GIS 201 Midterm Exam Review

Card Set Information

GIS 201 Midterm Exam Review
2011-10-16 11:20:00
spatial joins projections geodatabases chapters 11 14

Terms and concepts having to do with spatial joins.
Show Answers:

  1. When must summarized joins be used?
    • A. With 1-to-many joins.
    • B. With many-to-1 joins.
    • C. With 1-to-1 joins.
    • D. B and C only.
    • A. The answer is 1-to-many.
  2. When must simple joins be used?
    • A. With 1-to-1 cardinality.
    • B. With many-to-1 cardinality.
    • C. With 1-to-many cardinality.
    • D. A and B only.
    • D. The answer is D.
  3. What questions to ask when setting up a spatial join?
    • 1. What should the final output layer/table look like?
    • 2. What is the destination layer?
    • 3. Should a distance join or an inside join be used?
    • 4. What is the cardinality of the join?
    • 5. Should a simple join or a summarized join be used?
  4. When using the append tool, do the input layers have to have the same feature type?
    • A. Yes
    • B. No
    • C. Only if one layer is a polygon layer.
    • D. Only if one layer is a point layer.
    • A. The answer is yes.
  5. Is overlapping of layers permitted with the append tool?
    • A. Yes
    • B. No
    • C. Only if the layers are polygons.
    • D. Only if the layers are points.
    • A. The answer is yes.
  6. What is a spheroid?
    An oblong sphere with a major and minor axis used to model the bulge of the earth at the equator.
  7. What is a geoid?
    A measurement of the earth's radius with respect to a datum (often the sea level, but varies).
  8. What is a datum?
    The combination of a spheroid and the location where its center is placed. To achieve the best accuracy on a map, the spheroid is moved until the geoid at the area being mapped corresponds best with the spheroid surface.
  9. What is an earth-centered datum?
    A datum in which the center of the spheroid coincides with the center of the geoid.
  10. What is a transverse projection?
    A cylindrical projection in which the cylinder is rotated sideways such that it is tangent to the earth along a line of longitude.
  11. What is an oblique projection?
    One in which the tangent is at an angle to lines of longitude.
  12. What is an azimuthal projection?
    One in which a plane is placed tangent or secant to a sphere.
  13. What are other names for azimuthal projections?
    Stereographic or orthographic.
  14. What are the parameters used to describe map projections?
    • 1. Central meridian
    • 2. Latitude of origin
    • 3. Standard parallel(s) -- line(s) of tangency or secancy
    • 4. False easting and false northing
  15. What is a georeferenced raster?
    One that has been assigned a real-world coordinate system.
  16. What 3 things does a spatial reference include?
    • 1. The coordinate system
    • 2. The X/Y domain
    • 3. The resolution
  17. What is the X/Y domain?
    The range of allowable x-y values that can be stored in a feature class.
  18. What is the extent of a data layer?
    The range of x-y coordinates of the features actually in the feature class.
  19. What are the 3 types of geodatabases?
    • 1. Personal
    • 2. File
    • 3. SDE
  20. What type of geodatabase is:
    -Designed for individuals or small workgroups.
    -Stored in a single Microsoft Access file.
    -Limited to 2 GB and works only in the Windows operating system.
    Personal geodatabase.
  21. What type of geodatabase does the following describe:
    -Designed for individuals or small workgroups.
    -Stores each data set as a separate file within a system folder.
    -Each file can be up to one terabyte in size.
    -Works on various operating systems.
    File geodatabase.
  22. What type of geodatabase does the following describe:
    -Stores data within one of several commercial relational database management systems, such as Oracle, SQLServer, or IBM Informix.
    -Can be accessed by many users simultaneously.
    SDE geodatabase.
  23. What are the two types of attribute domains?
    Range (specifies highest and lowest values and lets the values take any number in between) and coded (only allows values from a certain list).
  24. On what kind of data must subtypes be based?
  25. Do features in a feature dataset have to have the same spatial reference?
  26. What is a feature dataset?
    A collection of feature classes that are related to each other in some way.
  27. What are some of the advantages of geodatabases?
    • Can store topological relationships between features, like coverages;
    • Simpler in construction and more robust in general usage than coverages;
    • Harder to corrupt than shapefiles;
    • Automatic tracking of lengths and areas for features;
    • Behavior and validation rules.
  28. What are the 3 different projections used by the State Plane Coordinate System?
    • Lambert Conformal Conic
    • Transverse Mercator
    • Oblique Mercator
  29. Conic projections typically preserve ________ and ________ at the expense of ________ and ________.
    area; distance; direction; shape
  30. Cylindrical projections typically preserve ________ and ________ at the expense of ________ and ________.
    shape; direction; area; distance.
  31. As a rule, what do azimuthal projections preserve?
    Area or distance at the expense of direction or shape.
  32. What type of projection is Mercator?
  33. Rows in a table are also known as ________.
  34. Columns in a table are also known as ________.
  35. What are the 4 types of spatial joins?
    • Simple inside (in which county is each school?)
    • Summarized inside (how many schools are in each county?)
    • Simple distance (Which attraction is closest to each hotel? How far?)
