QUESTIONS WITH ANSWERS GRADED A+
◍ Perimeter:.
Answer: The total measure of the length of the outside of a polygon
◍ Geophysics.
Answer: Focus:Earth's physical propertiesMagnetic, gravity, seismic
fieldsContribution to GIS:Subsurface modelingHazard analysis
◍ Random Sampling.
Answer: Selecting point locations from random numbers. Random sampling
reduces the chances of bias because it's unlikely to match a pattern in the
landscape. The downside of random sampling is that it does nothing to
distribute samples in areas of high variation.
◍ Hydrologic Models.
Answer: Model water flow. Hydrologic models often use DEMs and map
algebra.
◍ Mixed Pixel.
Answer: A condition whereby more than one category of object is present
within a single grid cell.
◍ OGC File Base Standard Include.
Answer: Keyhole Markup Language (KML)Keyhole Markup Language
zipped (KMZ)Geographic Markup Language
(GML)Geo-packageGeoTIFFLaser(LAS)
◍ Spatial Accuracy.
Answer: How geographically close data is to its true value
◍ Digital Surface Model (DSM).
Answer: A type of DEM that represents a maximum value within a grid cell,
, thereby recording the tops of buildings, trees and other objects.
◍ Time values.
Answer: Can be stored in a data, string, or numeric fields
◍ Spheroid.
Answer: a sphere-like but not perfectly spherical body. Different spheroids
are used to represent different parts of the Earth because they fit different
parts of the Earth better.
◍ Object Relational Data Model.
Answer: Combines elements of relational and object-oriented database
models. Examples of object relational data models: SQL Server, Oracle,
PostgreSQL, and the Geodatabases.
◍ Data Quality.
Answer: The overall suitability of a dataset
◍ Area.
Answer: The amount of space a polygon contains.
◍ Tessellation.
Answer: The covering of a surface, often a plane, using one or more
geometric shapes, called tiles, with no overlaps and no gaps. Rasters, DEMs,
and TINs are tessellations.
◍ Best projection geometry for global/equatorial maps?.
Answer: Cylindrical.
◍ Point.
Answer: A coordinate location described by X, Y, and sometimes Z values.
X defines longitude, Y defines latitude, and Z defines elevation.
◍ Raster Resampling.
Answer: Raster and images can be resampled to higher or lower resolutions.
◍ How many standard parallels do tangent cylindrical and conical projections
have?.
Answer: One standard parallel.
,◍ Cylindrical Projections.
Answer: Project the Earth onto a surface of a cylinder that is then unrolled
as a plane. Cylindrical projections preserve area and shape. Distance gets
distorted on upper and lower regions of the map.
◍ What is an equidistant projection?.
Answer: Preserves distance from specific points or lines.
◍ Topological Relationships.
Answer: Spatial relationships that characterize the relative position of spatial
objects.
◍ American National Standards Institute (ANSI).
Answer: The US member agency to the international Standard Organization.
It made the Spatial Data Transfer Standard (SDTS), which is being replaced
with the Geographic Markup Language.
◍ Relevance.
Answer: Same as fitness for use
◍ Topological relationships include:.
Answer: EqualsDisjointedIntersectsTouchesContainsCoversWithinCrossesOverlaps
◍ Discrete Data.
Answer: Only occurs at specific locations and has well-defined boundaries.
Discrete data is usually in vector format. Discrete data is also called
categorical or discontinuous data.
◍ Spatial Model.
Answer: A framework for expressing mechanisms of geographic process
and designing analytical workflows to understand these processes.
◍ Metadata.
Answer: Document the who, what, where, when, why and how of a data
source. Metadata can include information about the content, source, lineage,
methods, developer, coordinate system, extent, structure, spatial accuracy,
attributes and responsible organization for spatial data.
, ◍ Infrastructure for Spatial Information in Europe (INSPIRE).
Answer: The organization that oversees spatial data standards in Europe
◍ The National Geodetic Survey (NGS).
Answer: Defines, maintains, and provides access to the National Spatial
Reference System. It provides a framework for all positioning activities in
the US. It's administered by the National Oceanic and Atmospheric
Administration (NOAA). They maintain the benchmark for the High
Accuracy Reference Network (HARN)
◍ International Standards Organization (ISO).
Answer: Maintains international standards for GIS methods, tools and
services for data management through ISO Technical Committee 211
(ISO/TC 211).
◍ Intersection.
Answer: A point common to multiple lines or surfaces.
◍ 5 Steps in Applying the NSSDA.
Answer: 1. Identify test points2. Identify true values3. Collect positional
measurements4. Calculate the positional error and summarize in a standard
accuracy statistic5. Record the accuracy statistic in a standardized form
◍ Continuous Ranks.
Answer: Vary along scale
◍ WGS 1984.
Answer: A spheroid used for WGS84 reference frames. Used for GPS
◍ Network Attributes.
Answer: DirectionWeight (cost, time, distance)Capacity
◍ Equivalent projection:.
Answer: Preserves area
◍ Systematic Sampling.
Answer: Samples are taken from fixed intervals. The whole study is equally
sampled. Systematic sampling may introduce a bias in the data if there is a