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Thread: GIS help (population data)

  1. #1
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    GIS help (population data)

    Thought I'd ask here.

    We are looking for the number of KOREAN VOTING AGE population (so they
    have to be 18 and older, and US Citizen) in the Los Angeles County area.

    How can we go about this? The 2010 census data seem grouped (by ASIAN) and do not specify whether they are citizens.

    Any help would be greatly appreciated!

  2. #2
    Cyburbian WSU MUP Student's avatar
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    Quote Originally posted by yk2366 View post
    Thought I'd ask here.

    We are looking for the number of KOREAN VOTING AGE population (so they
    have to be 18 and older, and US Citizen) in the Los Angeles County area.

    How can we go about this? The 2010 census data seem grouped (by ASIAN) and do not specify whether they are citizens.

    Any help would be greatly appreciated!
    The Decennial Census no longer asks for detailed place of birth but the American Community Survey does. Unfortunately, I do not think that there is a table that breaks down place of birth by age or citizenship status. After a quick search, the closest information that I can come up with is that there are 150,902 Korean-born residents in LA County according to the 2009 American Community Survey. I know that information is quite incomplete compared to what you are looking for. You may want to check with the Homeland Security/INS or the local South Korean Consulate General's office to see if they have more detailed information (DHS/INS probably doesn't report much below the state level though).

    Here, when we get questions on topics that the federal government doesn't provide much detailed information about (i.e.immigrant or religious groups) we often check with large local non-profits or churches that are active in those communities and whom may have their own tracking mechanisms in place. Another resource might be one of the larger universities in the LA area like USC or UCLA who probably have some sort of academic research center on Asian-studies particular to the local area (I know here in the Detroit area, Wayne State has one for the Boricua population).

    If you don't mind paying for the data, private market research firms like Nielsen/Claritas may also have some information available. We've had to use them a few times for some data and the costs were significantly less expensive than what we were anticipating and they are very helpful walking you through what's available when you call.
    "Where free unions and collective bargaining are forbidden, freedom is lost." - 1980 Republican presidential candidate Ronald Reagan

  3. #3
    Cyburbian JimPlans's avatar
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    Census 2010 did ask about place of birth in Question 9 (the "race" question). The SF1 release has the count of Korean-born persons available in Tables PCT5 and PCT7 (using slightly different definitions). However, there is no age data available by country of birth (or "detailed race") in SF1. That will be released in SF2 starting in December.

    Data in SF2 will only be available for areas with at least 100 persons of that ethnicity, and will not be available below the Census Tract level. So, if an area has at least 100 persons of Korean descent, and is at least the size of a Census Tract, you will be able to pull a great deal of detailed data for that population group.

    http://2010.census.gov/news/pdf/data...10_census2.pdf

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    thank you so much.
    I decided to go with the 1-year 2009 ACS survey but it seems there is no COMBINATION of Koreans who are 18 year and over, and US Citizens. They only have separate numbers for them. Is the combination even possible in the near future? I contacted the agencies and they said you can get different variations but they are not sure when it's going to come out.

    Also, do we still have to convert the .txt files downloaded from American Factfinder, and convert it to .dbf file on Access to be readable by ArcGIS? That's what they recommend, but I currently don't have the Access software and was wondering if the technology improved where we can read it straight from ArcGis, or if there are other programs that can take place of Access. Thank you so much for your help! I really appreciate it.

  5. #5
    Cyburbian
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    Also, do we still have to convert the .txt files downloaded from American Factfinder, and convert it to .dbf file on Access to be readable by ArcGIS? That's what they recommend, but I currently don't have the Access software and was wondering if the technology improved where we can read it straight from ArcGis, or if there are other programs that can take place of Access.
    Do you have Excel? You could try to open the file there, save it as an Excel file (.xls), and then bring that directly into ArcMap (I didn't test this, but it should work). If you don't have Excel, I'm not sure what to suggest. Open Office?

    I've never tried opening the sort of file you're talking about in Arc; so, I'm not sure what would happen. I always assume I have to do some processing to make it ESRI friendly.

    Good Luck!

  6. #6
    Cyburbian WSU MUP Student's avatar
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    Quote Originally posted by JimPlans View post
    Census 2010 did ask about place of birth in Question 9 (the "race" question). The SF1 release has the count of Korean-born persons available in Tables PCT5 and PCT7 (using slightly different definitions). However, there is no age data available by country of birth (or "detailed race") in SF1. That will be released in SF2 starting in December.

