mable/geocorr (2k version) john blodgett oseda missouri census data center rev. 12/06

MABLE/GeocorrMABLE/Geocorr(2k version)(2k version)

John Blodgett John Blodgett OSEDAOSEDA

Missouri Census Data CenterMissouri Census Data Center

Rev. 12/06Rev. 12/06

Prepared by: The Office of Social and Economic Data Analysis,University of Missouri Extension in Conjunction with the Missouri Secretary of State and the Missouri State Library

What Is MABLE/Geocorr?What Is MABLE/Geocorr?

Geocorr is a web Geocorr is a web application that accesses application that accesses the MABLE geographic the MABLE geographic database.database.

A geographic utility that A geographic utility that reveals relationships reveals relationships between geographic between geographic layers.layers.

Works for the Works for the entire entire U.S.U.S. with emphasis on with emphasis on Census geography. Census geography.


How Can I Access the Application?How Can I Access the Application?

http://mcdc2.missouri.edu/websas/geocorr2k.htmlhttp://mcdc2.missouri.edu/websas/geocorr2k.html

Linked to within the Linked to within the Quick LinksQuick Links navigation box on navigation box on most most Missouri Census Data CenterMissouri Census Data Center (MCDC) web site (MCDC) web site pages. pages.

This is the current version with 2000 census This is the current version with 2000 census geography. An earlier version with 1990 geography is geography. An earlier version with 1990 geography is linked to (as “Previous Version”). linked to (as “Previous Version”).


Quick Example 1Quick Example 1We are interested in the relationship of the We are interested in the relationship of the 2 geographic layers: county and Urban-2 geographic layers: county and Urban-Rural portion. Rural portion.

For each county in a state we want to For each county in a state we want to know how much of the county is urban vs. know how much of the county is urban vs. rural. rural.

We select our state and our two We select our state and our two geographic layers--3 clicks. Then geographic layers--3 clicks. Then submitsubmit..


Quick Example 1: Output Quick Example 1: Output


Reading the OutputReading the Output

CountyCounty is the chosen is the chosen Source geocode; Source geocode; urur is the chosen is the chosen Target geocodeTarget geocode..

The source area (Fairfield co.) intersects with 2 target The source area (Fairfield co.) intersects with 2 target areas – hence 2 lines in the report.areas – hence 2 lines in the report.

36,195 people in the county also lived in a block 36,195 people in the county also lived in a block designated “rural” in 2k census. 4.1%.designated “rural” in 2k census. 4.1%.

The other 846,372 residents lived in urban areas. 95.9%The other 846,372 residents lived in urban areas. 95.9%


Quick Example 2Quick Example 2A bit more complicated, but still fairly A bit more complicated, but still fairly simple.simple.

Choose Choose 2000 census tract2000 census tract as Source geo as Source geo and and 2000 PUMA2000 PUMA (for 5 Pct Samples) as (for 5 Pct Samples) as target geo.target geo.

Use Use Geographic Filtering Options Geographic Filtering Options section to limit processing to 1 county.section to limit processing to 1 county.

Output to csv file (comma delimited) which Output to csv file (comma delimited) which IE automatically imports into Excel.IE automatically imports into Excel.


Quick Example 2: Excel OutputQuick Example 2: Excel Output


Quick Example 2: NotesQuick Example 2: NotesWe chose Missouri for state. Then in the We chose Missouri for state. Then in the Geographic Filtering OptionsGeographic Filtering Options section we section we entered a single county code value in the text entered a single county code value in the text box provided for doing such filters.box provided for doing such filters.

There is a link to There is a link to County codesCounty codes on the form on the form that we could use if we did not know the code. that we could use if we did not know the code. We typed in We typed in 2918329183 for St Charles (MO). for St Charles (MO).

We hid the columns County & Cntyname in the We hid the columns County & Cntyname in the spreadsheet because they were constants.spreadsheet because they were constants.


