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65 Cards in this Set
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33. When formis used to describe the contextual characteristics of spatial data, there arethree cases or contexts that can be used. What are these? |
1. Qualitative/Quantitative: Are the attributes for the particular feature nominal ornumerical2. SpatialContext: what is the distribution of data: discrete or continuous3. Attributescontext: derived or totals |
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33. What is the difference between qualitative andquantitative spatial data? Provide a brief explanation. |
Answer: qualitative spatial data is the ordinal andnominal level of measurement you can create maps on the basis of categories butyou can not run any statistic with this type of map. |
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33. What is the difference between discrete andcontinuous data? Provide a brief explanation. |
Answer: discreet data occurs in isolated locations or itvaries very abruptly from place to place like population, area of counties orpercentages of races in the group of population. While data that changes verygradually over a large area is called continuous temperature, slope, orprecipitation. |
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33. What is the difference between total and derived data?Provide a brief explanation. |
Answer:totals are the values of that are considered true when unit is taken as awhole. That means counts of a unit, area or perimeter. If you divide the unitinto two areas will also be divided into half. |
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33. How is temporal data used in thematic mapping? |
Answer: Temporal data are used to map and analyze thechanges that occur over the particular period of time at same location |
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33. What is nominal data? Explain. |
Answer: nominal is the first level of measurement ofattribute data that has no numerical weightage. It is used just to identifydifferent features. It is also referred to as qualitative data. (roads, riversor boundaries) |
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33. What is ordinal data? Explain. |
Answer: if data describe some sort of ranking or order itis called ordinal data. How ever it does not indicate any type of quantitativedifferences among the classes. For example, (low, medium, high) |
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33. What is interval data? Explain. |
Answer: it is the 3rd level of measurement. Itis the quantitative data and arithmetical operations are permitted. It does nothave absolute zero and zero is arbitrarily determined. Temperature in Celsiusand Fahrenheit is the good example of interval data. |
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33. What is ratio data? Explain. |
Answer. The highest level of measurement is Ratio. Zero isabsolute, zero value represent the absence of the attributes being measured.Ratio scale is used with the quantitative data. All arithmetical operations arepermitted. Weight, distance, density and elevation are the example of ratiodata |
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33. Before creating a map from a particular dataset, the GIS cartographer must determine the level of measurement associatedwith that data set. Why is this important? |
Answer: It is important to determine the level ofmeasurement because it influence how the data will be represented on map. |
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33. True or false. Arithmetical operations, suchas addition and subtraction, can be used with interval level data, but not withratio level data. |
false |
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33. What are the three dimensions, or components,of colour? List and describe each of these. |
1. Hue:hue is the name of color red, green, blue. It is the dominant wavelength in thevisible spectrum. It is very much suitable for nominal values. In GIS there arecertain cartographic conventions that are used to represent certain featureslike green for vegetation or blue for water, etc.2. Saturation:Saturation, also known as Chroma, is the intensity or purity of color. If HUEis maintained constant Saturation can be used to indicate quantitative data. Itcan be used with ordinal, ratio and interval level of measurement.3. Value:value is the number of shades that can be applied to hue. If hue is removedthan the value will show different shades of grey. Just as saturation it is useto indicate quantitative differences in a mono chromatic scale. |
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33. Keep in mind the three dimensions of colour, whatis hue? Explain. |
Answer: in three dimension of colours hue is the outsideangle of cylinder. It has the value ranging from 0 – 360. Hue will have values0, 60, 120, 180, 240, 360 with red, yellow, Green, cyan, blue, magenta. |
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33. Keep in mind the three dimensions of colour, whatis saturation? Explain. |
Answer: in three dimensional model saturation isconsidered as distance from the axis. The more the distance from the axis morethe intensity or purity of colors. If these pure colors mixed with white, theywill produce tint and saturation will decrease. |
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33. Keep in mind the three dimensions of colour,what is the value? Explain. |
Answer: in three dimensional model Value is the distancealong the axis black at the bottom with value of zero and white at the top withvalue 1 or hundered. while mixing them with black – producing shades |
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33. Derived variables, such as ratios and rates,can be used to create quantitative thematic maps. What is the differencebetween ratio and rate? Explain each of these terms. |
Answer: the number of one item (attribute value) comparedto the number of another item. For example, population density.Ratio= Number of People in a province = people persquare km Area of province in square kilometers |
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33. What is the difference between proportion andpercentage? Explain each of these terms. |
Answer: The ratio of number of 1 item in one group tototal number of items in the group. For example, proportion of Hispanics in acounty. |
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Whatis data classification? Explain |
Answer: data classification is the process in whichsimilar numeric values are group together. |
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33. List three objectives that the GIScartographer should attempt to accomplish when using data classification. |
1. To classifyor group the features with similar attributes2. Toemphasize the difference between the two groups3. Togeneralize the data in order to simplify the data analysis process33. List three important steps that should beincluded in the data classification process. |