    Data in SF2 will only be available for areas with at least 100 persons of that ethnicity, and will not be available below the Census Tract level. So, if an area has at least 100 persons of Korean descent, and is at least the size of a Census Tract, you will be able to pull a great deal of detailed data for that population group.
    The "race" question on the 2010 Census form is not the same as place of birth. Somebody filling out the 2010 Census might check the box for Korean if they were born here but both of their parents were born in Korea. Previously, the long form census questionnaire, which was discontinued after 2000, had question #12 which asked where the person was born and they would check the box for "United States" or the box for "Outside the United States" and then fill in the name of their birth country in the space below.

    The American Community Survey still asks where an individual was born just as the old long-form census did.

    Quote Originally posted by yk2366 View post
    Also, do we still have to convert the .txt files downloaded from American Factfinder, and convert it to .dbf file on Access to be readable by ArcGIS? That's what they recommend, but I currently don't have the Access software and was wondering if the technology improved where we can read it straight from ArcGis, or if there are other programs that can take place of Access. Thank you so much for your help! I really appreciate it.
    If you just need the data in order to join or relate it to an existing shapefile, I'd recommend saving it as an Excel file and then importing that directly into ArcGIS. This might be a new option though and I think if you are working with something older than ArcGIS 9.0 or 9.1 you will still need to save it as a .dbf file. The .xls option is much quicker but if you plan to keep this particular table of data and possibly link it to other tables or change the information saved in it and reuse it frequently, it will probably be more efficient in the long-run to run it through Access and save it as part of a geodatabase.
    "Where free unions and collective bargaining are forbidden, freedom is lost." - 1980 Republican presidential candidate Ronald Reagan

  7. #7
    Cyburbian JimPlans's avatar
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    First, the 2010 1-year ACS is in embargo status now, and will be released tomorrow (I believe). 2010 ACS data is benchmarked to the 2010 Census, so it should have better estimates on countries of origin. Remember that all previous ACS releases are benchmarked to Census 2000, so race and ethnicity estimates are benchmarked to that year. I expect to see some areas have significant changes in their estimates because of this.

    Also, remember that the Decennial Census doesn't ask about citizenship, but the ACS does. So, if citizenship status is important (not just voting age people), you'll need to use ACS data. If this is a redistricting-related question, however, citizenship doesn't matter, just age.

    The only way you'll get thsi answer out of ACS data is to use PUMS (microdata). IPUMS or DataFerret can help you create a query that pulls out only citizens who are of Korean descent and over 17. If you don't know how to use PUMS data, then take WSU MUP Student's advice above and contact an expert. The California State Data Center is a good place to start.

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    I'm confused on the ACS data that is coming out tomorrow. Can you clarify this?

    THis is what I got from the 1-yr ACS data. Here is the link. Would it be diff from this?

    http://factfinder.census.gov/servlet...mat=&-_lang=en

    Also, I realized even when i download the excel files, it just looks like a table chart. It does not look like an attribute table where I can join tract shapefile to. Do you know how i can convert American factfinder data to fit GIS? Is this what you mean by I need to use PUMS?

    I appreciate all your help.
    Last edited by yk2366; 20 Sep 2011 at 8:39 PM.

  9. #9
    Cyburbian JimPlans's avatar
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    Quote Originally posted by yk2366 View post
    I'm confused on the ACS data that is coming out tomorrow. Can you clarify this?
    First, I can clarify that tomorrow refers to today's tomorrow, not yesterday's tomorrow (which would be today).

    Quote Originally posted by yk2366 View post
    THis is what I got from the 1-yr ACS data. Here is the link. Would it be diff from this?

    http://factfinder.census.gov/servlet...mat=&-_lang=en
    It would be the same data, but for 2010. If you compare 2009 to 2010, you may see some seemingly significant changes (or you may not). Remember that these changes may not be truly significant, because (a) ACS 2009 is based on Census 2000 geography, and ACS 2010 is based on Census 2010 geography, so you may just be seeing the effect of a change in geography, and (b) ACS 2009 is benchmarked to population counts in Census 2000, so if population counts changed in an unanticipated manner between 2000 and 2010 there will be adjustments to ACS 2010 numbers to reflect this. In other words, be wary of reporting significant-looking changes in the data between 2009 and 2010, they may not be real.

