Frequently Asked Questions (FAQ)

General Data Questions

What are aggregate data?
What is the source of IHGIS data?
For which countries does IHGIS have data?
Do I need special statistical software like SPSS, SAS, or Stata to use IHGIS data?

Data Access Questions

How do I obtain data?
How long does a data extract take?

Questions about Downloaded Data

Why do I receive so many data files in my downloaded zipped file?
What do the field names (e.g., AAA001, ABA005) in an IHGIS data file mean?
Something is wrong with the data I downloaded. What should I do?

GIS Questions

I don’t have Esri ArcGIS! Can I still map IHGIS data?
I downloaded some data tables and I want to map them. Where are the GIS files?
OK, I downloaded the data tables and the GIS files. Now how do I join them together?
What projected coordinate system are the GIS files in?

IHGIS Project Questions

Should I cite IHGIS in my paper? How?
What's next for IHGIS?
How do I get a job at IHGIS?
I have a suggestion for how you can improve your website! Do you want to hear it?


General Data Questions

What are aggregate data? Back to Top

Aggregate data summarize sets of individuals through counts, sums, means or other aggregate statistics. IHGIS specifically provides spatially aggregated census data: data summarizing individuals within particular areas, such as states or counties, where the "individuals" might be persons, housing units, farms, chickens, or any other features that were at some point counted in a census. No individual-level records, with or without personally identifiable information, are included anywhere in IHGIS.

What is the source of IHGIS data? Back to Top

Most IHGIS data were originally obtained from census results reports published on national statistical office websites. Most of these reports were published as PDF documents containing data tables as well as narrative text. In some cases, data were published as Excel files or other data formats. Links to the national statistical office home pages for the countries for which IHGIS has data are available on the Source Organizations page. Often, you will be able to find the original source documents on these sites, but there is no guarantee that they are still available.

The GIS boundary files draw on a variety of data sources. When possible, we obtain source shapefiles from the country's national statistical office or geographic agency. Most often, however, we identify boundary data in an international data source to use as a starting point. Common sources include GADM, the UN Second Administrative Level Boundaries (SALB) project, and the Food and Agriculture Organization's Global Administrative Unit Layers (GAUL). We then adjust the units in the geographic data as necessary to align with the units represented in the data tables. All shapefiles are aligned to the Large Scale International Boundaries (LSIB) dataset from the U.S.Department of State to ensure that the boundaries of neighboring countries will coincide.

For which countries does IHGIS have data? Back to Top
You can find a summary of the datasets available in IHGIS on the Dataset Descriptions page. We also have data for many more datasets at various stages in the processing pipeline. If you are looking for data from a particular country, send a note to ipums@umn.edu. We may have data that we could bump up in the queue.

Do I need special statistical software like SPSS, SAS, or Stata to use IHGIS data? Back to Top
Absolutely not! Any spreadsheet software like Microsoft Excel will work fine, and even that technically is not required. Statistical software may make it easier to analyze large amounts of data, but most IHGIS data tables are relatively small.

Data Access Questions

How do I obtain data? Back to Top
All IHGIS data are delivered through our data extraction system. Users select the data tables they would like, and the system creates a custom-made extract containing this information. Data are generated on our server, and the system sends out an email message to the user when the extract is completed. The user must download the extract and analyze it on their local machine. Users need to register for a free account before they can submit an extract request. Users do not, however, need to register or login prior to building an extract request. Detailed information on using the data extraction system is provided on the User Guide page.

How long does a data extract take? Back to Top
The time needed to complete an extract request depends on the size of the data extract requested and the load on our server. Most IHGIS extracts complete in under a minute. The system sends an email when the extract is completed, so there is no need to stay active on the IHGIS site while the extract is being prepared. You can also refresh your Extracts History page in your web browser any time after submitting a request to see if there's been a change in the extract status.

Questions about Downloaded Data

Why do I receive so many data files in my downloaded zipped file? Back to Top

A tabular data file is returned for each geographic level available for each data table requested. For example, if a country has nation, region, and district data for most tables, and you request three tables, you will receive nine data files.

Each data extract also includes four metadata files: a text file codebook and CSV files providing details about geographic levels, tables, and variables. See the "What's in an extract" section of the User Guide for details about the contents of these metadata files.

What do the field names (e.g., AAA001, ABA005) in an IHGIS data file mean? Back to Top
The key to these unique, IHGIS-created column names is found in the metadata files that were automatically included in your data extract. Look for the codebook.txt and datadict.csv files in the zipped file you downloaded, and they will shed some light on your data.

Something is wrong with the data I downloaded. What should I do? Back to Top
There are lots of reasons why something may seem wrong with your data. Sometimes errors are present in the published data. We generally do not attempt to correct errors in the published data, but we do try to document errors that we notice in the course of our processing. Of course, always feel free to contact IHGIS User Support at ipums@umn.edu with any questions you may have!

GIS Questions

I don’t have Esri ArcGIS! Can I still map IHGIS data? Back to Top
There are several options for those who do not have access to Esri ArcGIS. A number of open source GIS programs are available, including GRASS and QGIS. Another option for many students is a free student ArcGIS license, which can often be obtained through college GIS or Geography departments for class purposes, or by purchasing select books from the Esri Press. Student licenses vary in length, but are typically 6 or 12 months.

I downloaded some data tables and I want to map them. Where are the GIS files? Back to Top
GIS files are currently available on the Geography & GIS page. Separate shapefiles are provided for each geographic level available in each dataset. Download the one that matches the data table you wish to map. Additional information on using a GIS with IHGIS data can be found in the User Guide

OK, I downloaded the data tables and the GIS files. Now how do I join them together? Back to Top
IHGIS has made it as easy as possible to join data tables to their respective GIS files. In both files, you will find a field called GISJOIN that will serve as the join field. Additional information on using a GIS with IHGIS data can be found in the User Guide

What coordinate system are the GIS files in? Back to Top
IHGIS shapefiles are in the WGS 1984 geographic coordinate system.

IHGIS Project Questions

Should I cite IHGIS in my paper? How? Back to Top
Reports and publications using IHGIS data must cite IHGIS appropriately. See the Citation and Use page for IHGIS data use conditions and the current recommended citation.

What's next for IHGIS? Back to Top
We are continuing to refine and enhance our software and process additional data. Software enhancements behind the scenes will enable us to process table structures that don't quite fit our current models. You may also see additional features in the data access system. We have over 30,000 additional data tables from over 100 countries in the processing pipeline, and we plan to release new data several times a year. If you are looking for data from a particular country, send a note to iupms@umn.edu. We may have data that we could bump up in the queue.

How do I get a job working with IHGIS? Back to Top
We’re flattered you're interested in us! IHGIS is a part of the IPUMS Data Center, which is itself part of the Institute for Social Research and Data Innovation at the University of Minnesota, Twin Cities campus. Please visit the employment pages at IPUMS and at the U of M for up-to-date job postings for both students and professionals.

I have a suggestion for how you can improve your website! Do you want to hear it? Back to Top
Sure! We are always open to new suggestions. This does not mean we can always act on the suggestion, but many changes to IHGIS have come about through users’ suggestions. You may direct yours to ipums@umn.edu.

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