Address Look Ups: ArcGIS Online - http://
www.arcgis.com/home/webmap/viewer.html http://geocoder.us/ http://itouchmap.com/latlong.html https://webgis.usc.edu/Services/Geocode/Default.aspx
Batched or Multiple Address Look Ups: ArcGIS Online - http://
www.arcgis.com/home/webmap/viewer.html http://batchgeo.com/ http://www.gpsvisualizer.com/geocoder/
ARCGIS ONLINE – SINGLE ADDRESS
ARCGIS ONLINE – MULTIPLE ADDRESSES
ARCGIS ONLINE – MULTIPLE ADDRESSES
ARCGIS ONLINE – MULTIPLE ADDRESSES
3RD APPROACH: WEB APIS
Web
APIs
Hundreds to
Thousands of
addresses at a time
Publicly Accessibl
e DataCustom Development
Required
GEOCODING APIS AVAILABLE FOR CUSTOM DEVELOPMENT
ArcGIS Online Yahoo Bing Google MapQuest Geonames
Be sure to read the terms of service and know the limitations. For example, when using Google, you must display your results on a Google map. Google limits requests to 2,500 addresses, etc.
GEOCODE RESULTS
The Hit Rate is the number of addresses that are geocodable
The Match Scores tell you what level of accuracy a particular address was geocoded.
- Country- Region (state, province, prefecture, etc.)- Sub-region (county, municipality, etc.)- Town (city, village)- Post code (zip code)- Street- Intersection- Address
- Premise or Roof Top
HIT RATES AND MATCH SCORES
No Matches Found
HIT RATES AND MATCH SCORES
Zip Code Centroid
HIT RATES AND MATCH SCORES
Street Name Found
HIT RATES AND MATCH SCORES
Street Address Found
HIT RATES AND MATCH SCORES
Address Point Found (Highest Accuracy!)
OTHER OPTIONS - PLACEFINDERS
OTHER OPTIONS – REVERSE GEOCODING
DEMO – SDDS GEOCODING PROTOTYPE
WHAT ARE LOCALE CODES?
WHAT ARE LOCALE CODES?
Read more: http://nces.ed.gov/ccd/rural_locales.asp
SCHOOL BOUNDARY PROJECT
Project Background 350 largest districts already collected 1000+ collected by the end of the year
That’s over 50% of students
SCHOOL BOUNDARY PROJECT
Where to find the data
Can be downloaded from SDDS Standard Map Viewer.
WHAT’S NEW IN SDDS MAPVIEWER
Map Viewer Standard Census 2010 ACS 5yr Estimate
2006-2010 Public School
Boundaries Middle Elementary High
Promise Neighborhood Schools
Map Viewer Mobile Migration to
GEOCLOUDhttp://nces.ed.gov/surveys/sdds/index.aspx
Q & A
FOR MORE INFORMATION:
Adrienne [email protected]
703-842-0171
www.blueraster.comblog.blueraster.com
202-502-7431