GIS Fundamentals #2
9.9 - List and describe three different classification methods.
A binary classification is perhaps the simplest form of classification. A binary classification places objects into two classes: 0 and 1, true and false, A and B, or some other two-level classification. This equal-interval classification simply subtracts the lowest value of the classification variable from the highest value, and defines equal-width boundaries to fit the desired number of classes into the range. Equal-area classification. Class boundaries are defined to place an equal proportion of the study area into each of a specified number of classes. This usually leads to a visually balanced map because all classes have approximately equal extents.
9.11 - What is a dissolve operation? What are they typically used for?
A dissolve operation is often used in spatial analysis. Dissolves are routinely applied after a classification, as they remove redundant boundaries that may slow processing.
8.4 What is a one-to-one relationship between tables? A many-to-one relationship?
A one-to-one relationship among table means that for every row in one table that in some way is matched to a row in another table, there is only one row in the second table that matches. A many-to-one relationship means that one row in a table may match many rows in a second table. Note that by match, we do not mean completely match. Usually we are using a column in each table to match the tables; the rows are considered to match when the match column has the same value in both tables.
8.11 Does an AND condition result in more, fewer, or the same number of records as the component parts? For example, is the set from: condition A AND condition B the same, bigger, or smaller than the set from condition A alone, or condition B alone?
AND combinations typically reduce the size of the selected set when compared to the individual component criteria. They provide a more strenuous set of conditions that must be met for selection.
8.2 What are the primary functions of a database management system?
Database management systems are computer software tools that aid in the entry, organization, analysis, distribution, and presentation of data.
9.8 Reclassify the following polygons, according to the column Area, into small (<18,000), medium (18,000 to 45,000), and large (> 45,000)
Large are white, medium light gray, small darker grey
9.1 - Define and give examples of local, neighborhood, and global spatial operations.
Local operations use only the data at one input location to determine the value at that same output location (Figure 9-2, top). Attributes or values at adjacent locations are not used in the operation. Neighborhood operations use data from both an input location plus nearby locations to determine the output value (Figure 9-2, center). The extent and relative importance of values in the nearby region may vary, but the value at an output location is influenced by more than just the value of data found at the corresponding input location. Global operations use data values from the entire input layer to determine each output value. The value at each location depends in part on the values at all input locations
9.16 Select the most appropriate characteristics for the buffer below. Is it simple, multi-distance, or variable distance? Does it retain or dissolve intersections? Is it interior or exterior?
Multi-distance, retain, exterior.
8.6 Which single columns in the following table may serve as keys?
Osel, NumT
8.5 Which single columns in the following table may serve as keys?
Osel, NumT, Clr. Use the Common Fields to link the Tables. DO NOT Use FID, OID, or ObjectID
8.16 - Sketch an outer join for the table shown in the previous problem.
Outer join is to the right in the photo.
9.2 - Describe selection operations.
Selection operations apply criteria to features, and identify features that meet those criteria. The criteria may apply to spatial characteristics, for example, the size, shape, or location of a polygon; they may apply to non-spatial attributes of the features, for example the value or condition of an attribute.
9.3 - Describe set and Boolean algebra.
Set algebra uses the operations less than (<), greater than (>), equal to (=), and not equal to (< >). These selection conditions may be applied either alone or in combination to select features from a set. Boolean algebra uses the conditions OR, AND, and NOT to select features. Boolean expressions are most often used to combine set algebra conditions and create compound selections. The Boolean expression consists of a set of Boolean operators, variables, and perhaps constants or scalar values.
8.10 Does an OR condition result in more, fewer, or the same number of records than the component parts? For example, is the set from: condition A OR condition B the same, bigger, or smaller than the set from condition A alone, or condition B alone?
Sets from OR conditions will have the same number or more members than the component conditions.
8.1 What are the main components of a database management system?
The basic components of a traditional database are data items or attributes, the indivisible named units of data (Figure 8-3). These items can be identifiers, sizes, areas, coordinates, colors, or any other suitable characteristic used to describe things.
9.5 - Write the simplest Boolean expressions that result in the grey area selection:
a) A and B and C b) A and B c) C D) not { A and B and C }
8.13 - Identify the countries from the following table that meet the following criteria. a) Per capita energy use > 4,000 and population < 20,000,000 b) Infant mortality < 7 and life expectancy > 79.0 c) Per capita energy use < 4,000 or ((population > 40 million) and (car theft < 1)) d) [Per capita energy use < 4,000 or (population > 40 million)] and (car theft < 1) e) not (population > 40,000,000) f) Population < 20,000,000 and not (car theft > 1.5 )
a) Australia, Finland, Netherlands, Norway b) Australia, France, Japan c) Spain, South Africa, U.S.A, Japan d) Spain, Japan, U.S.A. e) Australia, Finland, Netherlands, Norway. f) Australia, Finland, Netherlands, Norway.
9.4 Write the simplest Boolean expressions that result in the grey area selections:
a) B or C b) A and B c) [A and B] and not C d) [B or C] and not [B and C]
8.12 - Identify the states meeting each of the following selection criteria, based on the table below: a) Smokers < 20% b) Smokers > 20% and illiteracy < 10 c) Not (non-federal taxes > 9) d) Illiteracy < 7 or income > 22,000 e) Get more federal aid than paid in taxes, and non-federal taxes > 9 f) [ Firearms deaths < 10 and income > 21,000 ] and not {smokers > 20}
a) Florida, Georgia, Iowa, Minnesota, Wisconsin. b) Iowa, Minnesota, Wisconsin. c) Alabama, Alaska, Florida. d) Minnesota, Alaska. e) Iowa, Oklahoma. f) Minnesota, Wisconsin.
