MOCO Map of the Week--Percent White by Census Tract 2010

Today's map looks at the distribution of the white population in Montgomery county.  People who identify as white comprise 59% of the population in Montgomery County.  The white share of MOCO's population is slightly higher than it is for the state of Maryland (58.2%), but substantially lower than it is for the country as a whole (72.4%). 

Two patterns stand out from this map.  First, the white population in Montgomery is clustered in three places--along DC's western border (and extending along the Potomac), in the county's most western tracts, and in the northern tip of the county.  Second, there are four tracts where the white population is greater than 90%, and all of them are located inside the beltway in Friendship Heights/Bethesda (see mini-map below). 

MOCO Map of the Week--Ethnic Clustering Part 2

Today's map is a slight variation on my last map, which showed the spatial distribution of the county's Black/African American population.  Today's map is a standard deviation map.  This means that each tract is categorized based on where the Black/African American share of the population fits in the wider distribution (i.e. within one standard deviation of the mean, within two standard deviations, etc.).


A bit on measurement:  In the tracts outlined in black the Black/African American share of the population that is greater than 2 standard deviations from the mean share.  The mean share of the Black/African American population is 16.62%.  The standard deviation is 13.58%.  Tracts outlined in black have a Black/African American share of the population that is greater than 43.78% (i.e. the mean + 2 standard deviations).  

So, what are the notable patterns here?  Unlike the earlier standard deviation maps I produced for the Asian and Hispanic populations (you can see them here), there are not multiple clusters.  Instead, all of the tracts with a statistically significant share of the Black/African American population are near one another and located on the eastern edge of the county.  In many ways the eastern orientation is not surprising given that Blacks/African Americans comprise a majority of the population in neighboring Prince George's County.  

MOCO Map of the Week--Percent Black/African American by Census Tract, 2010

Today's map looks at the distribution of Montgomery County's Black/African American population by census tract.

People who identify as Black or African American comprise 16.62% of MOCO's population.  Their share in MOCO is lower than it is for the state (29.4%), but higher than it is in the country as a whole (12.6%).

A few spatial patterns stand out on today's map.  First, the Black/African American population is spatially clustered in two places in the county--Gaithersburg/Montgomery Village and along the border with Prince George's County.  Second, the top 5 census tracts with the highest percentages of Black/African American residents are all located on the eastern edge of the county (either bordering the county, or bordering a census tract that does). Finally, the county's Black/African American population is largely concentrated outside the beltway, despite a significant cluster along the northeastern border of DC.

Next map will look at statistically significant clusters of the Black/African American population.  Stay tuned! 

Map notes:  The data for this map is from the 2010 census.  The census does not disaggregate between people who identify as African American and those who identify as Black (usually, though not always people from other countries with African heritage).  

Map of the Week Bonus Edition--Ethnic Clustering

This is for all you map lovers out there!

The last two maps I've made showed that the distribution of two minority populations--Asian and Hispanic--in Montgomery County.  Today, I thought I'd take a look at the degree to which these two minority groups are clustered in a statistically significant way.

Stay with me statistics phobes.  There are pretty maps involved!

One way to see evidence of clustering is to create a standard deviation map.  This means that each tract is categorized based on where the minority share of the population in that tract fits in the wider distribution (i.e. within one standard deviation of the mean, within two standard deviations, etc.).

Evidence of statistically significant clustering would be found in tracts where the Asian or Hispanic share of a tract's population is more than two standard deviations from the mean.  

For both groups--Asians and Hispanics--there a 12 tracts with significant spatial clustering.  On the maps below these tracts are shaded in dark blue and outlined in black (as opposed to gray).  For the Asian distribution this means tracts where Asians comprise 29.4% or more of the total population.  The comparable figure for the Hispanic population is 42% or more.

Although both groups have significant clustering, the clustering tends to happen on different sides of the county--north and west for Asians and south and east for Hispanics.

What to make of all this?  Montgomery county may be exceptionally diverse, but that diversity isn't evenly across space.


Map 1: Asian Share of the Population, Classified by Standard Deviation

Map 2: Hispanic Share of the Population

MOCO Map of the Week--Percent Hispanic or Latino by Census Tract 2010

This week's map shows the distribution of Hispanics in Montgomery County.  

The Hispanic share of the population in Montgomery County (17%) is slightly larger than it is for the US as a whole (16%).  By contrast it is double the share for Maryland as a whole (8%).       

In terms of the distribution of the Hispanic population, two patterns stand out on the map below.  First, Hispanics are clustered in a fairly narrow band running along a northwest-southeast axis.  The band doesn't follow one particular road, but it does run through three places in the county known for having large Hispanic populations--Gaithersburg, Wheaton, and north Takoma Park.  Second, most of the county's Hispanic population lives outside the Beltway (the black line at the bottom of the county).

MOCO Musings' next map will explore the degree of clustering for Hispanics.  Be on the lookout for a standard deviation map! (For map lovers a 'be still my beating heart' moment!)