GIS Final Exam Practice Flashcards

Spatial Resolution

(Is a measure of the smallest...) 

• Describes how detailed an image is; smallest object or distance a sensor can distinguish 

Spectral Resolution

(Is the number and dimension...) 

• Refers to the number and width of a wavelength bands a sensor can detect 

Temporal Resolution

(Of remote sensing systems...) 

• Refers to how often a sensor captures imagery of the same location 

Radiometric Resolution

(Is defined by sensitivity of...)  

• Measures a sensors sensitivity to differences in brightness (color depth) 

Which of the following sensors uses a highly focused beam of light, and has been... discover the ruins of ancient cities under rain forest canopies  

Light Detection and Ranging (LiDAR) sensor 

Which of the following is NOT a raster data format?  

Shapefile  

A network of streets in vector-based GIA is represented as a polyline. If we choose to represent this data with raster... we will encounter the issue of “fat lines” 

True  

Radar sensors were used in 2000 on a space shuttle mission to produce a global DEM that is still used by many today 

True  

• SRTM used radar sensors on space shuttle to produce (DEM) 

Formula to calculate Normalized Difference Vegetation Index (NDVI) is 

Near infrared - RED/ Near infrared + RED 

Which of the following map elements usually has the biggest font size on a map? 

Title

Generally, the higher the temporal resolution requirement of remotely sensed image (monitoring hurricanes... half-hour), the lower the spatial resolution requirement (NOAA GOES weather satellite records images... to 8 x 8 km pixels) 

True 

• Higher temporal resolution (e.g., hurricane monitoring) usually means lower spatial resolution (e.g., GOES: 8×8 km pixels) to allow frequent, wide-area coverage 

Which of the following is an advantage of the vector data model over the raster data model?   

Vector datasets are generally more suitable for representing manmade features such as buildings, streets, and counties 

For a certain raster data set, spatial resolution is 250 x 250. How many pixels will be required at this resolution to represent an area of 10 square kms 

160 

1. Spatial resolution: 250 × 250 meters per pixel 

2. Pixel area = 250 × 250 = 62,500 m² = 0.0625 km² 

3. Area to represent: 10 km² 

4. Number of pixels needed = 10 / 0.0625 = 160 

Georeferencing a given dataset requires 2D information whereas orthorectification requires 3D information  

True  

1. Georeferencing aligns data to a coordinate system using 2D control points (X, Y). 

2. Orthorectification corrects image distortions caused by terrain and sensor angle using 3D data (X, Y, and elevation/Z). 

Pieces of information that provide description of features in GIS are called: 

Attributes 

Aligning geographic data to a known coordinate system so it can be viewed, queried, and analyzed with other geographic data is known as 

Georeferencing 

In the context of GIS, capturing map data by tracing lines from a map by hand is called digitization  

True 

Satellite-based passive remote sensing devices collect images of reflected or emitted energy from portions of the electromagnetic spectrum  

True 

If you acquire LANDSAR image, it will probably be a series of seven or eight stacked raster files, each representing the reflectance values of the scene at a different wavelength range (Band) 

True 

What questions can GIS help answer 

All of the above

1. What if this happened? (what if modeling) 

2. How is this thing changing? 

3. Where is it? 

4. What spatial patterns exist? 

5. What is it like?  

Map showing population density distribution:

Thematic map 

Map showing location of places, streets and landmarks:

Atlas map

Map data source:

Metadata of a map 

Scale bar

Essential cartographic element  

The tabular data associated with individual vector data (shapefiles) is called 

Flat file 

The full name of the vector 3D data format TIN is

Triangulated Irregular Network  

Introduction of computers in mapmaking has heavily reduced the time it takes to go through the “design cycle” of a map  

True 

The individual cell value of a raster file is known as a

Digital number 

Red wavelength

620-680nm

Blue wavelength

410-490nm 

Green wavelength

540-590nm 

Near Infrared wavelength

780nm-900nm 

The coordinates for location A (10,000 m E, 60,000 N) location B (6,500 m E, 41,000 N) are provided to you. The Euclidean distance between the two locations will be 

None of these – 19,320 m 

In GIS point data has how many dimensions 

None of these –0 dimensions  

The average distance of one degree of latitude on the surface of the earth is 

111.111 km or (111,111 meters) 

Which statement about UTM is false?

The UTM system covers the whole planet in one consistent metric system of coordinates

The Mercator projection preserves local shape and point-to-point direction. This property is called  

Conformality  

642306m E 4853658m N Zone 15

Universal Transverse Mercator 

43°48’48’’ N, 93°13’59’’ W

Geographic Coordinate System 

1128064.83 feet E, 2129751.93 feet N. WI, South Zone

State Plane Coordinate System  

15TWC873130

Military Grid Reference System 

A school occupies a rectangular plot of land that measures 8 cm by 3 cm on a map where 100 m running track measures 2 cm. What will be the actual land area occupied by the school?  

60,000 sq m 

1. Scale factor= 100m/ 2 cm = 50m/cm 

2. Actual dimensions 

   • Length: 8cm X 50 =400 

   • Width: 3cm X 50 =150 

3. Area= 400m x 150m = 60,000 sq m 

Most commonly uses topographic map in the USA are at what map scale 

1: 24,000 

Which of the following serves as the earth's referencing elevation when “sea level” is inadequate. (Which it is in many cases because the sea is not everywhere and because the sea can be affected by wind or weather)? 

Geoid  

A datum only gives you a shape while a spheroid gives you a location of specific places on that shape 

False 

In an ellipsoid model of earth, the diameter of earth through the poles is larger than the diameter through the equator 

False 

Raster imagery with a 6-bit radiometric resolution can show how many values 

64 values 

For raster imagery with a single precision float data type, each pixel requires 4 bytes of space. This raster imagery has 6 bands, and each band has 200 rows and 400 columns. How much drive space will be required to store this imagery? 

None of these- 1.83 MB 

1. Data type: Single precision float = 4 bytes per pixel 

2. Image size: 200 rows × 400 columns = 80,000 pixels per band 

3. Bands: 6 

4. Total pixels = 80,000 × 6 = 480,000 pixels 

5. Total storage = 480,000 pixels × 4 bytes = 1,920,000 bytes 

6. 1,920,000 bytes/ 1024 X 1024= 1.83 bytes 

Most earth observing remote sensing satellites are in geostationary orbit whereas GPS satellites are in sun synchronous orbit 

False 

• Most in sun-synchronous  

The Universal Transverse Mercator (UTM) coordinates of a position in northern hemisphere states that its northing is 3,546,453 m N and easting is 400,765 m E. How far is this position from south pole

13,546,453 m 

1. UTM northing starts at 0 meters at the Equator. 

2. The distance from the South Pole to the Equator is about 10,000,000 meters. 

3. Northing = 3,546,453 m (distance north of the Equator) 

4. 10,000,000m (equator to south pole) + 3,546,452m (equator to location) = 13,546,453m 

Which of the following data types can contain decimal precision 

Float 

Conceptual generalization changes the geometry of features in GIS while graphic generalization changes the map legend 

False 

1. Graphic= changes geometry 

2. Conceptual= What features are shown, not shape