Fixed entitites, Can only take a specific value (Ex. number of students in a class, anything that is counted and not measured)
can assume all values between any two specific values. They are obtained by measuring.
Most popular form of USGS Map
map in which some thematic mapping variable is substituted for area (like a graph in a map)
explanatory list of symbols on a map
symbol on a map used to show direction
Parts of Map
title, legend or key, grid system, distance scale, direction and compass rose
The Land Ordinance
townships were six miles square, and were subdivided into 36 sections, each section consisting of one square mile. One section of each township was set aside to support public education, and the remaining sections were to be sold at public auctions.
To avoid corrupt data!
A map containing information on only one topic or theme.
maps that show the absolute location of places and geographic features determined by a frame of reference, typically latitude and longitude
sailors and pilots use these maps to navigate
a tabular file containing rows and columns; descriptive attributes about some object such as a geographic feature are contained in each row
classes based on natural groupings through examination of histogram (good: minimizes differences bad: data range uneven)
Are points taken at regular intervals from the cumulative distribution function (CDF) of a random variable.
A data classification method that divides a set of attribute values into groups that contain an equal range of values