Tuesday, June 24, 2008


Here is an isopach map displaying the ash fall from the Cerro Negro Volcano in Nicaragua. Isopach maps are frequently used to assist geologists. They map the areal extent and thickness variation of a stratigraphic unit.


Sunday, June 22, 2008

Remote Sensing

Image URL- http://www.dcs.gla.ac.uk/~hall/personal/files/Glasgow-Satellite.jpg
This image is of Glasgow, Scotland. It is the largest city in Scotland and the third most populated in the United Kingdom. This image depicts many different features of Glasgow, one in particular being the University of Glasgow. This University is well known for contributing to the Scottish Enlightenment. Many other features can be seen such as the River Kelvin.

Univariate Choropleth Map

A univariate choropleth map displays a single data set. Here only one set of data is displayed regarding poverty in the United States. http://www.cdc.gov/pcd/issues/2007/oct/images/07_0091_02.gif

Unstandardized Choropleth maps

Unstandardized choropleth maps utilize raw numbers when displayed. In the map displayed the data displayed is not averaged.

Standardized choropleth maps

Data in choropleth maps are standardized to allow comparison of distribution among different areas. Here is a map of Canada displaying the different area's population of people age 14 and under.

Nominal area choropleth map

Nominal area choropleth map is a choropleth map that is used to dispaly nominal data. Here is a map with nominal data showing which state's minority group has highest percentage of state population.

Bilateral Graph

A bilateral graph depicts increases on one side of a zero line and a decreases on the other side. Bilateral graphs are used to display data when there is both positive and negative values. Here you can see increases and decreases in humanitarian services in various countries.

Accumulative line graph or Lorenz curve

The lorenze curve graphically represents the cumulative distribution function of a probability distribution. It is frequently used to display income distribution. It was developed by Max Lorenze in 1905.

Index Value Plot

This index value plot helps display current streamflow with historical streamflow for the United States. The index value plot will help show discrepencies between data information.

Tuesday, June 17, 2008

Bivariate Choropleth map

Bivariate choropleth maps display two different variables displayed on one map by including two different sets of graphic symbols or colors. Here is a map depicting olympic athletes. You can see how this type of map can solve spatial problems. http://www.directionsmag.com/images/articles/sportsillustrated/Olympic_Athletes.jpg

Unclassed Choropleth Maps

This technique assigns shadings proportional to the data values so that these choropleth maps do not have to classify the data. This method of mapping has not been generally accepted because many cartographers claim that they lose the ability to direct the message of communication. http://www.agocg.ac.uk/reports/visual/casestud/dykes/figure9.gif

Classed Choropleth maps

A classed choropleth map the main objective is to determine height and shading or color intensity of the bar for each map classed. This would involve creating a classed frequency legend including a frequency histogram, a frequency curve, and shading.

Range Graded Proportional Circle Map

A range graded proportional circle map is a proportional circle map that depicts the circles in relation to ranges of data. The information is classified as equal quantiles, breaks, natural breaks, and minimum variance.

Continuously variable proportional circle map

A continuously variable proportional circle map is a proportional circle map which utilizes circles to create point data. This relates the scales to the specific data. The circles are in proportion to the variable being measured.

Correlation Matrix

A correlation matrix lists the variable names down the first column and across the first row. The diagonal of a correlation matrix always consists of ones. In every correlation matrix there are two triangles that are the values below and to the left of the diagonal and above and to the right of the diagonal. A correlation matrix is always a symmetric matrix.



A scatterplot uses Cartesian coordinates to display values for two variables froma given set of data. The data is then displayed as a collection of points which each having the value of a variable dermining the position on the horizontal axis and the other variable determining the position on the vertical axis.

Population Profile

Population profile maps present a graphic overview of several demographic statistics collected certain data. They can depict a wide range of variables through different methods.


A climograph is a graphical representation of the monthly precipitation and temperature conditions for a specific region. Precipitation is shown by the bar graph and a line graph depicts temperature.



A wind rose is a graphical tool utilized by meteorologists to depict how wind speed and direction are distributed at a specific location. It will show the frequency of winds blowing from certain directions. Each concentric circle stands for a different frequency which starts at zero in the center and increases in frequency in the outer circles.

Similarity Matrix

A similarity matrix is a matrix of scores which show the similarities between two data points. They are genearlly used in sequence alignment. The higher the score the more similar charachters it receives.

Stem and Leaf Plot

Stem and leaf plot is a way to show quantitative data in a graphical format to help visualize the distribution among categories. It came about from teh work of Arther Bowley in the early 1900's.

