Tuesday, April 3, 2012

DEM

    
     A Digital Elevation Model (DEM) is a data set containing elevation values either in raster data form or in a Triangular Irregular Network (TIN).  These data sets are commonly created through remote sensing techniques but can also be made through land surveying.  This data is also regularly used in a GIS and is the basis for relief maps. The example shown above is the DEM of the contiguous United States. With this DEM, we are able to observe the commonly known mountain ranges of the U.S. (the Rocky Mountains in the west and the Appalachain Mountains along the east coast).

Black and White Aerial Photos

    


     Black and white aerial photography is data gathered in the visible spectrum rather than in the infrared.  In this part of the electromagnetic spectrum, black and white color values are exactly what we see in the visible spectrum. This aerial imagery allows us to analyze large areas of either developed or undeveloped land in a variety of different spatial resolutions. This black and white aerial example shows the reconstruction of Johnstown, PA in 1891; two years after it was flooded.

Infrared Aerial Photo


Infrared aerial photos are very useful to reflect the health of vegetation and also bodies of water. It can track temperature to monitor dangerous conditions in areas such as chemical plants and coal mines. Anything that gives off a heat signature can be shown on these amazing images. This image shows field-unit geometries in front of the background of color-infrared aerial photographics.

Cartographic Animations


     Cartographic animations are an important way of displaying results and falls with geovisualization.  Having a time series of information can inform the viewer of things that aren't necessarily apparent when looking from image to image without the assistance of an animation. Trends become distinct as we see images before and after a single frame. This can even allow us to make predictions and forecasts based off of previous behavior. This animation is of Hurricane Andrew that struck in 1992. The animation shows the progression of the hurricane as it traveled across the state of Florida.

Dot Distribution Maps



     These types of maps are an easy way to depict density of whatever variable is being plotted. The visual clustering of dots shows a high density of the variable occurring while large spacing inbetween the dots shows low density values. This example shows earthquake locations for events between 1965 and 1995. The red dots are shallow earthquakes, the green are intermediate depth, and the blue and purple are deep.

Digital Raster Graphic (DRG)




     A DRG is a digital image resulting from scanning a paper USGS topographic map so that it could be used on a computer. The raster image usually includes the original border information (also known as the map collar). The map file is then UTM projected and georeferenced to the surface of the earth. These are commonly used in GIS applications, also. This particular example is a DRG of an area in West Virginia.

Public Land Survey System (PLSS)


     A PLSS is a reference scheme for recording property ownership by section, township, range, and aliquot parts in the United States. It is surveying method used historically over the largest fraction of the United States to survey and spatially identify land parcels before designation of eventual ownership, particularly for rural, wild or undeveloped land. The system divides up the land into relatively equal partition which is easier to manage. It also helped  to facilitate the urbanization of areas by using a square block system for the road design. the example shown is a portion of the Minnesota's statewide PLSS base map; this view is a small part of the 1:100,00 scale Worthington quadrangle. This example makes it very clear to see the different numbered sections showing which land parts belong to which section.

DOQQ

    
     A Digital Orthophoto Quarter-Quadrangle (DOQQ) is an image that has been geometrically corrected so that the distance between two point is the true distance. They are recognized as one of several critical geo-spatial data sets needed to effectively manage and use geographic information systems in statewide, regional and local databases and spatial applications. This example shown about is part of the Farmville NE DOQQ. Maps of this type are often put into a GIS and are used to make vector data files.






DLG


      A digital line graph (DLG) is a cartographic map feature represented in digital vector form that is distributed by the U.S. Geological survey (USGS). DLGs are collected from USGS maps and are then distributed in various scales, and can have up to nine different categories of features depending on the chosen scale. This DLG example shows a section of Ottawa, Canada transformed into a digital vector form. This type of graph can be put into a GIS and used to maintain databases of relevant information.

Doppler Radar


     Doppler radar is a tool that makes use of the doppler effect to track objects at a distance. This type of technology is most commonly used in meteorology; more specifically used in tracking storms. Doppler radar allows us to pick up a storms size and speed; it can give us this information even days before it hits and area. The doppler radar shown above shows the size and speed of Hurricane Ivan before it hit the Gulf coast. The colors represent the intensity of the storm with red being the strongest.