Uses of “Correlation Lists”Uses of “Correlation Lists”

Geocorr outputs are called “correlation lists”, Geocorr outputs are called “correlation lists”, “equivalency files”, “crosswalk files”, etc. “equivalency files”, “crosswalk files”, etc.

They have many uses. Such as:They have many uses. Such as: Create new map coverages using a GIS with Create new map coverages using a GIS with

“geographic dissolve” function. E. g. tag tracts with “geographic dissolve” function. E. g. tag tracts with PUMA codes and create a PUMA layer from a tract PUMA codes and create a PUMA layer from a tract layer.layer.

Select all ZIP codes (or counties) that are all or mostly Select all ZIP codes (or counties) that are all or mostly rural.rural.

See which counties comprise a metro area.See which counties comprise a metro area.


Geocorr2k Input formGeocorr2k Input form

Has never won any awards for style.Has never won any awards for style.

Appears more daunting than it really is.Appears more daunting than it really is.

Has 5 major sections, not counting the Has 5 major sections, not counting the very top (“top matter”) and bottom.very top (“top matter”) and bottom.

Of the 5 sections, the last 2 are rarely Of the 5 sections, the last 2 are rarely used and the 3used and the 3rdrd only occasionally. only occasionally.

Most options have default values that Most options have default values that rarely need to be modified. rarely need to be modified.


Geocorr2k Input Form: ”Top Matter”Geocorr2k Input Form: ”Top Matter”

Identifies the application, incl version and Identifies the application, incl version and revision date.revision date.

Links to related applications:Links to related applications: Previous VersionPrevious Version link takes you to version link takes you to version

with 1990’s-era geography. with 1990’s-era geography. CCCCCC link lets you look up geocodes for use in link lets you look up geocodes for use in

Geographic Filter section.Geographic Filter section. Direct access mable2kDirect access mable2k link is for power link is for power

users who are willing/able to access the data users who are willing/able to access the data without the geocorr interface. without the geocorr interface.


Help and ExamplesHelp and Examples

These 2 links near the top of the page take you These 2 links near the top of the page take you to web pages that were created in the late 90’s.to web pages that were created in the late 90’s.

A few details have changed since these were A few details have changed since these were written, but they are still very useful documents. written, but they are still very useful documents.

Where things have changed it’s pretty obvious.Where things have changed it’s pretty obvious. We strongly suggest you read these two pages.We strongly suggest you read these two pages.


Five Main Sections…Five Main Sections…

““Only the first 2 are required” it tells us at Only the first 2 are required” it tells us at the top of the page.the top of the page.

The row of links across the top take you The row of links across the top take you directly to each section.directly to each section.

The “Bounding Box” section, in particular, The “Bounding Box” section, in particular, is rarely used. is rarely used.


Input OptionsInput Options Section Section

By far the most important section of the By far the most important section of the form.form.

Choose the state(s) of interest. You can Choose the state(s) of interest. You can choose all 51 but you run the risk of timing choose all 51 but you run the risk of timing out.out.

Note the Note the MAGGOTMAGGOT link just above the link just above the geocode select lists.geocode select lists.


Input OptionsInput Options – 2 – 2

Select “1 or more” geocodes from the 2 Select “1 or more” geocodes from the 2 select lists (“Source” and “Target”). select lists (“Source” and “Target”).

Selecting more than 1 geocode from a list Selecting more than 1 geocode from a list creates a composite layer. creates a composite layer.

Parent geocodes are selected Parent geocodes are selected automatically for you. E.g. selecting tract automatically for you. E.g. selecting tract automatically selects county; selecting automatically selects county; selecting place automatically selects state. place automatically selects state.


Input OptionsInput Options - 3 - 3

Entire Universe [no code]Entire Universe [no code] selection a selection a special case. special case.

Use it, for example, to just get a list of the Use it, for example, to just get a list of the codes and names of all the [counties or codes and names of all the [counties or places or CBSAs, etc] for the selected places or CBSAs, etc] for the selected geographic universe. geographic universe.

