Tuesday, April 19, 2011

Concept Map

Concept Map- a diagram showing the relationships between words and ideas using boxes, arrows, and other figures. 



A concept map is used to see the structure of information, to organize and represent knowledge. They frequently use words and symbols to convey relationships in information. The map above is a concept map about concept mapping- it shows the purpose and structure of concept maps, as well as other information relevant to these maps. 

Bathymetric Map

Bathymetric Map- a map of the sea-bed surface showing depths below sea level. 



Bathymetric maps are similar to surface topography maps. This map shows the first realistic bathymetric map of any ocean basin, created between 1873 and 1875 in the Gulf of Mexico. 

Bilateral Graph

Bilateral Graph- a graph that shows the changes in two related variables. 



A bilateral graph is often used to show how the changes in one variable affect the changes in another. They can show both negative and positive changes. This bilateral graph shows the relationship between gas prices and consumer spending during 2007. Just after gas prices rose in May, spending went down, but spending rose as gas prices rose in November, presumably in anticipation of Christmas. 

Correlation Matrix

Correlation Matrix- a matrix or table showing the inter-correlations between all variables. 



A correlation matrix shows the similarities between all variables of a study. These matrices show the correlations between 20 climate models in four different areas. Each row and column of the matrix is a model, and the colors indicate how the models are similar or dissimilar to each other. 

Monday, April 18, 2011

Lorenz Curve

Lorenz Curve- a graph in which the cumulative percentage of a variable is plotted against the cumulative percentage of the corresponding population. The extent to which the curve falls below the equality line indicates the inequality of the distribution. 



A Lorenz curve indicates the inequality of a distribution. This graph shows the proportion of internet users to the total population. The straight diagonal line is the line of equality. The curves below it correspond to different years. As you can see, the proportion of internet users is becoming increasingly more equalized from 1997 to 2005. 

Parallel Coordinate Plot

Parallel Coordinate Plot- a graph that displays data in several dimensions. Each variable is graphed on a vertical axis and each data element is plotted as a connected set of points, one on each axis. 



This parallel coordinate plot shows grades received by the author at the University of Konstanz between 2001-2006. The first vertical line is the year variable, with each point being a separate year. The next vertical line is the grade variable, with points represented from 1 to 4. The last vertical line is the subject variable. 

Isopleth

Isopleth- a line on a map connecting points having an equal incidence of a specified meteorological figure. 



This map shows mean annual snowfall in North America. The isopleths connect points that receive equal mean snowfall. The numbers on the lines show what level of snowfall they represent, with snowfall measured in centimeters. 

Index Value Plot

Index Value Plot- a graph that shows the index value for each point, which is the ratio of the value to the total of all the values, instead of a concrete number. 



This index value plot shows the shift in ocean temperatures from 1900-2008. Orange values are above average temperatures, and blue values are lower than average temperatures. The article with this graph argues that changes in ocean temperatures are common and long-lasting, and that a rising ocean temperature is not necessarily related to intense climate change. 

Similarity Matrix

Similarity Matrix- a matrix of scores which represents the similarity between two data points. 



This is a similarity matrix for The Beatles' "Hey Jude". The deep blue parts represent repeating parts, and the lighter and more yellow parts represent dissimilar parts. The matrix is constructed by comparing the similarity of measures of music. 

Digital Line Graph

Digital Line Graph- a format used by the USGS to prepare a digital vector version of a topographic map. 



Digital line graphs can be downloaded for use from the USGS. They display the features from a topographic map in digital form. They are accompanied by a user guide, without which the features are hard to identify and access to their information is limited. This is a DLG of Beaufort, SC.

Star Plot

Star Plot- a method used to examine relative values for a single data point. 



A star plot has a sequence of spokes, with each spoke representing one variable. The data length of the spoke is proportionate to the magnitude of the variable. Star plots are often shown with multiple plots in one diagram, to compare observations. This diagram shows 16 star plots for different types of cars. The variables are: 1 price, 2 mileage (MPG), 3 1978 repair record (1= worst, 5= best), 4 1977 repair record (1= worst, 5= best), 5 headroom, 6 rear seat room, 7 trunk space, 8 weight, and 9 length.  