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33. When determining the number of classes, forany given classification method, the GIS cartographer can use Sturges' formulaas a starting point. What is Sturges' formula? |
C = 1 + 3.3 * log(n)Where C is the no. of classes and n is thenumber of observation. |
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33. A GIS student would like to create a thematicmap showing population density for all the counties in the state of Georgia.The state of Georgia has a total of 159 counties. Based on Sturges' formula,how many classes should the GIS student use? |
Approximately 8 classes |
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33. What is the maximum number of classes that aGIS cartographer should use when creating a black-and-white Choropleth Map? |
Answer: 7 classes because it will be difficult to distinguishbetween more than 7 shades of grey. |
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33. What is the maximum number of classes that aGIS cartographer should use when creating a colour choropleth map? |
Answer: nine classes because it is hard to distinguishmore than 9 different colors. |
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33. What is the default classification method inArcMap? |
Natural breaks and 5 classes |
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How does the natural break classification method work? Explain. |
Answer: classes boundaries are determined by the naturalgaps or breaks between the values of feature. Values in each class tend to behomogenized. Number of features can be very different in each class.33. |
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33. How does the quantile classification methodwork? Explain. |
Answer: this classification method placesroughly same number of feature in each class. It creates a balanced graphicalrepresentation. Range of values within the clas may vary significantlyproducing heterogeneous classes. |
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33. How does the equal interval classificationmethod work? Explain. |
Answer: values are grouped together in class that classesthat have equal ranges. No of feature varies in each class. If data is normallydistributed than it will have same no of features in each class. Depending onthe distribution it is possible to end up with empty class. |
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33. How does the defined interval classificationmethod work? Explain. |
Answer:Similar to Equal Interval.User sets the class width and ArcGIS calculates the corresponding number ofclasses. In thisparticular example the class width has been set to 13.0. Consequently, thesoftware sets the upper limit for the last class to 104, regardless of theactual highest value (97.5) |
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33. Howdoes the standard deviation classification method work? Explain. |
Answer: it is theclassification method that uses the statistical property of field that isstandard deviation. The class breaks are based on standard deviation of thedata. Very good classification method for identifying typical and extremevalues. |
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33. How does the nested means classificationmethod work? Explain (see your textbook - Chapter Five). |
Answer: classification method used on thestatistical calculations. The arithmetic mean of the entire array is thedividing point of the first two classes. Classes are further divided bycalculating the mean of each subgroup |
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33. What are two types of tables that can be usedin ArcGIS? |
Answer: Stand Alone table, Attribute Table |
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33. Which type of table is associated with specialdata? |
Answer: Attribute Table |
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1. What is atable join? Explain. |
a. Joins aretemporary relationships between tablesb. Tables mustshare a common fieldc. Treats thetwo tables as a single tabled. Original storeddata is not affected |
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1. What is atable relate? Explain. |
a. Similar to ajoin except that:b. The tablesremain separate.c. When recordsare selected in one table the related records may be subsequently selected inthe other table. |
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1. What types ofcardinality are required for a table join? |
a. One to One(Country to prime minister), One to Many (states to cities), Many to One(cities to states), Many to Many (students to classes) |
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1. What types ofcardinality are required for a table relate? |
a. Selectedresult must be related to corresponding records. A selection in the first table(States) will result in a selection of the correspond- ding records in therelated table (Congressional Districts). The relate must be"activated" for this to occur. |
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1. Why is it notpossible to perform a table join when the cardinality between two tables isone-to-many? |
a. Thissituation violates the rule of joining! Only one record in the source table canbe joint to the record in the destination table. Table join is ambiguous: atable relate must be used instead. |
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1. What is theRule of Joining? Explain. |
a. Each recordin the destination table must match one and only one record in the sourcetable. |
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1. When workingwith ArcGIS, what is a one-to-one cardinality? In your answer, include theterms "destination table" and "source table”. |
a. One record inthe destination table matches exactly one record in the source table. We callthis a cardinality of one-to-one. |
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1. When workingwith ArcGIS, what is a many-to-one cardinality? In your answer, include theterms "destination table" and "source table”. |
a. Many recordsin the destination table match one record in the source table. We call this acardinality of many-to-one. |
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1. When workingwith ArcGIS, what is a many-to-many cardinality? In your answer, include theterms "destination table" and "source table”. |
a. One originobject can relate to multiple destination objects and, conversely, onedestination object can relate to multiple origin objects. For example, a givenproperty may have many owners, and a given owner may own many properties. |
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1. What does thesummarize function do? Explain. |
a. Summarize isa powerful function similar to the "Group By" function in relationaldatabases. |
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1. What are theresults of the summarize function? |