--Missouri-only geocodes----Missouri-only geocodes-- :the codes in :the codes in this section are only available for Mo.this section are only available for Mo.


Input OptionsInput Options - 4 - 4

The weighting variable is what geocorr uses to The weighting variable is what geocorr uses to measure the size of the intersection between the measure the size of the intersection between the base/target layers. By default we use 2k census base/target layers. By default we use 2k census pop.pop.

The option to “ignore Census Blocks with a The option to “ignore Census Blocks with a value of 0 for the weighting variable” saves value of 0 for the weighting variable” saves some processing time. Avoids “trivial sliver” some processing time. Avoids “trivial sliver” intersections. E.g. where 2 areas share some intersections. E.g. where 2 areas share some common space, but nobody lives in that space. common space, but nobody lives in that space.


Output OptionsOutput Options Section SectionThe “The “weighted centroidsweighted centroids” option says to take a ” option says to take a weighted average (using the chosen weight weighted average (using the chosen weight variable) of the lat-long coordinates of each variable) of the lat-long coordinates of each census block contained in an output geographic census block contained in an output geographic area. Not widely used.area. Not widely used.

Generate 2Generate 2ndnd allocation factor allocation factor option is handy. option is handy. For example, if you did a ZIP to Place (city) list For example, if you did a ZIP to Place (city) list with pop2k as weight you could tell what portion with pop2k as weight you could tell what portion of the ZIP was in the city of the ZIP was in the city andand what portion of the what portion of the city was in the ZIP. city was in the ZIP.


Output OptionsOutput Options - 2 - 2

Sort by target geocodesSort by target geocodes lets you lets you override the default sort order of outputs. override the default sort order of outputs. You can accomplish this by just reversing You can accomplish this by just reversing the choices of source vs. target geocodes the choices of source vs. target geocodes – but then the allocation factors would be – but then the allocation factors would be different. different. Think of a ZIP to CD list that you want Think of a ZIP to CD list that you want organized (sorted) by CD but you want to organized (sorted) by CD but you want to know what know what portionportion of each ZIP is in the of each ZIP is in the CD.CD.



You can (de)select the option to output a You can (de)select the option to output a delimited file. You can also select to have tabs delimited file. You can also select to have tabs instead of commas as the delimiter between instead of commas as the delimiter between fields. (Not recommended if you to import into fields. (Not recommended if you to import into Excel.) Excel.)

You can (de)select to have a listing file output. You can (de)select to have a listing file output. You have a small pull-down to choose listing You have a small pull-down to choose listing format: plain txt, html, pdf.format: plain txt, html, pdf.

For both output types (csv/listing) you can opt to For both output types (csv/listing) you can opt to not keep codes or names associated with codes.not keep codes or names associated with codes.



The final option in this section allows specifying The final option in this section allows specifying a title for your output report. (Avoid using special a title for your output report. (Avoid using special characters such as characters such as && and and %% in this title) in this title)

Finally, we see our first pair of Finally, we see our first pair of Reset Defaults/Run Reset Defaults/Run RequestRequest buttons. It is quite common for your buttons. It is quite common for your request to be completed at this point with request to be completed at this point with nothing specified in the last 3 sections.nothing specified in the last 3 sections.

Nothing really happens until you click a Nothing really happens until you click a Run Run RequestRequest button. button.


Exercise Exercise

Generate a report showing what cities Generate a report showing what cities (places) correspond to what ZIP codes (places) correspond to what ZIP codes (ZCTA’s) in your state.(ZCTA’s) in your state.

The report should be sorted by place and The report should be sorted by place and should indicate both what portion of the should indicate both what portion of the place population is in the ZIP and what place population is in the ZIP and what portion of the ZIP population is in the portion of the ZIP population is in the place.place.


