[CTPP] Census Geography Question

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RE: [CTPP] Census Geography...

Ed Christopher

6 Dec 2011 6 Dec '11

7:44 p.m.

Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C)

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Erlbaum

7 Dec 7 Dec

8:15 a.m.

We tried this in an attempt to estimate 2010 fhwa adj urban boundary pop based on 2000 fhwa urban boundary and pl dataand we had great difficulty resolving slivers and the cartographic quality differences between the 2000 and 2010 geography files Nathan Erlbaum Associate Transportation Analyst Office of Policy, Planning & Performance New York State Department of Transportation 50 Wolf Road, 6th Floor Albany, New York 12232 (Tel) 518.457.2967 (Fax) 518.457.4944 (E-mail) nerlbaum(a)dot.state.ny.us (Web) www.nysdot.gov ________________________________________ From: ctpp-news-bounces(a)chrispy.net [ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher [edc(a)berwyned.com] Sent: Tuesday, December 06, 2011 7:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Steiss

8:39 a.m.

I'm working on a statewide travel demand model for North Carolina DOT and had to deal with this. The best method I could come up with is to use Census 2000 Tabulation Block to 2010 Census Tabulation Block relationship files. http://www.census.gov/geo/www/2010census/t00t10.html The files show you the relationship between 2000 and 2010 blocks (one-to-one, one-to-many, many-to-one, and many-to-many) but more importantly how much area of the 2000 block is in the 2010 block. So you can use this to redistribute your 2000 block data to 2010 geography using the percent area (or reverse the process if you want 2010 data in 2000 geography). Feel free to contact me directly if you are interested in learning more about this process. Todd steiss(a)pbworld.com 704-342-5411 -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher Sent: Tuesday, December 06, 2011 7:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news ______________________________________________________________________ NOTICE: This communication and any attachments ("this message") may contain confidential information for the sole use of the intended recipient(s). Any unauthorized use, disclosure, viewing, copying, alteration, dissemination or distribution of, or reliance on this message is strictly prohibited. If you have received this message in error, or you are not an authorized recipient, please notify the sender immediately by replying to this message, delete this message and all copies from your e-mail system and destroy any printed copies.

mkaminowitz＠baltometro.org

8:45 a.m.

Yeah, we are in the same boat. I have seen some interesting ways of getting around it but no perfect solution. Mara Kaminowitz GIS Analyst ......................................................................... Baltimore Metropolitan Council Offices at McHenry Row 1500 Whetstone Way Suite 300 Baltimore, MD 21230 410-732-0500 ext. 1030 mkaminowitz(a)baltometro.org www.baltometro.org Confidentiality Statement This message may contain legally privileged and confidential information that is intended only for the use of the recipient(s) named above. If you are not an intended recipient, taking any action based on the contents of this message is strictly prohibited. Please immediately notify the sender if you have received this message in error. -----Original Message----- From: Ed Christopher [mailto:edc(a)berwyned.com] Sent: Tuesday, December 06, 2011 7:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Uppalapati

9:19 a.m.

Hi, We faced similar situation in Southeast Michigan. In order to accurately depict change over time with geographic areas that also change over time, SEMCOG developed an equivalent "small area" geographic layer. Essentially, the new "blocks" in this geography would be a combination of blocks resulting in having same boundary in both Census 2000 and 2010. Using this new equivalent geography we are producing a series of change maps and analyses at the lowest geographic level possible. Sirisha Uppalapati Data Analysis Group SEMCOG, the Southeast Michigan Council of Governments www.semcog.org -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher Sent: Tuesday, December 06, 2011 7:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Graham

10:29 a.m.