    • Summarized distance (How many attractions are closer to any hotel than to any other?)
  36. What is geometric accuracy usually a function of?
    The original scale at which data are collected and of how they were obtained.
  37. What is precision?
    • The number of significant digits used to record a measurement
    • OR
    • The statistical variation of a repeated single measurement.
  38. Which of the following are shapefiles?
    • A. Spaghetti data models
    • B. Topological data models
    • C. Usually spaghetti, but sometimes topological
    • D. Usually topological, but sometimes spaghetti
    • A. The answer is spaghetti.
  39. How do features relate to feature classes and feature datasets?
    Features are the 3 basic objects of the vector model (points, lines, and polygons). Like features are grouped into data sets called feature classes, and feature datasets contain multiple feature classes that are in some way related to each other.
  40. What is the difference between geometric accuracy and thematic accuracy?
    Geometric accuracy refers to the x-y values, while thematic accuracy refers to the exactness of attributes (how close the population figures are to reality, etc.)
  41. What 3 kinds of data are there?
    • Nominal
    • Categorical
    • Numeric
  42. What are ordinal data?
    Data that are grouped by rank based on some quantitiative measure (e.g., cities can be small, medium, or large).
  43. What kind of data have a meaningful zero point such that zero indicates the absence of the thing being measured?
  44. What kind of data have a regular scale but not a meaningful zero point?
  45. What is the stretched display method?
    A display method for rasters that can improve the display of normally distributed values by ignoring the tails of the distribution. The method scales the image values to a color ramp with 256 shades.
  46. What is the classified display method?
    A display method for rasters that divides the values into a small number of bins and a color ramp is chosen to assign the colors to each bin.
  47. What data is the equal-interval method best used on?
  48. What data is the quantile method best used on?
    Linearly-distributed data.
  49. What classification methods are there?
    • Natural breaks (Jenks)
    • Equal interval
    • Defined interval
    • Quantile
    • Geometric interval
    • Standard deviation
    • Manual class breaks
  50. What type of grid shows latitude and longitude markings?
  51. What type of grid shows the map units present in the coordinate system?
    The measurement grid.
  52. What type of grid shows the letters and numbers delineating each grid square?
    reference grid
  53. What is the reference scale?
    The scale at which text or symbols appear at their assigned size.
  54. True or false: once a field definition is set, it cannot be changed.
  55. When defining a number field for a shapefile, what is precision?
    storage width
  56. When defining a number field for a shapefile, what is scale?
    The number of decimal places.
  57. How many significant digits can a single-precision field store in the mantissa?
    Up to 8.
  58. What fields should never be altered by the user?
    • Feature ID (FID)
    • Object ID
    • Shape
  59. True or False: After a query is performed and a selection made, any subsequent operation on that layer only operates on the selected set of features.
  60. True or False: ArcToolbox can be used in ArcMap but not in ArcCatalog.
    False; it can be used in either.
  61. What are topology rules for?
    They establish how features should be spatially related.
  62. What is scale?
    Ratio of distance on map to distance on ground.
  63. What is large scale and what is small scale?
    • Small scale: large denominator = small fraction; large area shown.
    • Large scale: small denominator = large fraction; small area shown.
  64. How does one estimate precision from scale?
    Map scale / 1000 gives an approximate precision in feet for a 1-pt-thick line.
  65. True or false: coverages can be edited in ArcGIS.
  66. True or False: Spaces are OK in file and folder names.
    False; allowed but a bad idea.
  67. What are the 5 questions to consider when designing a map?
    • Who will be using it?
    • Under what circumstances will they use it?
    • Is the map likely to be copied or faxed?
    • What objectives should the map achieve?
    • How sensitive is the map information?
  68. How many zones are there in the UTM system?
    60, each 6 degrees wide.
  69. True or False: SQL is nearly always case-sensitive.
  70. Is cardinality destination-to-source or source-to-destination?
  71. How many characters can there be in a field name?
    Up to 13.
  72. True or False: Can a field name start with anything but a letter?
  73. True or False: Text data is always stored in ASCII format.
  74. True or False: Numeric data can only be stored in binary format.
    False; can be either ASCII or binary.
  75. In a shapefile, can a field named AREA alwasy be relied upon to be correct?
    No; fields in shapefiles are not automatically updated.
  76. True or False: In a coverage, a field named AREA is updated automatically.
  77. In what units is Root Mean Square (RMS) error measured?
    The map units.
  78. What projections are preferred for north-south-oriented areas?
  79. What projections are preferred for east-west-oriented areas?
  80. When are features considered to intersect?
    When a feature touches, crosses, or overlaps another feature.
  81. What is the inverse of within?
  82. Why are spatial joins not always the way to go and overlays must be used?
    Some features do not exactly line up with others--for example, a road may lie in more than one land use type. A summarized join doesn't work with categorical data.