Isobar

Isobar- a line connecting points with the same atmospheric pressure at a given time or the same average over a given period. 



An isobar is another type of isoline. Isobars connect areas with equal pressure, and can help determine areas of high and low pressure. In the map above, the isobars indicate an area with rapidly changing pressure, which led to very high winds across the area. This map is from May 6, 1999, and the website it came from provides an analysis of why the high winds were created. 

DRG

DRG- digital raster graphic- a digital scan of a USGS topographic map. 



A digital raster graphic is a digital image of a scanned paper USGS topographic map. DRGs are used in GIS and mapping applications, and are useful as a backdrop for layering other digital data to check for accuracy. This map is a section of a DRG for Bushkill, PA. 

Weather Map

Weather Map- usually a satellite map with a variety of overlays on it. It will have isobars showing pressure, radar for showing precipitation or clouds, and colorful graphics to make the information easier to understand. 



Weather maps combine many different types of map into one finished product. This map has doppler radar, which shows the precipitation over different parts of the country. The key for intensity of precipitation is at the top. Isobars (the white lines) show areas of equal pressure, but don't really tell you how to read them. The graphic symbols for highs and lows show areas of pressure, and the blue line indicates a cold front. This map contains a lot of information but most of it probably doesn't make sense to the average viewer- only the precipitation is pretty intuitive.

Range Graded Proportional Circle Map

Range Graded Proportional Circle Map- a proportional circle map that uses a set number of circles to convey the magnitude of the data. Each circle corresponds to a geographically distinct area. 


A range graded proportional circle map uses only a set number of circles, while a continuously graded proportional circle map uses an unlimited number of circles to show the differences in data. In a range graded map, the numbers of data are rounded to make each area fit a set circle. This map shows the German population in the Chicago area, but the data is not conveyed as accurately as it would be with a continuously graded map. 

Continuously Graded Proportional Circle Map

Continuously Graded Proportional Circle Map- a map that uses proportional circles to indicate change in magnitude of a factor. The circles come in all sizes to reflect all possible magnitudes of data. 



This map shows the amount of voters by state and metropolitan area who voted for Obama or McCain in the 2008 election compared with those who voted for Bush or Kerry in the 2004 election. There are many different circle sizes- they are not limited to just four or five. The circle is proportionate to the number of voters. 

DOQQ

DOQQ- digital orthophoto quarter quad- an aerial photo that has been digitally corrected so that the scale is uniform and is has the same lack of distortion as a map.



The biggest difference between a DOQQ and a standard aerial image is that the distortion inherent in an aerial photo has been removed. A DOQQ starts with an aerial photo, which is then georectified to eliminate distortion caused by camera tilt and terrain relief. DOQQs can be used as the base for other maps, while aerial photos should not be used for base maps. 

LIDAR

LIDAR- light detection and ranging- a remote sensing technology that uses laser scanning to collect height or elevation data. 



This LIDAR image shows an area where a coastal landslide occurred. A LIDAR view was taken from each of the six numbered locations in the image, and then compiled to get the current image. The colored areas show where the landslide occurred, and the colors represent elevation. Blue is the highest and red is the lowest. 

Isoline Map

Isoline Map- a map containing lines that join points of equal value. 



An isoline map contains any type of isoline, which joins points of equal value. Types of isolines include isotachs, isopleths, and isohyets. This map contains isolines that join points of equal precipitation. All the points are mapped and then joined by the lines, and the area in between lines is shaded to show how much precipitation it received. 

Sunday, April 17, 2011

Choropleth Map

Choropleth Map- a map that uses predefined differences in shading or coloring within predefined areas to indicate the average values of a property or quantity within those areas. 




A choropleth map uses a color scheme to show differences in a variable that is being mapped. Most choropleth maps only display one variable at a time, and can be made on any scale- country, state, county, etc. This map shows the acres of hay harvested across the US, with the scale being by county. The darkest counties have the highest harvest, and the lightest counties have the lowest. 