Univariate Maps


     A univariate choropleth map is a type of thematic map in which the non-location data is all of the same kind; they only display a single variable. Population density, annual rainfall, and birth rates are all examples of univariate data. This map example shown represents the percentage of Americans living in poverty in different rural countries within the United States in 2008; people in the south seem to have higher poverty rates than those living in the north.

Unstandardized Choropleth Maps


     Unstandardized choropleth maps are thematic maps which contain data that has not been areally-averaged, though it still allows comparison between variables. This example shows the predictions of the 2008 Presidential Election. It displays the number of electoral votes of each state and is colored (red for republicans, blue for democrats) to indicate which candidate those electoral votes are predicted to go to.

Bivariate Choropleth Map


     A bivariate choropleth map is a thematic map that displays two variables or statistics by using two different sets of symbols or colors in order to illustrate a relationship between the two variables. This example shows the population density and percentage change in that population over a period of time in Russia. This is is considered a bivariate choropleth map because it is displaying the relationship between two variables, population density and percentage population change, and a different color scheme is being used for each variable.

Unclassed Choropleth Map

    

    

     Unclassed choropleth maps are similar to classed choropleth maps; however, unclassed choropleth maps do not have an averaged statistic towards each particular color. If you wish to create a map that maintains the data relation, unclassified data theoretically does a better job than classified data because unclassified data allows us to maintain the numerical relations between data. This means that the color shades on an unclassified map are directly proportional to the values of each enumeration unit; there are many shades of each color to show the diversity of the statistics. This unclassified map contrasts the democrats (blue) from the republicans (red). Most states are not completely republican or democratic so there are many shades of the combined blue and red which make a purple hue.


 

Classed Choropleth Maps



     This type of map allows a variable within different areas to be mapped; this helps with understanding the spatial distribution of this variable over larger distances. The variables that can be measured with this method are limitless. This classed choropleth map was created to show the population of Hispanic people per square kilometer in each state.

Standardized Choropleth Maps

 

     Standardized choropleth maps normalize data according to a certain area. They analyze data in the form of a percent so that areas of varying size can be compared to one another. In the choropleth map catagory, the standardized map is a better mapping technique for analyzing data because of the modifiable areal unit problem (MAUP). This example shows the population per square kilometer that is represented for an area divided into multiple areas. This map is standardized because it shows areas of different (population) sizes and depicts them by color so that they can be compared to one another. The darkest areas indicate locations with a higher population.






Saturday, March 31, 2012

Nominal Area Choropleth Maps

 
  Nominal area choropleth maps depict nominal area which is quantitative and random. The different colors on these types of choropleth maps depict variations in data. This particular nominal area choropleth map is broken into two divisions: the political party selections per state based upon the poor voters only. The blue colored states represent the democratic party and the red colored states represent the republican party.

Climograph


     A climograph shows how precipitation and temperature correspond during different times of the year. The precipitation is given in bar graph format and the temperature is plotted like a line graph. Together, these two characteristics create the climograph. This example shows the correspondence of precipitation and temperature for Rwanda from January to December with the rainfall measured in inches. With this type of graph, we can easily see that there is a greater amount of precipitation when there are lower temperatures in Rwanda.

Parallel Coordinate Maps


    These types of maps are used to show high-dimensional geometry and to analyze data that is multivariate. The above shows the parallel coordinate map of nine selected genes for all cells within the body.

Friday, March 30, 2012

Isohyets


Isohyets are line that connect areas of equal rainfall amounts. These values can change over different seasons and also over longer periods. This example shows the isohyets in Southwestern Australia. With isohyets, it is easy to observe how rainfall amounts increase as we move toward the coast.

