Comparing Metropolitan Areas In ArcGIS Online
A metropolitan area is a major city together with its suburbs and nearby cities, towns, and environs over which the major city exercises a commanding economic and social influence. Literally construed, metropolis from the Greek means "mother city," and by implication there are progeny or dependents scattered about the core area.
This tutorial covers how metropolitan areas in the USA can be mapped and compared in ArcGIS Online.
Metropolitan Statistical Areas
The US Census Bureau has a wide variety of different types of statistical areas that are used to aggregate data on communities for presentation and analysis.
Two of the Census Bureau area types commonly used with metropolitan areas are metropolitan statistical areas (MSA) and micropolitan statistical areas. These are called core based statistical areas because they each represent a core area containing a substantial population nucleus, together with adjacent communities having a high degree of economic and social integration with that core..
As the names imply, metropolitan statistical areas are larger with at least one urbanized area of 50,000 or more inhabitants, while micropolitan statistical areas must have at least one urban cluster of at least 10,000 but less than 50,000 population.
The USA Core Based Statistical Areas Living Atlas layer collects a wide variety of attributes for MSAs.
The filter can be used to limit viewing to just the metropolitan areas rather than both metropolitan and micropolitan areas.
A bubble map of total population shows a handful of large US cities surrounded by smaller metropolitan areas.
Spatial density is the amount of something that is contained within each unit of area. Population density is the spatial density of people living in an area, often expressed as the average number of people per square mile.
The average population density in the US is around 93 residents per square mile which can be found by dividing the total US population (around 327 million as of this writing) by the total US land area (3.5 million square miles). However, that is an average. There are many urban areas with much higher density than the average, such as the high-rise Co-op City in the Bronx with a density of around 33,000 residents per square mile. And there are areas of the US where humans do not live, yielding a population density of zero residents per square mile.
However, average population density is useful for comparing the level of urbanization of MSAs. MSAs with higher population density are more urbanized (more tall buildings, less open space) than MSAs with lower population density (more single-family homes on large lots).
High population density is associated with walkable communities that promote healthy lifestyles and require less energy per capita. However, places with high population density also often have a much higher cost cost of living and high levels of traffic congestion.
The CBSA Living Atlas layer contains a population density field that can be used to map population density. Although the same large metro areas stand out on this map as on the population density map, adjusting the color ramp shows that there are only a handful of very dense urban areas in the USA, which, not coincidentally, also happen to be both very popular and very expensive to live in.
Gross domestic product (GDP) is the monetary value of all the finished goods and services produced within an area during a specific time period. GDP is associated with material well-being and subsequently correlates with positive lifestyle aspects like health and nutrition, as well as more-problematic issues like energy use and environmental degradation.
The ESRI Living Atlas includes a Gross Domestic Product (GDP) by Metro Area layer that can be used to map absolute GDP by MSA. Again, we see a visual pattern almost the same as population, showing the correlation between population and economic output.
The political divisions within metropolitan areas are almost always the result of decades of political battles. As cities grew in the 20th century, outlying communities often resisted annexation to avoid additional taxation or loss of control over their own affairs. The result in many metropolitan areas has been municipal fragmentation, leaving a metropolitan area with a large number of competing cities that often find it difficult to address common problems. For example, depending on how you count, the Denver metropolitan area is comprised of around 50 separate incorporated cities.
You can visualize municipal fragmentation by including the USA Census Populated Places Living Atlas layer over the top of an MSA layer styled as an outline only:
ESRI's Tapestry is a data set that classifies US residential neighborhoods into 67 unique segments based on demographic and socioeconomic characteristics. The Tapestry data set is useful to businesses for targeting advertising and retail location choices.
The Tapestry data set is available as a Living Atlas layer with multiple levels of generalization from state down to census block, along with descriptive pop-ups that give Tapestry information about those areas.
The Tapestry segments are formed from 14 life mode groups, that are further divided into six urbanization groups, yielding a total of 67 Tapestry segments.