RESIDENT CENSUS
Describe the people at home.
ACS estimates describe the population living inside the selected block group: income, race, education, and unemployment.
VISITOR CENSUS / A GEODI LAB PROJECT
Every place.
Two populations.
A census tells us who lives here.
What about who comes here?
Meet the visitor census. A new lens on the social geography of cities, connecting neighborhoods through the people who move between them.
Explore the living city ↘
TWIN CITIES, MN–WI HOME → DESTINATION
Seven metropolitan areasBLOCK-GROUP RESOLUTIONJULY 2021 · RESEARCH DATAPublished in Scientific Data ↗
THE VISITOR CENSUS ATLAS
Seven metropolitan areas UNITED STATES
MAP CONTEXTLoading reference geography…
SEVEN STUDY METROS · JULY 2021
Loading research data…
SELECT A BLOCK GROUP TO EXPLORE
A CITY IN MOTIONMonthly profileExplore hourly patterns from July 19–25
ACROSS CITIES · FIGURE 4 REINTERPRETEDSame city.
Same city.
Different social geography.
Compare the distribution of block-group profiles across seven metros. Each curve represents places, not people. Switch attributes to see how the visitor lens changes the picture.
Hover over a curve to inspect both densities and their difference (or focus a plot and use arrow keys). Probability-density curves: area under each curve is approximately 1, not the number of block groups. Both axes are shared across all cities for each attribute. Markers show medians across available block groups. Resident and visitor tables may contain different numbers of records; this is a distribution comparison, not a matched-pair estimate. Percentages are shown in percent units.
From mobility records
to a visitor profile.
Traditional census data describe residential populations. The visitor census enriches the meaning of a place with the neighborhood characteristics of those who visit it.
TWO LENSES · ONE GEOGRAPHY
Who lives here? Who comes here?
Keep the block-group boundary fixed. Change whose characteristics describe the place. That is the distinction at the heart of the visitor census.
VISITOR CENSUS
Describe its visiting population.
Visitor counts connect this place to visitors’ home neighborhoods. Their census attributes are weighted by the detected visitors arriving here.
Same boundaries. Different social profiles.Visitor attributes are neighborhood-based estimates, not measured individual demographics. Diagrams are illustrative.
The calculation connects 2017–2021 ACS neighborhood estimates to inferred home–visit links from mobile positioning records. Each origin contributes in proportion to its detected visitors. Switch to an hour of day to see how the mix of origin neighborhoods changes.
Vj: visitor profile of destination block group j · Ai: census attribute of home block group i · nij: detected visitors from i to j · Oj: origins with a valid value for that attribute. A zero denominator yields a missing estimate.
What these data can—and cannot—tell us
Visitor profiles describe the census characteristics of visitors’ home neighborhoods. They are not directly observed individual incomes, races, education levels, or employment status. Income is a weighted average of origin block-group median household incomes, not a median of individual visitor incomes. Origins outside each study metro are excluded, and mobile-device sampling introduces coverage bias.
The map uses published July 2021 monthly visitor estimates. Hourly views and origin connections are derived from the released July 19–25 Home-Visit tables. Summing hourly counts produces visitor-hour observations, not unique people over the week. Curved connections link block-group representative points; they are not observed travel routes. Boundaries are simplified for display. Map context uses Census 2020 incorporated-place boundaries (places with at least 5,000 residents) and a bundled October 2026 TIGERweb water snapshot. These reference layers are generalized for orientation; they do not change the census values.
Resident table identifiers are checked before spatial matching. Missing values remain missing.
Dataset: Xiong, Zhu & Van Riper, Figshare (CC BY 4.0). The atlas reinterprets Figure 2’s geographic connections and Figure 4’s distribution comparisons. It does not reproduce Figure 2’s proprietary raw positioning-record or home-detection totals.
SCIENTIFIC DATA · 12, 1106 (2025)
A visitor-enriched census in the U.S. cities using large-scale mobile positioning data
Meicheng Xiong · Di Zhu · David Van Riper