a. This functionwill aggregate a group records that have the same attribute value (must be anominal field) into a single record. Statistics can be calculated on differentfields for each group of records. The results of the Summarize function arestored in a standalone attribute table. |
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1. When workingwith numeric health fields, what are six statistics that can be calculated whenusing the summarize function? |
a. Minimumb. Maximumc. Averaged. Sume. StandardDeviationf. Variance |
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1. What is afeature? |
a. A spatialobject composed of one or more x-y coordinate pairs and having or moreattributes in a single record of an associated table |
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1. What is anattribute? |
a. informationabout map features stored in columns of a table |
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1. What is afeature class? |
a. a set ofsimilar objects with the same attributes stored together in a spatial data file |
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1. What is thedifference between a feature class and a feature data set? |
a. featuredataset stores multiple feature classes |
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1. What isspatial accuracy (also known as geometric accuracy)? |
a. the accuracywith which the shape and position of features are represented |
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1. What isthematic accuracy? |
a. the degree towhich attribute values represent the true properties of the real world |
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1. What is thedifference between precision and accuracy? Explain. |
a. Accuracymeans getting a result that is close to the real answer. Precision meansgetting a similar result every time you try. Think of shooting at a target:Being accurate means you hit the bull's eye. Being precise means hitting thesame spot on the target every time. |
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1. What is anArcMap document? What type of data does it store? |
a. The file thatcontains one map, its layout, and its associated layers, tables, charts, andreports. Map documents can be printed or embedded in other documents. Mapdocument files have a .mxd extension. |
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1. What arethree types of geodatabases that can be used in ArcGIS? |
a. FileGeodatabases, Personal Geodatabases, and SDE Geodatabases |
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1. What is theRGB colour system? When should a GIS cartographer employ this coloursystem? |
a. A color modelthat uses red, green, and blue, the primary additive colors used to displayimages on a monitor. RGB colors are produced by emitting light, rather than byabsorbing it as is the case with ink on paper. Adding 100 percent of all threecolors results in white |
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1. What is theCMYK colour system? When should a GIS cartographer employ this coloursystem? |
a. A color modelthat combines the printing inks cyan, magenta, yellow, and black to create arange of colors. Most commercial printing uses this color model. |
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1. What is thedifference between the data types "short integer" and "longinteger”? |
a. If you justneed to store whole numbers, such as 12 or 12,345,678, specify a short or longinteger. Short Integer:Numeric values without fractional values within specificrange; coded values. Long Integer: Numeric values without fractional valueswithin specific range |
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1. What is thedifference between the data types "float" and “double"? |
a. If you needto store fractional numbers that have decimal places, such as 0.23 or1234.5678, specify a float or a double. Float: Numeric values with fractionalvalues within specific range. Double: Numeric values with fractional valueswithin specific range |
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1. What does aBLOB stand for? When should you use this data type? |
a. Acronym for binary large object. A large block of data, such asan image, a sound file, or geometry, stored in a database. The database cannotread the BLOB's structure and only references it by its size and location. Thedata type of the column in the database that stores binary large objects. |
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1. What is themost appropriate data type for calculating percentages? Why should you use thisdata type, as opposed to using other numerical data types? |
a. A float canhave a precision of 0–8 numbers with a scale of 0. Floats are used to storesimple decimal numbers such as percentages. |
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What is the difference between a spatial queryand an attribute query |
a. Spatialqueries, such as finding parcels of land that intersect a 100-year floodplaincan be accomplished through QueryTask by setting the ‘geometry’ and optionallythe ‘spatialRelationship’ properties on the Query object. Attribute queries canbe performed against layers and tables exposed by an ArcGIS Server instance.The ‘where’ and ‘text’ properties are used to define attribute queries. Anylegal SQL ‘where clause’ can be used in the ‘where’ property. |
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1. List threespatial operators that can be used with spatial queries. |
a. Containment,Intersection, and Intersection |
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1. What iscontainment? Explain the properties of this spatial relationship. |
a. Containmenttest whether one feature includes another. For instance in they are withinor completely within a determined boundary |
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1. What isintersection? Explain the properties of this special relationship. |
a. Intersectionis the most generic operator and returns any feature in A that touches,crosses, or overlaps any part of a feature in B. |
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1. What isproximity? Explain the properties of this special relationship. |
Proximity tests how close features in A are tofeature B. Within a distance for instance is a generic test. |
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1. Please study all the chapter review questions inChapter 1 (page 26)2. Please study all the chapter review questionsin Chapter 4 (page 122)3. Please study all the chapter review questionsin Chapter 6 (page 189)4. Please study all the chapter review questionsin Chapter 8 (page 244) |
1. Please study all the chapter review questions inChapter 1 (page 26)2. Please study all the chapter review questionsin Chapter 4 (page 122)3. Please study all the chapter review questionsin Chapter 6 (page 189)4. Please study all the chapter review questionsin Chapter 8 (page 244) |
