Tag Archives: Population
On December 16, 1811 a violent earthquake shattered a winter night along the Mississippi River Valley in an area of present-day northeast Arkansas. While the region was sparsely settled at the time, the local European and Native American inhabitants were being introduced to what would only be the beginning of a nightmarish winter framed by the mid-December occurrence, followed by another main event in late January, and an even more fierce temblor in early February centered outside the village of New Madrid in the Bootheel of present-day Missouri. The community was effectively destroyed, while in St. Louis, over 150 miles upriver, houses were severely damaged with chimneys crashing down. All of the principal shocks were felt far to the east with amazing reports coming from cities as far away as Boston and Toronto. In between and into the spring, numerous aftershocks were triggered and felt. Together, these were the largest earthquakes to have occurred since European settlement east of the Rocky Mountains in the US and Canada.
I grew up near this region and have experienced first-hand what can happen in this seismically active area. A few years ago, I created a blog series and a map project using ArcGIS Explorer Desktop to examine some aspects of the region. My work then was triggered by a sizeable event in the spring of 2008 in southern Illinois. Today’s blog post draws a bit from that series but its main purpose is to highlight a new map I’ve been building using ArcGIS Explorer Online, a growing array of map services found in ArcGIS Online, and some CSV files I crafted and added to my map. Not surprising, the map is focused on the Bicentennial of the New Madrid Earthquakes.
Rather than describe the specifics of what the map contains, I have instead added that information as “metadata” and discussion at the map’s storage location in ArcGIS Online, as well as links to some USGS resources. Here’s a mini-URL that you can share, www.esriurl.com/NewMadrid. Once you are at the site, open the map in either the default option, Explorer Online, or the ArcGIS.com mapviewer. Also, rather than take you on a guided tour, here instead are a couple of screenshots of what you’ll discover.
Historical earthquakes and recent events
Historical earthquakes and nearby populated places
Please feel free to augment what I have done and save your own version of the map by logging in with your Esri Global Account, doing a “save as,” and share the new map. If you do craft your version, be sure to add your own description and other information for other users.
Also, remember the New Madrid Seismic Zone and similar zones in the Central US are active. Be sure to examine current population densities in these areas to begin to understand the human risk in a region not immediately recognized as a hazardous area.
Lastly, stay tuned for an Esri Map Story on this topic later this week.
- George Dailey, Co-Manager, Esri Education Program Manager
Remember field trips? Weren’t they eye-opening? Sadly, concerns over funding, “seat time,” and liability limit what many students get to do these days. But educators can still conduct virtual field trips, exposing elements in the neighborhood, which students can then explore later on their own. Even when “the real thing” is available, virtual field trips can provide important background and alternative perspectives.
Since it is hard to visit everything in all directions, one strategy for exploration is to do a transect — a swath thru the landscape — getting a representative feel for conditions. With ArcGIS Online, it’s easy to build a virtual transect, covering a distance of a reasonable walk, bicycle, or drive out away from the school. The various basemaps and numerous overlays provide a powerful look at the community. You can see an example by searching ArcGIS Online for “virtual transect” (or just click the image).
Open the presentation and walk thru the introductory concepts. The example displayed is for the school in the little town of Waterville in rural Washington. It will likely differ from where you live, highlighting a key feature of these virtual trips: the chance to compare widely disparate communities. Follow the guidance of the presentation and use the tools built into ArcGIS Explorer Online to make points, lines, and areas on the map. Generate the content, classify it, and symbolize it, then integrate the additional layers of data to understand how the local landscape differs from other noteworthy sites.
Virtual transects cannot completely substitute for actual experience in the real world, but they do offer a chance to analyze local patterns and compare the more familiar with the less so. Such analyses and comparisons are key for grasping why people see things as they do, and how “applied geographers” in a thousand careers build the holistic understanding vital for making good decisions.
- Charlie Fitzpatrick, Co-Manager, Esri Schools Program
In my last blog, I discussed a new lesson and data set, entitled “Population Drift: Mean Center Analysis 1790-2010” in the ArcLessons library, which uses spatial analysis, spatial statistics, and GIS to determine and analyze the population centers of the USA and individual states over space and time, from 1790 to 2010. One of the most fascinating parts of this lesson is examining the movement of state population centers.