Isotachs


     Isotachs are lines on a map that show areas of constant wind speed. Wind can also be used to track storm systems. Winds speeds at high spatial resolution through ground station is difficult and expensive, so wind speeds can now be detected through remote sensing satellites; these satellites give us a higher spatial resolution yet they do not always calculate accurate wind speeds. In this example, we can see how the winds from Hurricane Ike are depicted though using this remotely sensed data. Hurricanes create large pressure gradients in concentric circles from the eye; the isotachs are shown in the concentric circles and they show greater wind speed closer to the eye.

Isopachs


     This map contains isopachs, which are lines connecting points beneath which a particular stratum or group of strata has the same thickness. This example shows the isopach of flood deposits along the Brazos River in Texas. It shows the thickness of sediment deposits from flood and uses colors to distinguish more easily between the different levels. The thickness of the deposits is measured in centimeters.

Pictograph


     This is a pictograph: a map that conveys its meaning through its pictorial resemblance to a physical object. This example combines some of the features of a planimetric map in the way that it can show boundaries yet it also depicts what is in those bounded areas with more images. These images usually convey certain characteristics that are well known for an area. This pictograph of example of New York uses images of well known buildings.

Isotherms


     This map shows isotherms which are lines of constant temperature. This example shows how there are pockets of warmer areas across the nation (where the lines are further apart) and there several dips in temperature like in the Rocky Mountain region (where the area between the lines is narrow).

Windrose

 
     Windrose maps represent the direction in vector form of the wind at certain speeds. The frequency of the winds at that speed and direction can be determined based on the length of the vector. This example shows the data collected in Seattle, Washington where the most common wind direction appears to be almost due south. The colors in the vector indicate wind speeds in knots, and the legend is also shown to depict the colors.

Statistical Maps


     Statistical maps analyze many different atmospheric parameters and can also run into multiple problems in trying to calculate and display the data. This is where a Modifiable Areal Unity Problem (MAUP) comes into play; it is a potential source of error that can affect spatial studies which utilize aggregate data sources. Geographical data is often aggregated in order to present the results of a study in a more useful context, and spatial objects are the aggregating zones used to show results of some spatial phenomena. These zones are often arbitrary in nature and different areal units can be just as meaningful in displaying the same base level data. In this example, the prevalence in HIV AIDs in adults was calculated for every country in the world. This amount was also normalized to the total population within that country and the resulting values were placed along a color scale ranging from green to red (low to high). One can easily see with this type of map that the countries in Southern Africa have a high rate of HIV among its adults, and the same is with Africa.

Cartograms


     A cartogram is a map on which statistical information is shown in diagrammatic form. It uses some thematic variable which is substituted for land area or distance. The geometry of space of the map is distorted in order to convey the information of this alternate variable. This cartogram example show the HIV AIDs statistics; it bases the depicted area of the countries on how large their percentages are in relation to each other. The countries with the largest percentage of HIV among its people have the largest area and the countries with the smallest percentage are shown as smaller.

Similarity Matrix


     A similarity matrix shows how similar two variables are. It is a matrix of scores which express the similarity between the two variables. This particular example compares two photo indexes. The level of similarity is indicated by the colored boxes. Each color represents a level of similarity; the dark red being the most similar and the blue being the the least similar.

Wednesday, March 28, 2012

Lorenz Curve


     This is a Lorenz curve: a graph on which the cumulative percentage of some variable is plotted against the cumulative percentage of the corresponding population and is ranked in increasing size of share. The extent to which the curve sags below the straight diagonal line indicates the degree of inequality of distribution. This Lorenz curve shows the relationship between the percentage of households verses the percentage of income. The green line indicates perfect equality, the red line represents the Lorenz curve, and the blue line shows perfect inequality. One can see that 60% of income is concentrated in 80% of households; this means the income is not distributed equally.







Correlation Matrix



     A correlation matrix compares two things and the relationship between them. They can compare how well two things correlate by computing the correlation coefficients of the columns of a matrix. This particular correlation matrix is a calculated protein correlation matrix for phage T7. Correlated behavior ranges from high (red) to low (blue), and the triangular block of red reflects proteins involved in the phage assembly, a highly coordinated process.



