Transcript Document
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 Abstracts
http://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
Historical Context
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.
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
Confidentiality
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
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
Race/Ethnic Origin
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
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
Native Americans
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%?
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?