Black and White Aerial Photo

Black and White Aerial Photo- a photo that is taken from a plane or satellite using black and white film. 



Aerial photos are used to study areas and make maps. Aerial photos are useful for studying an area over time, such as studying environmental or habitat changes. All aerial photos display some degree of distortion, though, specifically at the edges of the photo. To fix this, the photo must be adjusted for distortion before it can be used to make measurements. 

Infrared Aerial Photo

Infrared Aerial Photo- infrared photography shows the infrared part of the spectrum, which can not be seen by the naked eye. Infrared photos show objects based on how much infrared light they reflect back. 




Infrared photography is used to see things that are not visible in normal light. Normal objects react differently to infrared light than they do to in visible light- for example, foliage is reflected red, with the brighter red being the most healthy. Parking lots, pavement, and water reflect bluer, like the water around the community here. This picture is from Discovery Bay, part of the Delta National Park in California's Bay Area. 

Statistical Map

Statistical Map- a map that shows the spatial variability of a specific distribution or theme. Statistical maps contain a base map with some kind of reference information and the statistical data. 



This statistical map shows the unemployment rate in each state in March of 2009, with the lowest rates in green and the highest rates in orange. The key at the top shows the colors that correspond to the rates, as well as the national average to compare each state to. A statistical map is very similar to a thematic map in that it shows data for a subject or theme in a cartographic setting, as opposed to a reference map. 

Cartographic Animation

Cartographic Animation- a map that incorporates animation to show a change in some dimension, commonly a change over time. 



This map reflects trends in population from 1910-2000. Each point of light equals 10,000 people, and from the map it is easy to see how the major urban centers grew and when. Other maps that are in conjunction with this one show the black population as a percentage of the total population, and the differences between where blacks settled versus where the total population settled. Maps like this one make it easy to convey a lot of data in one map, instead of having to make ten separate maps and then read them in order. 

PLSS Map

PLSS Map- a map used by the Public Land Survey System to survey and identify land parcels. It is divided into townships and ranges. 




A PLSS map is used to identify land parcels throughout the US. The map is created using a principal meridian and a base line, along which townships and ranges are mapped. Each state has at least one base line and one principal meridian, although some have multiples, especially if they are far from a rectangular shape. The map above shows all the townships in Alabama, and the ones that are highlighted are the Franklin county townships. 

Thursday, April 14, 2011

Triangular Plot

Triangular Plot- a two-dimensional map in which three variables are mapped. The ratios of the three variables are plotted as positions within an equilateral triangle. 




A triangular plot can depict interactions with variables in different positions or how the different variables relate to each other. In the above diagram, the variables are the fields listed along the outside of the triangle and the data points are the specific sciences listed within the triangle. Chemistry is very much a disciplinary science and an earth system science, but not at all a decision making field. Politics is very much a decision making field, but not at all a disciplinary science or an earth system science. Engineering is squarely in the middle of the disciplinary sciences, earth system sciences, intergration, interpretation, and decision making. 

Isotach

Isotach- a contour line that joins points of equal or constant wind speed. 




Isotachs are another kind of isoline. Isotachs can be mapped in the upper or lower atmosphere. They can be used to analyze wind flow and can be important in weather predictions. This map also includes wind barbs to show the direction that the winds are flowing in. 

Hypsometric Map

Hypsometric Map- a map that uses a systematic application of colors to represent relief. 



On a hypsometric map each color represents an amount of elevation above or below a baseline. Some hypsometric maps include the contour lines of elevation, while others omit them. Some maps, like the one above, use shading so that there is not a distinct break between each color and the elevation is conveyed in a more fluid manner. Generally, green represents the lowest elevation, then up to yellow and tan and brown, with white at the top. This map shows a hypsometric color scheme for an area of Washington state. 

Thematic Map

Thematic Map- any type of map or chart that is designed to show a spatial pattern of a theme or a series of attributes. A thematic map can show any kind of statistical information, as opposed to a topographic map. 