Population Profile


A population profile displays age and sex population data for specific regions and can be presented in the form of a pyramid. This population profile example shows the percent of the population of males and females in each age division for the population growth of Mobile County. The light blue bars indicate the percent that is female, and the dark blue indicates the percent that is male. With a population profile, one can easily point out the highest and lowest percentages by looking at the lengths of the bars.

Bilateral Graphs


     These types of graphs compare two related variables that overlap one another. This particular bilateral graph shows data from the United States trade deficit in goods and services with the world. The red line indicates the values for the United States trade deficit in goods and services in 2010, and the blue line indicates the values for 2009. Bilateral graphs like this can easily present the change in values from month to month.

Index Value Plot


     An index value plot is a type of visualization map in which an index value, instead of and absolute value, is plotted on a line graph. This type of plot gives a comparison, or normal, in order to base the values off of. This particular example show the average streamflow index in North Carolina and ranged from mid February to the each of March. The average stream flow index is plotted based upon particular days of the week and the number value of comparison is 4.

Stem and Leaf Plots


     A stem and leaf plot is a plot that shows the shape of a distribution with each value separated into a base number, plotted in the stem, and the remaining portion, plotted in the leaf. The data found on the left hand side of the solid line is considered the stem and the numbers on the right are the leaves. This stem and leaf plot example shows the infant mortality rates in Western Africa. The rates range from 51 to 151.

Scatterplot


     A scatterplot is a type of plot that shows the relationship or trend between two types of data. The values are depicted by dots; after all values are plotted, a trend line is added in order to determine if there is a relationship between the two types of data. This scatter plot example shows the trend in a husband's age to a wife's age. The trend on this scatterplot shows that an increase in a husband's age will also cause an increase in a wife's age. Outliers are also present in scatter plots; they are the data points on the plot that are very much bigger or smaller than the majority of data points which are within the range of the trend line. In this example, you can clearly see the outliers which are further away from the other data points.

Histograms


     A diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval is a histogram. The rectangles are typically different colors to indicate the different categories, but can also just be labeled. This example of a histogram shows the final exam scores of a certain population of students. The number of students is depicted on the Y axis of the diagram and the possible final exam scores are depicted on the X axis. As you can see, most students scored in the 60-80 range.

Star Plots


     A star plot, also known as a radar chart, is a graphical method of displaying multivariate data in the form of a two-dimensional chart of three of more quantitive variables represented on axes starting from the same point. The relative position and angle of the axes is typically uninformative. This example of a star plot is a plot of MER IDD and other various designs. The different designs are compared in different categories, such as mass, time, trajectory completion, collision, accuracy, link deflection, and actuator saturation. The various colors are used to represent the various designs.

Triangular Plot


     A triangular plot is a graph which displays three types of data. Because there are three variables being observed, the different data is presented in a triangle in order to compare them. This triangle plot presents data from the UK from 2005 which depicts the percentage of liberal democrat, labour, and conservative votes. The white dot in the middle reprints the percentage of votes expected based upon polls.

Box Plot

   
     Box plots, also known as box or whisker diagrams, are useful in comparing multiple sets of data because they display the median, average, and level of dispersion. This particular box plot shows the data from five experiments along with the true value; these experiments tested the speed of light. The dark black line inside the boxes shows the median value of all the data combined from that particular experimental run and the true value of the speed of light is indicated by the red line.

Proportional Circle Maps


   These types of maps are similar to dot distribution/dot density maps because they use shapes to depict numerical values on the maps; however, the size of the circle on a proportional circle map is directly related to the data it presents, but not necessarily the area that it is covering. This particular map shows zinc deposits found in a small portion of Canada. The larger dots present a greater amount of zinc found in the soil. A distance scale is shown on the map so that the map reader can determine how much area the map covers and what the actual distance is from circle to circle.

Isopleths

   
     This particular map is an isopleth map; an isopleth is a line drawn on a map through all points of equal value of some measurable quantity. They generalize and simplify data with a continuous distribution. This isopleth map shows the hydrogen ion concentration made at field laboratories. As you can see, the ph is a lot higher on the western part of the US and extremely low in the north eastern part.

