John Dougherty

Geog 370 Sec 006

2/22/2010

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44/50

Part I.

  1. Print screen of map from extra challenge on p. 469.

  1. What is the dimensionality of each of the data layers?

Landmarks are polygons

Shorelines are lines

Waterbodies are polygons

The population data are points

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Explanation: For both the dot density and chloropleth maps, the geographic data is defined in terms of bounded areas (polygons). The attribute table makes this clear because it has a data row (an entry) for each area/polygon on the map. Data is calculated in terms of these areas and visualized as dots or colors as per that area/polygon. Dots are randomly placed within the polygon and therefore are not point data.

  1. Print screen of resulting bx_demog layer resulting at end of task 4, p. 480.

Justifythe number of classes that you use and the breaks in the data.

The data layer defaulted to use 5 classes. While 5 may have been sufficient I though 6 layers would more effective show minor variations without overtaking the map with classifications. The changed the breaks to an equal interval distribution to ensure that each classification contained an equal percentage of the data.

While this is easy to understand the classes, it is not a particularly good way to represent the geography of this particular dataset

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4. What measurement levels of data are mapped?Ordinal data

Nominal- minority race/ethnicity is a subjective category with without quantitative degrees of difference and to which the concept of “zero” is meaningless.

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5. What are the two types of thematic maps covered in these exercises? What

questions are they best to describe?

Dot density and choropleth maps. Dot density is best for showing the absolute frequency of the presence of a feature. The dot distribution represents the actual frequency of a feature within a unit of analysis. The choropleth map also represents numeric data, but is not used to counts. It represents variation in the relative frequency of a feature by classifying the data into classes and then shading each class on the map.

Part II.

1. Create informative layout of the data that you have worked with over the past 2

weeks. Include legends, titles, north arrow, scale, text, and bar chart. Text should

describe 1) name, section, and date , 2) data sources, and 3) describe the maps that

are displayed. Include dot density and chorpleth maps. Bar chart should be

properly labeled with title, legend, and use one option from your choices. The

final layout will be judged according to visual structure of the layout as described

in lab.

Sources?

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