    Quote Originally posted by yk2366 View post
    Also, I realized even when i download the excel files, it just looks like a table chart. It does not look like an attribute table where I can join tract shapefile to. Do you know how i can convert American factfinder data to fit GIS? Is this what you mean by I need to use PUMS?
    I recommed using PUMS because it allows you to create custom tables that show exactly the data you want to use. Unless you want to wait for SF2 data in December or later, the only way you are going to get a table that shows only U.S. cisizens of Korean descent who are 18 years of age or older is to make a custom table in PUMS from ACS 2009 data. This is complicated if you've never done it before, so you're probably better off asking an expert to help you. Note that, even though ACS 2010 data is being released tomorrow, ACS PUMS data will not be released for a few weeks.

    There are few (no?) methods for downloading data from American FactFinder that create a spreadsheet file that is ready for joining with ArcGIS data. You need to manually adjust the spreadsheet to be a flat file with geographic identifiers in the first column and variable names (rendered appropriately for ArcGIS) in the first row. It is up to you to ensure that the geographic identifiers are in the correct form (numeric vs string, same number of characters, etc.) to allow you to join the data with your ArcGIS layer.

    I have had better luck joining Excel files withArcGIS 10 than with previous versions.
    For ArcGIS 9.x and before, I have taken the time to convert the file to a DBF and set the data type in the ID column to match the ID column in the target shapefile. For ArcGIS 10, I've been able to join directly to the Excel file (once it is properly formatted).

    My rule for using GIS is that 90% of my time is spent formatting the data to analyze, and only 5% is spent on the actual analysis. The other 5% is spent cursing.

  10. #10
    Having spent far too much time importing census data into ESRI products, JimPlans description was excellent.

    My only suggestion is that cursing takes up about 10% of the time. But then maybe he is better at GIS than I am (or more polite).

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    I LOLed about the cursing part. It is definitely frustrating and I'm so glad I have this board to ask such questions.

    Thank you for clarifying. My organization actually got access to embargo so we had the updated 2010 1-yr estimates. But as you have stated, it seems just the updated version, not something that shows both combination.

    "Unless you want to wait for SF2 data in December or later, the only way you are going to get a table that shows only U.S. cisizens of Korean descent who are 18 years of age or older is to make a custom table in PUMS from ACS 2009 data."

    From what you've written above, does SF2 data include the combinations that I'm looking for? and even if I got help from someone who may know PUMS, how would I make a custom table from the 2010 1-yr estimtaes with the combination of factors when I just dont know the numbers combined?

    I spoke to the census help lady and she told me that there are no pick and choosing of variables. They just show it this way and there's nothing we can do to format it. but she seemed uncertain. is this true?

    Thank you so much. I am learning so much.

  12. #12
    Cyburbian JimPlans's avatar
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    Quote Originally posted by yk2366 View post
    From what you've written above, does SF2 data include the combinations that I'm looking for? and even if I got help from someone who may know PUMS, how would I make a custom table from the 2010 1-yr estimtaes with the combination of factors when I just dont know the numbers combined?

    I spoke to the census help lady and she told me that there are no pick and choosing of variables. They just show it this way and there's nothing we can do to format it. but she seemed uncertain. is this true?
    Not everyone is familiar with Public Use Microdata, so not everyone knows that you can actually pick and choose your variables, with restrictions. The biggest restriction is geography. PUMS data is only available for Public Use Microdata Areas (PUMAs). Each PUMA has to have at least 100,000 people in it. A map of PUMAs for California is here: PUMAs for California. If the PUMA geography works for your analysis, then you can create whatever table you want. Be warned that PUMS is a 1% sample of the population, so small sample sizes will have large margins of error (that you have to calculate yourself). PUMS data is difficult to use, so it's best to find someone who knows how to use it.

    Census 2010 SF2 data will not tell you about citizenship status (something I keep forgetting). Only ACS can tell you that. So if you wait for SF2 data, you will be able to see people who identify themselves as "Korean" in the race question, but this will not tell you if they are citizens (or even if they were born in the U.S.). They could have been born in Korea themselves, or their great-grandparents could have been and they are as American as apple pie. You will be able to get a detailed table that shows the age of everyone who identifies as Korean by Census tract (as long as each tract has at least 100 people in it who identify as Korean).

    Custom PUMS ACS data can show you who was born in Korea and became a naturalized citizen, whose parents were born there but they were born here, by age, sex, or whatever. Again, the fault is that, the more you slize-and-dice the data, the smaller the sample size will be, and the higher the margin of error. Did I mention that PUMS data is hard to use?

    Good luck.

    EDIT: Links to PUMS documentation and IPUMS:

    http://www.census.gov/acs/www/data_d...documentation/

    http://usa.ipums.org/usa/
    Last edited by JimPlans; 21 Sep 2011 at 6:54 PM. Reason: Add some links

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