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GTECH 361
Lecture 07
Secondary Data
Geodatabase Topology
Rule-based
Geometric Networks
Editing With Topology
Relationship Classes
Types of Geodatabases
Personal GDB
Enterprise GDB
Inside the Geodatabase
Now to the Session Proper
Secondary data sources
US Census
Geo data portal
Why Secondary Data?
Context (geographic, temporal, social) for primary data
Secondary data may provide validation for primary data
Secondary data may act as a substitute for primary data
Unofficial Secondary Data Sources
Private research results Research reports, research papers,
textbooks Opinion polls Market research On-line databases Anecdotal/hearsay
Official Secondary Data Sources
Agriculture Business/
Industry Crime Education Finance
Energy Environment Health Transport Weather
Agriculture
USDA
FAO
Farm Bureau Federation
Babcock
Business / Industry
STAT-USA/Internet (US Dep. of Commerce, not free)
Consumer Expenditure Surveys(Bureau of Labor Statistics)
Internal Revenue Service
Crime
Bureau of Justice Statistics
FBI
Crime & Justice Electronic Data Abstractshttp://www.ojp.usdoj.gov/bjs/dtdata.htm
Education
National Center for Education Statistics
School District Data Book (ORST)
National Science Foundation
UNESCO
Environment EPA Envirofacts EPA EnviroMapper
Facility Information Hazardous Waste Data Superfund Toxics Releases Inventory Water Discharge Permits
ScoreCard Right To Know
Health
National Center for Health Statistics (CDC)
Social Security Administration
Geophysical
NOAA
USGS
US Forest Service
Soil Conservation Service
Dep. of Natural Resources (DNR)
Dep. of Conservation
Transportation
Department of Transportation
Bureau of Transportation Statistics
State Highway Departments (CA, TX)
Regional Transport Authorities
Census Structure Timing Population Organization Analysis Presentation Geographical Hierarchy Variables
Historical Context
Article I, Section 2 of the U.S. Constitution adopted in 1787 approved that Representatives and Taxes shall be apportioned among the states according to each states population.
Enumeration (to ascertain the number of: count) shall be made within every subsequent term of 10 years
The first Census of Population was conducted in 1790, it counted 3.9 million people and increased representation in the House to 105.
As the Nation’s needs and interests became more complex statistics were added to help people understand what the raw numbers meant.
Historical Context
What is Collected? In 1954 Title 13 of the United States
Code brought together the laws under which the Census Bureau operates
This included a law requiring the following Censuses to be conducted:
Population, housing, manufacturers, mineral industries, other businesses, construction, transportation, and governments at stated intervals
Confidentiality The sole purpose of the censuses is to
secure general statistical information. Replies are obtained from individuals and establishments only to enable the compilation of these general statistics
By law, no one is permitted to reveal identifiable information
Before any information is published it is checked to make certain that no individual, household or organization can be identified
The individual forms filled out are closed to public viewing for 72 years
The Freedom of Information Act does not apply to identifiable census data
Confidentiality
Census 2000 Forms
2 main types, a short form and a long form The short form asks 7 questions 83% of households received the short form The long form covers 34 subjects 1 in 6 households received the long form The long form took approximately 38(?!)
minutes to complete
Why Two Forms? The short form The long form The data from the long form is
considered to be representative of all the people in the “neighborhood” and is extrapolated into sample data
The data from the short form is considered to count 100% of the population
Dealing with Census Data
The main way to tackle census data is by: Geographic extent of the area you are
interested in and Variables or subjects The key is to combine the two
Census Geography
It is confusing!
Changes over time
Some levels are based on population numbers
Do not compare oranges to apples!!
Census Geographic Areas
States, DC and Puerto Rico Counties Cities, towns, and townships Census tracts (roughly 4000 people,
neighborhood sized areas) Block groups (groups of census blocks,
generally containing 800 to 1,000 people) Blocks (9 million, covering entire US, not
all data is summarized to this level) Congressional districts American Indian and Alaska Native Areas
Census Geographical Hierarchy
Metropolitan Areas
Census Geography It is confusing! Changes over time Some levels are
based on population numbers
Do not compare oranges to apples!!
Census Household Variables
Number of persons Age and gender Race Language Income and
poverty Education Employment Citizenship
Vehicles for commute Disability Homeownership status Vacancy Rent and value of
housing Age and type of
structure Plumbing and Kitchen Heating
Examples of Census Variables
Accommodations Agriculture Alaska Natives Arts,
Entertainments Asians Assets Assistance
Capital Expenditures
Child Care/Support Commodity Flows Communications Consumer Income County Business
Patterns County/City
Government
The Concept of Race Not based on any scientific definition Prior to Census 2000 only allowed 1 choice Census 2000 allowed the following choices
for Race: White Black, African American American Indian or Alaska Native (tribe was
requested) Asian Indian, Japanese, Chinese, Filipino, Hawaiian,
Korean, Vietnamese, Guamanian or Chamorro Samoan Or to be written in if none of these apply
Ethnic Origin The Hispanic population is considered
an ethnic group according the the Census Bureau In Census 2000 choices for Hispanic origin
or descent were: Mexican Mexican American Puerto Rican Cuban Or Other Spanish/Hispanic/Latino
The concept of race separate from Hispanic origin has been confusing Census users for years
The thing to remember is that while a person may be of Hispanic origin, they also are white, black, asian-pacific islander, or other
It’s the same concept of being white and of german ethnicity
Race/Ethnic Origin
Multiracial Categories Controversy
Until 1970 the Census Bureau enumerator decided people’s race for them, sometimes by inquiring, often by simply looking
Since 1970 people could choose only 1 race to describe themselves
Census 2000 allowed people to choose any number of races
Over 7 million people marked more than one race to describe themselves
This number is less than 3 percent of the total population but has huge impacts in a number of ways
If one counts only those who checked American Indian alone, 2.5 million
If one counts those whites and blacks who think they have a little Indian blood, and checked it in addition to white or black categories, 4.1 million
That is an increase of nearly 65% Should the Federal Government
increase services for Native Americans by 65%?
Native Americans
Statistical Problems
The Census Bureau’s racial percentages now add up to well over 100
No one can reliably compare 1990 or earlier data to 2000 data
TIGER Topologically Integrated Geographic
Encoding and Referencing system
Based on USGS topographic maps but majorly augmented
Contains no elevation data
No copyright
No attribute data!
American Community Survey
Annual
Long
Representative – not comprehensive
Master Address File for sample selection
Wisconsin a forerunner
Pro’s and Con’s of Secondary Data
Advantages Cheap Timeliness Access to
people/organizations that we wouldn’t have access to otherwise
Less post-processing
Disadvantages
Collection method unknown
Lack of control
Geoinformation Portals
Public data (mostly federal)
http://www.geodata.gov/
Public and private data (sometimes
costly)
http://www.geographynetwork.com/
Data Vendors
Remote Sensing Value adding to public data Utilities Market Research GIS Vendors University Extensions World Bank
Before YOU Purchase Data
Accuracy
Compatibility
Lineage and metadata
Who owns the copyright?