Principal Data
The choropleth map is colored according to values of the principal data. Once chosen from the data selection box, principal data are mapped and represented by the North slider, in color, as follows:
Cyan = small values of the principal data
Yellow = medium values of the principal data
Red = high values of the principal data
Black = A county with missing data or data that has been filtered out
Secondary Data
Secondary data are secondary map components that interact with the principal data. Once chosen from the data selection box, secondary data are represented in the East and/or South map titles (see also Map Features).
Conditioning the Principal Data
The South and East sliders enable you to subset the counties by using data ranges. When you activate the South or East slider and scroll or resize either, you filter that data according to percentiles. Only those counties with data values that fall within the percentiles (purple region of the slider) are shown on the map enabling you to condition the principal data on a subset of the secondary data to look for interaction. Initially the cyan color shows the lower 33% of counties in terms of county data values, the yellow shows the middle 34% and the red shows the top 33%. These groupings can be changed by moving or resizing the North slider, and the map is updated in real-time.
More about Sliders
Each Slider has four (4) percentile values above it and three (3) percentages below it. For the East slider, the percentiles are to the right of it and the percentages are to the left of it. Initially the percentiles are from left to right: The minimum county value (the 0th percentile), the 33rd percentile (the data value below which are 33% of counties), the 67th percentile (the data value below which are 67% of counties) and the maximum county value (the 100th percentile). For the East slider the percentages are from bottom to top.
If you wish to eliminate the effect of Secondary Data on the Principal Data, uncheck the East and/or South slider. Un-checking both sliders allows observation of only the Principal Data.
View Data Interactions
The North slider is used to define the percentile ranges for map coloring. Scroll or use the slider end-points to alter data ranges. The North slider end-points set the percentages of the distribution and the percentiles are calculated automatically. The extreme values of data can be shown by moving the lower end-point of the red band to the right, or by moving the upper end-point of the cyan band to the left. Note: The three color bands can be reduced to two, or one, by merging the slider end-points (see also Tutorial)
Using the Analyzer to Map Adhoc Data
Right click the map and select "Analyzer" from the popup menu. The Analyzer is used to create adhoc data by transforming data. Data variables associated with the South, East, and North slider are identified as X,Y, and Z, respectively. A transformation of the form f(x,y,z) is assigned to x, y, or z. The function f is formed using the operators +,-,*,/,^,(,).For example z = 100 * (z-x)/x assigns z as the percent change of z with respect to x. A dialog box will allow the transform to be input as well as an optional title. Click OK to run the transform and map the transformed data. The new map is displayed (see also Tutorial).
Using Dynamic Choropleth Maps