Thematic Maps


     This is a type of map especially designed to show a particular theme connected with a specific geographic area. They can portray physical, social, political, cultural, economic, sociological, agricultural, or any other aspects of a city, state, region, etc. They are not just for showing natural features; instead, these items are simply used as reference points to enhance one's understanding of the map's theme and purpose. This is a thematic map which because it shows the population percent change from 1990-2000 in the United States. As you can see, most of the western part of the United States has changed drastically along with Florida and Georgia and there has only been a little change in the northern eastern part of the United States. 

Isoline Maps


     These types of maps are a two diminutional representation of a three-dimensional model. It contains continuous lines joining the points of the same value. Examples would be equal altitude, temperature, barometric pressure, wind speed, wind direction, and wind shear. These examples more specifically use contour lines, isotherms, isobars, isotachs, isogons, and isoshears, respectively.  They are used to interpret the information on some thematic maps. This map has isolines (more specifically isobars) indicating changes in the pressure. It shows low pressure in the Middle of the states, and higher pressure on both the east and west.

Propaganda Maps


     False maps created with the goal of achieving a result similar to traditional propaganda are propaganda maps. This propaganda map was Nazi-generated and depicts the threat posed by the rest of the world to the German nation. The German propaganda machine evoked the Big Lie in this depiction of Czechoslovakia's aerial threat to the Nazi state. The Big Lie made Jews into persecutors and the German people into victims, even though this was the exact opposite of reality.

Hypsometric Maps


     Hypsometric maps represent the elevation of the terrain with colors. The area in-between two neighboring contour lines receives on specific tint. This particular hypsometric map gives the impression of the topography in Africa. There is a chart displaying what elevation each color depicts. The red indicates the highest elevations, the mountainous areas in central and south Africa. The green depicts the lower-lying areas like the vast flat desert of the Sahara.

Monday, March 26, 2012

Flow Maps


     Flow maps show the movement of objects from one location to another. They can be used to show the movement of almost anything: migration of people, imports and exports, and weather. These maps indicate what it is that moves, the direction the flow is moving, and where its destination is. They also can provide information about how much is being flowed or transported. Lines or arrows can be used to denote all of this information. This flow map represents the total combined truck flows from Texas through the rest of North America in 1998. The red lines are used to signify the movement of trucks departing from all areas of Texas.

Cadastral Maps


     This type of map provides detailed information about real property within a specific area. A cadastral map, also known as a cadaster or cadastre, can show the boundaries and ownership of land parcels. They can also include information about tax rates or which kinds of structures are present. These types of maps carry detailed information about location and show more than just the boundaries of lot lines; they provide measurements on each lot, and can also use GPS locations, so that people can understand where everything on the map is in the real world. Specific landmarks such as natural features and buildings are highlighted on the maps in order for people to orient themselves within the map. This particular cadaster was designed to provide more security to owners and potential buyers of property in Costa Rica by identifying property boundaries.

Wednesday, January 18, 2012

Topographic Map

      This is a topographic map; it is a large-scale map showing relief and man-made features of a portion of a land surface distinguished by portrayal of position, relation, size, shape, and elevation of the features. Unlike a planimetric map, it indicates both horizontal and vertical positions. Contour lines and shading are used in this example to represent the elevation of the land surface. At first glance, one can easily determine the shape of the land.

Mental map



                             http://www.fedstats.gov/kids/mapstats/concepts_mentalmaps.html
      Here, we have an example of a mental map. This type of map represents the perceptions and knowledge a person has of an area. Information used for daily tasks (buildings, streets, paths) is what creates a mental map. No mental map is alike because each one shows what a person knows about the location and uniqueness of their environment. This particular example is a mental map that someone made of their neighborhood. It may not be an accurate map, but it is their own expression of what they know about the neighborhood and how they percieve it.

Planimetric Map

                                        http://www.loc.gov/rr/geogmap/guide/gmillgen.html

      Here is an example of a planimetric map. It only indicates the horizontal positions of features, without regard to elevation. It is also know as a line map. This particular map shows buildings and the irrigation system in Shanghai. It is impossible to determine the elevation of anything because each feature is drawn with horizontal lines.