New subject: [CTPP] Census Geography Question (Blocks)

We're most interested in TAZ zone-level, or place-level stats. (I can't imagine needing Block-level change statistics.) So, we recast all the year 2000 Block polygons as centroid points and use "spatial join" to attach a consistent-over-time TAZ code and place code (most recent jurisdictional boundaries). Then simply roll up Blocks into TAZ totals, place totals, etc. There are Blocks that straddle TAZ and place boundaries - just have to live with that. (I do repeat the step above 2 or 3 times as a quality control: I identify Block centroids using different centroid location options (thus moving the points around) and test to see whether that yields multiple membership in multiple TAZs or places. Then I go to aerial photography and manually recode TAZ and place membership based on "rooftops assessment": which side of the boundary line has the majority of structures, or else the majority of land acreage. This is an issue only in ½ % of Blocks.) Todd Graham | Principal Forecaster Metropolitan Council | 390 North Robert Street | Saint Paul, MN 55101 tel: 1+651-602-1322 | fax: 1+651-602-1674 | e: todd.graham(a)metc.state.mn.us<mailto:libby.starling(a)metc.state.mn.us> in: www.linkedin.com/in/toddgraham<http://www.linkedin.com/in/toddgraham> Visit www.metrocouncil.org/data for the latest in regional information. -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Uppalapati, Sirisha Sent: Wednesday, December 07, 2011 8:20 AM To: ctpp-news(a)chrispy.net Subject: RE: [CTPP] Census Geography Question Hi, We faced similar situation in Southeast Michigan. In order to accurately depict change over time with geographic areas that also change over time, SEMCOG developed an equivalent "small area" geographic layer. Essentially, the new "blocks" in this geography would be a combination of blocks resulting in having same boundary in both Census 2000 and 2010. Using this new equivalent geography we are producing a series of change maps and analyses at the lowest geographic level possible. Sirisha Uppalapati Data Analysis Group SEMCOG, the Southeast Michigan Council of Governments www.semcog.org -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher Sent: Tuesday, December 06, 2011 7:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Jonathan Lupton

10:08 a.m.

We have faced the same issue in the Little Rock area. Our GIS staff tells me that the 2010 blocks are more accurate; i.e. they match the actual geography more closely than the 2000 block geography did. Some of the change is that median strips are now shown, along with alleys in our downtown areas that were not in the 2000 block geography. There have also been some consolidations of areas that were previously 2-3 separate blocks. Direct comparison is problematic, but we have been able to mostly work around it so far. Jonathan Lupton AICP Research Planner Metroplan Little Rock AR -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher Sent: Tuesday, December 06, 2011 6:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Thera Black

2:05 p.m.

Ed, I checked in with our GIS folks about this. Here is Michael's response: There were significant changes in our blocks between 2000 and 2010, but I don't think census data was ever meant to be compared across decades on a block-by-block basis. Tracts are better for that. Census does publish Block Relationship Files (http://www.census.gov/geo/www/2010census/rel_blk.html) which could be useful, but these are not a one-to-one relationship. Hope this helps. Thera Thera Black Thurston Regional Planning Council 2424 Heritage Court SW, Ste A Olympia, WA 98502 360.956.7575 ext 2545 www.trpc.org -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Ed Christopher Sent: Tuesday, December 06, 2011 4:44 PM To: ctpp-news(a)chrispy.net Subject: [CTPP] Census Geography Question Today i got this question from an MPO friend of mine and was hoping others on the list could help me. Anyone experiencing similar issues. ------------- Ed We have experienced the frustration of block boundaries between the 2000 Census and the 2010 Census being dramatically different within our urbanized area. Our GIS experts have had a difficult time assembling and reconciling the differences in order for us to simply compare data on a block-by block basis. Do you know if this is unique to us or are we in the same boat as others? -- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C) _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news

Ed Christopher

5:38 p.m.

Actually it is perfectly acceptable to compare across decades at the block level because both data sets, after all, are censuses. A complete count of ALL the people not a sample. Unfortunately, with the geography issues being reported comparisons can get a little dicey. It's a real shame. I know for some block groups sometimes line up better but they too could have issues. Thanks to all who responded.

...

-- Ed Christopher FHWA Resource Center Planning Team 4749 Lincoln Mall Drive, Suite 600 Matteson, IL 60443 708-283-3534 (V) 708-574-8131 (C)

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Ed Christopher
Erlbaum
Graham
Jonathan Lupton
mkaminowitz＠baltometro.org
Steiss
Thera Black
Uppalapati