"Thematic Map" is a very broad category, which can include many more specific types of maps. They can have qualitative or quantitative data, display large or small areas, and show any number of topics or themes. The main qualifier of a thematic map is that it displays statistical data of some description, rather than physical features of a landscape. This map shows population change in the provinces of Canada between 1996 -2001. The amount of change is conveyed both with the color of the province and the height from the baseline of the map. 

Digital Elevation Model (DEM)

Digital Elevation Model- a digital model of elevation or altitude that can be represented by regularly or irregularly spaced point height values. 




A digital elevation model represents ground surface or topography. It is computer-created from data that are plotted on a map and then filled in to create a 3-dimensional map. Digital elevation models can be tilted and rotated to make each feature more accessible and to aid viewing of the overall area. This map is a digital elevation model of a part of Lesotho, in southern Africa. Red is the highest elevation and dark blue is the lowest. 

Stem and Leaf Plot

Stem and Leaf Plot- a graph used to organize and display data so that frequency can be compared. 



A stem and leaf plot organizes data with the largest place value in the "stem" position and the smaller place values in the "leaf" position. It is useful for comparing a set of data to see frequencies and outliers. This graph shows the heights of 218 volcanoes, with the unit being 100 feet. The majority of the volcanoes mapped are between 2,000 and 8,000 feet high, and the fewest mapped are around 14,000 feet and 18,000 feet high. 

Isohyet

Isohyet- a line on a map connecting points with the same amount of rainfall in the same period. 




This map shows the rainfall in the Sabah forest, a forest reserve in Malaysia. The darkest areas have the highest rainfall, and the lightest areas have the lowest. The boundaries of each color are formed by isohyets, a type of isoline. 

Doppler Radar

Doppler Radar- a radar tracking system that uses the Doppler effect to determine the location and velocity of a storm, clouds, precipitation, etc.



Doppler radar uses the apparent shift in the frequency of radio waves to perceive air motion. It can sense precipitation, clouds, and other movements of the air. Doppler radar is most commonly used to track precipitation in weather forecasts, and to predict the movements of precipitation in the air. This map shows the Doppler radar of hurricane Charley as it made landfall on Florida. The key at the top of the map shows the intensity of the precipitation, in this case rain, with red being the highest (in this map) and green being the lowest. This map is only showing precipitation, not clouds. 

Climograph

Climograph- a graphical representation of the average monthly precipitation and temperature at a given location. 




A climograph is an easy way to get a feel for the weather in a location. It does not show specifics, but rather monthly temperatures and precipitation. The precipitation is graphed with bars, and the temperature is represented with a line graph. Reading one y-axis gives the amount of precipitation, and reading the other gives the temperature. This graph is for Honolulu, Hawaii, and shows the coordinate location, elevation, and total annual precipitation and average annual temperature at the bottom. 

Dot Distribution Map

Dot Distribution Map- represent density using dots- each dot on the map represents a given object(s). 



A dot distribution map represents density and location of a phenomenon. This map shows coral reefs- each dot is the location of a reef. From this map it is easy to see that all coral reefs occur within the tropic zones. On other maps, each dot could represent a household, 100 people, or a specific kind of business- there are endless options that could be mapped. They are useful to show density and the exact location of the phenomenon, which might be more generalized in a choropleth map. 

Propaganda Map

Propaganda Map- a map that shows biased or misleading information as a means of promoting or publicizing a particular political cause or point of view.



A propaganda map is used, like any other type of propaganda, to sway public opinion with misleading, biased, or falsifies information. Propaganda maps seem to be especially popular during wartime periods as a means of inspiring patriotism, anger, and fear. This map is a Japanese map from the Russo-Japanese War of 1904-1905. The Japanese are shown as anguished victims, and Russia is shown as an octopus reaching its tentacles across all of Europe and Asia. The aim of this map would have been to remind the Japanese of their positions as victims and encourage them to fight back. 

Cartogram

Cartogram- a type of thematic map in which the areas of spatial features are distorted in proportion to the value of an attribute. 