Typical Output, this ExerciseTypical Output, this Exercise


Exercise VariationsExercise Variations

Modify your report as followsModify your report as follows Select County as a Source geocode (in Select County as a Source geocode (in

addition to place)addition to place) Drop the 2Drop the 2ndnd allocation factor option. allocation factor option. Request your report in HTML format.Request your report in HTML format. Use Use Geographic Filtering OptionsGeographic Filtering Options section of the section of the

form to filter based on place code: enter a form to filter based on place code: enter a value of value of “-9999“-9999” to indicate you want to ignore ” to indicate you want to ignore “unincorporated remainder” areas. “unincorporated remainder” areas.


Exercise-With-Variations: OutputExercise-With-Variations: Output


The MABLE DatabaseThe MABLE DatabaseThe underlying database for the The underlying database for the application is the application is the Master Area Block Level Master Area Block Level

EquivalencyEquivalency file. file.

It’s a collection of state-based tables. Each It’s a collection of state-based tables. Each row of these tables describes a small unit row of these tables describes a small unit of geography – a 2000 of geography – a 2000 census blockcensus block..

The columns of these tables are The columns of these tables are geographic codes or attributes.geographic codes or attributes.


The geocorr2k Geographic UniverseThe geocorr2k Geographic Universe

Starts with a choice of state(s), 1Starts with a choice of state(s), 1stst thing. thing. Each of last 3 sections have to do with Each of last 3 sections have to do with specifying within-state limits to the specifying within-state limits to the “GU“GU”.”.You can limit the GU to specified (1 or You can limit the GU to specified (1 or more) counties, places, ma’s, UA’s, or more) counties, places, ma’s, UA’s, or places (“geographic filters”).places (“geographic filters”).Last section allows filtering using a Last section allows filtering using a “bounding box”. “bounding box”. Each block in MABLE has a lat-long Each block in MABLE has a lat-long internal point. Blocks are spatially filtered internal point. Blocks are spatially filtered using that point. using that point.


Point and Distance OptionsPoint and Distance Options

Allows limiting the GU to a circular area.Allows limiting the GU to a circular area.

Allows defining multiple “ring” areas in Allows defining multiple “ring” areas in addition to limiting GU (to largest ring).addition to limiting GU (to largest ring).

User needs to specify latitude-longitude User needs to specify latitude-longitude coordinates. (coordinates. (linkslinks to web pages given). to web pages given).

The GU is limited to blocks with int pts The GU is limited to blocks with int pts within within RadiusRadius miles of ( miles of (lat,longlat,long), where …), where …


Radius and (lat,long)Radius and (lat,long)

Radius is the value entered in the 1Radius is the value entered in the 1stst text box text box (“(“Value for radius of Circle or radius of largest RingValue for radius of Circle or radius of largest Ring:”).:”).

Lat, long are the values entered in the 2 Lat, long are the values entered in the 2 boxes on the “boxes on the “Coordinates of PointCoordinates of Point:” line. :” line.

Enter lat/long values in decimal degrees.Enter lat/long values in decimal degrees.

Use the Use the Melissa linkMelissa link to enter a street address to enter a street address and get lat/long coordinates. (right click).and get lat/long coordinates. (right click).


Sample Melissa Geocoding ResultsSample Melissa Geocoding Results

Latitude & longitude coordinates in decimal Latitude & longitude coordinates in decimal degrees are on the next to last line shown here. degrees are on the next to last line shown here.

Use copy / paste to insert these values into the Use copy / paste to insert these values into the geocorr2k form. (assumes 2 browser windows).geocorr2k form. (assumes 2 browser windows).


Specifying a 5-Mile Radius of AddressSpecifying a 5-Mile Radius of Address

Partial view of the section with Radius value Partial view of the section with Radius value specified as 5, and with the coordinate values as specified as 5, and with the coordinate values as obtained via the Melissa geocoding link. obtained via the Melissa geocoding link. The The Label of PointLabel of Point value is strictly optional. value is strictly optional. West longitude assumed. Entering a leading “-” West longitude assumed. Entering a leading “-” would make no difference – it is would make no difference – it is assumedassumed..