This map shows the movement of mean center for each of the 48 states from 1900 to 2010, with the 1900 center shown as a blue square and the 2010 center shown as a red square. Nevada’s mean center of population moved the farthest, making a beeline north to south from the mining areas near Virginia City in 1900 toward fast-growing Las Vegas. Similarly, the influx of residents to southern California and the decline of mining tugged California’s mean center toward Los Angeles, though the San Francisco Bay cities kept the center from moving as much as in Nevada. Colorado’s mean center moved from the Rocky Mountains to the Great Plains, inexorably toward Denver. In Kansas, the center moved west until 1920 as the high western plains were settled, but then reversed as a result of high plains population loss beginning with the Dust Bowl and continuing to the present day. Why did Virginia’s center move north? Why did some state centers move very little? In which state is the population center the furthest from its geographic center?
How might you use this lesson and data set to teach about the many economic, political, demographic, and perceptual forces that pull on the population center of each state? Where will these centers move in the future? How might you use these same techniques to analyze how the population center of a metropolitan area or a county moved over time? How might you use GIS to determine where the mean center of ethnic groups in your community or people of specific age ranges are located? Why are these centers not necessarily in the same location as the mean center for the whole population?
- Joseph Kerski, Education Manager
Analyzing the Mean Center of Population for the USA and for Individual States, Updated for ArcGIS 10 and Census Year 2010
A new lesson, entitled “Population Drift: Mean Center Analysis 1790-2010” in the ArcLessons library
(http://edcommunity.esri.com/arclessons/lesson.cfm?id=568), invites students to use spatial analysis, spatial statistics, and GIS to determine and analyze the population centers of the USA and individual states over space and time, from 1790 to 2010. This lesson was recently updated to include 110 in-depth questions, a very rich set of data including the new 2010 county population figures, and to use the powerful spatial statistics tools in ArcGIS 10.
Objectives of this lesson are to 1) Understand the definition of and application of mean center and weighted mean center; 2) Understand the definition and use of a population weighted mean center in a GIS environment; 3) Learn how to calculate mean population centers for the USA and for individual states using GIS tools; 4) Understand the magnitude and direction of movement and key reasons why the US population center moved from 1790 to 2010; and 5) Analyze how and key reasons why population centers for individual states moved from 1900 to 2010. Skills include calculating mean centers, selecting and using spatial and attribute data, and symbolizing and querying maps. The investigation of population change and population centers naturally lends itself to discussions of job creation and loss, economic conditions, perceptions of place, the evolution of agribusiness and rural outmigration, urbanization, suburban sprawl, sunbelt migration, changes in the median age, changes from industry to services, international migration to the USA, and a whole host of other issues. Examining the population center for individual states allows students to consider how these issues operate on a state scale.
The Census Bureau recently published information on the location of the new 2010 USA center of population, as well as a series of interactive maps showing the 1790-2010 movement, on: http://2010.census.gov/2010census/data/center-of-population.php.
Linked to the page is a series of videos from Census Bureau Director Robert Groves who discusses the movement of the population center. These interactive maps and videos provide excellent supplementary materials to the ArcGIS-based lesson.
How might you use this lesson to teach about the many economic, political, demographic, and perceptual forces operating over the decades?
-Joseph Kerski, Education Manager
The folks at Nordpil.com have placed a layer package of the large urban areas of the world on ArcGIS Online. Not only is the data set comprehensive, containing urban areas with more than 750,000 people, but it also includes historical data back to 1950 with projections to 2050. The population data came from the UN Population Division’s World Urbanization Prospects’ 2007 Revision Population Database. This population data was matched to the ESRI Data & Maps 2008 cities dataset, and coordinates for matching cities were retrieved using Hawths’ Tools. Nordpil placed a Creative Commons license on the database, made it available for download in several formats, and created an animation, a KML, and a map. More information about the data is available on Nordpil’s web site.