Box Plot

Box plots are very useful to graph groups of numberical data through their five number summaries. It was invented in 1977 by John Tukey who was an American. They are also used to depict differences in populations without making assumptions on statistical distribution.


histogram is a graphical display of tabulated frequencies. It shows what proportion of cases fall into each of several categories. There is a difference between a histogram and a bar chart in the sense that it is the area of the bar that dictates the value, not the height, which is a very important difference particularly when the variables are not all the same width.

Parallel Coordinate Graph

Multivariate relations are obtained through the use of these graphs. Specific properties of the relationship correspond to the geometrical properties of the graph.

Triangular Plot

A triangular plot displays information in a shape of a triangle. For example here is a triangular plot of election votes. http://ex-parrot.com/~chris/images/20050407/triangle.png

Star Plot

A star plot is a graphical data analysis method used for examining the relative behavior of all variables in a multivariate data set. Here is a star plot of crime rates in the United States.


An isopleth map generalizes and simplifies data with a continuous distribution. It shows the data as a third dimension on a map. They are mostly used for mapping surface elevations, amounts of precipitation, atmospheric pressure, and other measurements that can be viewed statistically as a third dimension.



An isohyet is a line joining points of equal precipitation on a map. A map with isohyets is called an isohyetal map. http://www.forest.sabah.gov.my/caims/Climatic%20information/Stations/Maps/Isohyet/isohyet.gif


Isotachs are lines on a given surface connecting points with equal wind speeds. The are seen sometimes in conjunction with isobars.


On a weather map an isobar is a line drawn on a map connecting points of equal barometric pressure. You will see them utilized with weather maps.


LIDAR (Light Detection and Ranging) is an optical remote sensing technologay that measures different properties of dispersed light to find range or other information of a distant target. The difference between lidar and radar is that lidar uses shorter wavelenths of the electromagnetic spectrum, generally close to infrared.
Here is a LIDAR image of lower manhattan.


Wednesday, June 4, 2008

Cartographic Animations

Cartographic animation has become a useful technique for representing geographical area's because of its capablilites to show relations between geospatial data's components, location, attribute, and time. They are typically used to display geospacial information. The goal of cartographic animation is to be able to visualize somethign that would not be seen if the maps were looked at individually.

Statistical Map

Statistical maps are used to display the distribution of a certain variable over a geographic area. In these maps each unit is represented by a shading technique or color that represents a value. The statistics shown on the map are expressed as rates, ratios, percentages, or other statistical measures.


A cartogram is a map where area is not presevered. Many times they are used to represent the size of populations relative to the area in which they inhabit. There are two main types of cartograms: area and distance cartograms.


Flow Map

Cartographers use flow maps to show the movement of objects from one location to another. They are easier to read many times because of the merge edges. They are used frequently when depicting migrations.

Isoline Maps

Isoline maps are a two dimensional representation of a three dimensional model. An isoline map give you a picture of the concentration of people.

Proportional Circle Map

Proportional circle maps display data in relation to the size of the circles. In this map data is displayed of internet users in Europe.

Tuesday, June 3, 2008

Dot Distribution Map

Dot Distribution Maps are useful to help show populations. Here shows the population of military families and where they live in relation to the state. You can see that military families live in every county in the state. http://operationmilitarykids.ohio4h.org/resources/images/dotMap.gif

Propaganda Map

Propaganda Maps are used to persuade people to think one way or another. They are well known for their use in WWII and WWI.

Hypsometric map

Hypsometric maps are used by cartographers to display elevation. They can utilize many different ways to depict this elevation. In this picture you can see color is used to display different elevation levels.


PLSS (Public Land Survey System) maps are used to divide up public lands which are owned by the Federal Government. These are created to help the citizens of the United States. Since these surveys were completed many changes have occured in regards to public lands being now privately owned and vice versa.

Mental Map


Mental maps refer to a person's point of view. They can be used to show a person's views regarding the size of their country in comparison with another country. These maps are subject to the opinions of the cartographer that is constructing the graph.

Infrared aerial photo

Infrared film is sensitive to a certain spectrum of light. It can be used to document changes in the environment and track various applications.

Choropleth Map

Choropleth Maps thematic map with areas shaded in reference to the statisitc that is being measured. Here is a map of Florida with areas shaded in regards to percentage of Hispanic population by percentage. As you can see, South Florida has a larger proportion of Hispanics compared to the rest of the state.