Complete Specs to Go With These Complete Specs to Go With These Point and Distance OptionsPoint and Distance Options

Choose Missouri as state (default).Choose Missouri as state (default).

Choose County as Source geocode.Choose County as Source geocode.

Choose Entire Universe as Target geo.Choose Entire Universe as Target geo.

Choose HTML format for output report.Choose HTML format for output report.

Specify a custom title. Specify a custom title.

Point and distance options per previous Point and distance options per previous slide with no further entries in that section.slide with no further entries in that section.


Which Generates ThisWhich Generates This

It generates a 1-line report because the entire 5-It generates a 1-line report because the entire 5-mile circular area is entirely within Boone county.mile circular area is entirely within Boone county.The sum of the weights gives you the total pop The sum of the weights gives you the total pop (2000) within the 5-mile circle. (2000) within the 5-mile circle. The Distance and weighted centroid coords are The Distance and weighted centroid coords are automatically added when a pt is specified. automatically added when a pt is specified. The label of the Distance variable uses the The label of the Distance variable uses the “Label of point” value we entered. “Label of point” value we entered.


Same Specs Except for…Same Specs Except for…Use your browser Back button to return to Use your browser Back button to return to the specs just entered. Make these the specs just entered. Make these changes:changes: Change the value for Radius from 5 to Change the value for Radius from 5 to 50.. Further down in the Point-and-Distance Further down in the Point-and-Distance

section enter a value of section enter a value of 5 as the “# of equi- as the “# of equi-distant rings”.distant rings”.

Change Target geo selection to Change Target geo selection to Concentric Ring Pseudo-Geocode

Edit the title. Edit the title.


Ring Pseudo-Geocodes (“RPG”s)Ring Pseudo-Geocodes (“RPG”s)

These are dynamically-generated geographic These are dynamically-generated geographic areas. The first one generated is a circular area areas. The first one generated is a circular area centered at the specified point with a radius of centered at the specified point with a radius of the first specified ring value. the first specified ring value. Any subsequent RPG is a ring (i.e. Any subsequent RPG is a ring (i.e. donutdonut) with ) with an outer radius of ring N and inner radius of ring an outer radius of ring N and inner radius of ring (N-1). (N-1). Ring values are entered manually (in pt-and-Ring values are entered manually (in pt-and-distance section) or using Radius and # of equi-distance section) or using Radius and # of equi-distant rings (as in our example). distant rings (as in our example). A maximum of 10 RPGs may be generated.A maximum of 10 RPGs may be generated.


Output From Revised Run with RPGsOutput From Revised Run with RPGsThe RPGs are labeled The RPGs are labeled with their outer radius with their outer radius values.values.16,431 people found in 16,431 people found in Audrain co between 20 Audrain co between 20 & 30 mi.& 30 mi.14,970 people found in 14,970 people found in Boone co in the 10-to-Boone co in the 10-to-20 mile “donut”.20 mile “donut”.Probably better to Probably better to switch Source & Target switch Source & Target geocodes here.geocodes here.


Exercises for the StudentExercises for the Student

1.1. (Use geocorr to) determine what portion of the (Use geocorr to) determine what portion of the land arealand area of North Carolina is rural. of North Carolina is rural.

2.2. Which unified school districts in New Jersey Which unified school districts in New Jersey cross county boundaries?cross county boundaries?

3.3. 63101 is the ZIP code for downtown St. Louis, 63101 is the ZIP code for downtown St. Louis, MO. What counties fall (all or partly) within a MO. What counties fall (all or partly) within a 50 mile radius of downtown St. Louis?50 mile radius of downtown St. Louis?

4.4. Generate a pdf report showing the counties Generate a pdf report showing the counties that comprise the Regional Planning that comprise the Regional Planning Commissions for the state of Missouri. Commissions for the state of Missouri.


Thank You!Thank You!

Address questions and comments to the Address questions and comments to the author at: author at:

[email protected]@missouri.edu

mable/geocorr (2k version) john blodgett oseda missouri census data center rev. 12/06

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