GEOG 363 - Homework & Exam Questions

(T/F) Georeferencing is the process of transforming locations from image-space to real-world space.

True

(T/F) Geospatial data refers to data describing both locations & characteristics of spatial features.

True

(T/F) In vector data model, a polyline feature has one dimension, besides the property of a location, a polyline feature also has the length property.

True

(T/F) Land surveying & remote sensing are examples of primary data capture approach.

True

(T/F) Scanned digital files are raster datasets.

True

An affine transformation requires a minimum of ____ control points.

3

What's the speed of electromagnetic energy (like the GPS signal)?

300,000,000 meters/second

What is a datum?

A mathematical model of earth, defining the GCS using an appropriate ellipsoid

(T/F) The map scale of 1/10000 is larger than the map scale of 1/1000.

False

GPS

Global Positioning System

What are the 3 map projection surfaces?

- Cylindrical - Azimuthal - Conic

Which of the following phenomena can be better represented by raster data model?

- Distribution of a chemical pollutant in Columbia, SC - Soil moisture of a land parcel

Regarding map projections, which statements are true?

- On a projected map, there is no distortion along the standard line - Conformal projections preserve local angles and shapes - Equivalent projection is good for mapping quantities, e.g., population density, because it preserves the area.

GPS reached a full operational status in the year ______.

1995

DEM

Digital Elevation Model

DRG

Digital Raster Graphic

What is the laser distance formula?

Distance = 1/2 travel time x 3 x 10^8m/s ex: 1/2(3x10^8m/s)x(0.000025s) = 1/2x7500 = 3750m

__________ is measured from GPS.

Ellipsoidal height

In georeferencing, the two equations: X = Ax + By + C and Y = Dx + Ey + F are used to ________

Establish a relation between image-space & real-world space

(T/F) A polygon feature is made of connected, closed, lines. These lines can be self-intersected.

False

(T/F) An affine transformation requires a minimum of two control points.

False

(T/F) GPS uses the concept of triangulation for determining the X-Y-Z position of observations.

False

(T/F) Global Positioning Systems (GPS) is based on triangulation to determine the position.

False

(T/F) Projected Coordinate System (PCS) uses latitude & longitude to define locations on the earth

False

(T/F) Scanned digital files (such as the 1904 Lake Murray quadrangle used in the lab) are vector datasets.

False

(T/F) The value range of latitude is from 180 degree West (-180°) to 180 degree East (180°).

False

List 3 common datums used in the US

North American Datum 1927 (NAD27) North American Datum 1983 (NAD83) WGS 1984 (WGS84)

List at least 3 basic map elements.

North arrow Legend Title Scale bar

(T/F) A GIS is able to capture, store, query, analyze, & display geospatial data, but analyzing relationships is unique to GIS.

True

(T/F) Accuracy is the degree of closeness of measurements of a quantity to its actual (true) value.

True

(T/F) Control points are known locations for a physical feature that can be identified.

True

(T/F) Distortions cannot be avoided when projecting the earth surface to a flat map no matter what kind of map projection is used.

True

(T/F) Ellipsoidal height is the height above the ellipsoid.

True

(T/F) For complex problems, we may need to combine multiple spatial queries & attribute queries to get the answer.

True

(T/F) GIS is a system designed to capture, store, query, analyze, & display geospatial data

True

(T/F) Generally spatial query is more time consuming than attribute query.

True

(T/F) Primary data capture is the process of abstracting & recording the geographic position and attributes of features from their native source.

True

(T/F) Raster data model is good for representing the environmental phenomena such as precipitation & earth surface elevation.

True

(T/F) The GPS was developed & is maintained by the US Department of Defense.

True

(T/F) The acronym DBMS means Databased Management System.

True

(T/F) Topology captures the spatial relationships between geographic features, which is important for spatial analysis.

True

(T/F) Total station can measure both angles & distances.

True

(T/F) Triangulation is a technique for determining position from angles, while trilateration is used to determine position from range (or distance).

True

(T/F) Vector data model & raster data model are two common data models in GIS.

True

DLG

Digital Line Graph

__________ is the most common transformation method in georeferencing.

Affine

Explain Zenith angle

An angle measured from a vertical reference point

Relative position in geographic space can be determined using triangulation or trilateration. Triangulation is based on ________ measurement.

Angle

Map design principles do NOT include ______________.

Colorful

What is attribute data in GIS?

Data that describes the geographic characteristics of features, aspatial data

Explain the difference between spatial query & attribute query.

Spatial query uses the spatial relationship between features as criterion, implemented using spatial equivalents of DBMS queries. Attribute query uses the aspatial characteristic of a feature as criterion, implemented using DBMS query

Provide the full name of SQL

Structured Query Language

When converting the coordinates of 30° 3' North, 118° 15' West to decimal degrees in GIS format, which of the following is correct?

(-118.25, 34.05)

What are the 3 major approaches to collecting geospatial data?

1. Primary data capture - in the field - land survey, GPS to map coordinates - touch features 2. Primary data capture - capture data remotely - remote sensing - without touching features 3. Data conversion - converting hardcopy maps to digital form or extract vector from raster - scanning map

Explain the difference between geo-relational data structure & object-based data structure

Geo-relational - stores geometries & attributes separately in a split system Object-based - stores geometries & attributes in a single system

Explain what a GIS is

Geographic Information System able to capture, store, query, analyze, & display geospatial data. You can use GIS to analyze your captured/stored data & display it on a map

Which of the following is the closest approximation of the Earth's shape?

Geoid

Orthometric height is the height above the _____________.

Geoid (mean sea level)

Which of the following geographic features can be better represented as polygons?

Land parcels

When analyzing the geographic distribution of a chemical pollutant, which of the following GIS data models should you use?

Raster

Georeferencing is the process of transforming locations from image-space to __________.

Real-world space

Provide the full name of RMSE

Root Mean Squared Error