Cartograms show land area in proportion to the attribute being mapped, so they are distorted to make a point. This is a cartogram of projected internet use by 2015, with each country represented by its flag. Each country is still in its relative location to the countries around it, but the size has been changed to reflect the relative number of internet users, not just the population. For example, Canada has a large land area, but on this map it is a small piece just perched on top of the US, because the amount of internet users in Canada is much smaller than the amount in the US. Cartograms can cause confusion, though- for example there are not fewer internet users in Canada because it is less developed than the US but because it has a smaller total population. 

Proportional Circle Map

Proportional Circle Map- displays data in relation to the size of circles on the map. Usually used to convey numerical data. 




A proportional circle map uses circles of proportional sizes to convey information about data shown in the map. The circles represent numerical values, such as population, occurrence of lightning strikes, or amount of people using alternative transportation. A formula will be used to determine the size of each circle based on the numerical value. Generally bigger circles = a higher number. Here the circles show the Hispanic population of each state, not as a percentage of overall population but as a finite number. In my opinion this map could have been made more informative and readable by making the starting circle size bigger, so that more of a difference could be seen more easily. 

Isopach

Isopach- a line on a map connecting points of equal thickness in a stratigraphic layer. Used to indicate rock thickness. 




Isopach maps are used in stratigraphy, sedimentology, structural geology, petroleum geology, and volcanology. Connected lines indicate points of equal thickness, similar to isobars or isotachs. This map shows Michigan in a stage of rock development. The thickest rocks occur at the bay where the 4000 is located, and the thinnest rocks occur at the southernmost edge of the state. This map is from the Silurian period of sedimentary rock development. 

Scatterplot

Scatterplot- a relational chart that displays the X,Y coordinates on a grid. The correlation of the point helps to determine a trend in the data. 



Here hours of study and test scores are plotted on a graph, with each point representing one person or test. Each point is charted independently on the graph, from which a conclusion can be drawn. Because the point show a positive relationship between more hours of study and higher test scores, it can be assumed that studying more will positively affect the test score. If the points were more randomly distributed, it would be harder to come to a conclusion, or the conclusion might be that more hours of study does not affect the test score. 

Wednesday, April 13, 2011

Histogram

Histogram- a bar chart representing a frequency distribution. A histogram is different from a bar graph because in a histogram the bars must all touch each other so that the measured data measurements on the x-axis are continuous. 




This is a (made up) histogram of the salaries of employees of a big-box chain. The chart starts at the lowest salaries and moves in even increments of $10,000 up to $200,000, above which everything is grouped together. It shows that the largest group of employees is getting paid the lowest salary, the managers (presumably of individual stores within the chain) are getting paid an average salary and there are far less of them than of the lowest employees, and the top executives, who are the smallest group, are getting paid the most. It is a histogram because the frequencies are represented with bars and the x-axis variable moves evenly upwards. Even though this chart is made up, in my opinion it is a fairly accurate representation of the compensation methods of a company like this. 

Cadastral Map

Cadastral Map- a map depicting land parcel boundaries. 




This is a map of the District of Columbia from 1917 showing government buildings, all other buildings in the mall area, and public lands. From the map it is easy to tell how the early center of Washington D.C. was divided into a grid system, and then parceled out into smaller pieces. This map does not include all of the information that might be found on a cadastral map, though, such as portion and plan numbers and parish and county names and boundaries. 

Population Profile

Population Profile- a chart showing the number of people as a function of their ages- also called a population pyramid. 




A population profile shows the number of people in each age group within a country. Here, the profile shows each age group as a percentage of the total population, instead of as a calculated number. They are always divided into male and female populations. From a population profile, it is possible to discern events that have affected the population of the country. This is a profile of Finland, with two different years shown. A label points to the Great Famine, showing how the population from that time is significantly smaller. Other labels show the Baby Boom generation as a rise in the total number of people and the subsequent decline in birth rates as a smaller percentage of the population. 

Windrose

Windrose- a diagram indicating compass directions on terms of eight principal winds. 



Windrose is the original name of the compass rose, which is used to indicate direction on maps. This windrose shows the directions of the eight major winds- Tramontana, Gregale, Levanter, Sirocco, Ostro, Libeccio, Poniente, and Mistral. Winds were used to determine crop-growing seasons and for navigation of trade ships around the Mediterranean.