This data set illustrates a topic that we on the ESRI education team have been excitedly writing about recently in this blog: ArcGIS Online. One of the best things about the layer packages on ArcGIS Online, including this one on world cities, is that they are wonderfully simple to start using. Simply clicking on the layer package on ArcGIS.com opens it in ArcMap.
Using attribute queries or through symbolizing the data, you can determine the spatial pattern of the fastest growing and the slowest growing cities, how growth rates of cities will impact specific countries’ infrastructure and economies, which cities will add the most people to the world’s population based on their growth rates, and much more. Using buffer and intersection tools, you can determine the percentage of cities that lie in and thus impact specific ecoregions, cities that are nearest certain types of hazards such as potential sea level rise or volcanoes, and dig even deeper by using spatial statistics. In the above example, I normalized the 1950 population with 2050 population. The dark blue cities are growing the fastest, while the red cities are growing the slowest. What patterns do you notice, and what implications does this have? These investigations can foster the most crucial questions of all: Why? And: So what? In other words, why does it matter?
I invite you to use this resource to teach and learn about the world’s urban areas.
-Joseph Kerski, ESRI Education Manager
A new lesson on the ArcLessons (http://edcommunity.esri.com/arclessons) library invites investigation into how and why state populations have changed from 1790 to the present. The 67 questions in the lesson include work with maps, graphs, and geodatabases in a GIS environment with a rich data set of cities, states, federal lands, highways, rivers, and other features for spatial and temporal analysis.
The two main focal points of the lesson are: (1) What is the spatial pattern of population totals and rates of change by state in the USA from 1790 to 2005? (2) What factors account for the variation in time and region? Learners begin the lesson by making thematic maps of age, ethnicity, and other variables to uncover key reasons for population change, examining not only the raw numbers, but also the rate of change. They create new variables, compare different classification methods, and experiment with different types of graphs. Learners also calculate the mean center of population and investigate the movement of this mean center over time. Why and how has the mean center moved, and where might it move in the future? What impact did the development of large cities have on state population growth and change? Metadata about the dozens of variables available for analysis is included in the lesson. The lesson provides step-by-step guidelines but leaves room for much further investigation.
Through these investigations, learners use GIS to reconstruct the settlement of the USA for the past 220 years. Learners perform tabular and spatial data query and analysis and dig deep into spatial analysis. Thus, the lesson is a mixture of GIS skills with solid content rooted in geography, history, and social studies, suitable for the secondary or undergraduate classroom.
We invite you to investigate this rich data set and uncover the “whys of where” in a historical and spatial context.
- Joseph Kerski, ESRI Education Manager
A new lesson and data set in the ArcLessons library (http://edcommunity.esri.com/arclessons/lesson.cfm?id=411) invites investigation of the 10 most populous cities in the world for the past 2000 years using GIS as the primary investigative tool. This lesson illustrates how easy it is to take an existing lesson (in this case, from the Our World books from ESRI Press (http://www.esri.com/ourworldgiseducation) and expand it to invite deeper investigation.
Students examine the pattern of the 10 most populous cities from the year 100 to the year 2005, noting the changes in spatial pattern and populations. Next, they predict the 10 most populous cities in 2050 based on the growth rates of countries around the world. They think critically about how population figures were derived in ancient times and today.
Next, students examine the geographic mean centers of the 10 most populous cities for each year. The center represents a pencil point that would balance the 10 most populous cities if the cities lay on a planar surface. The mean centers are weighted by population, so the larger cities pull at the mean center more than the smaller ones.
The mean weighted center for the 10 most populous cities has moved counterclockwise over the past 2000 years, starting in Iran and landing in Eritrea. Students describe and explain the direction and amount of movement of the mean center and predict where it will be by 2050.
Next, students examine the directional distribution for the top 10 cities for each of the years under study. This standard deviational ellipse measures whether a distribution of features exhibits a directional trend. The smaller the ellipse, the more clustered the top 10 cities are. If the spatial pattern of the features is concentrated in the center with fewer cities toward the edges, a one standard deviation ellipse covers 68% of the cities. The ellipse was smallest in 1900 as industrialization attracted migrants to the cities of London, Paris, and New York.