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1-
Explain the following? (6, 0.6 each)
a.
Geocoding.
Assigning geographic coordinates to points
b.
Topology.
Knowledge
about relative spatial positioning
c.
Interpolation.
To
create regular spacings from irregular data
d.
Digital Elevation Model (DEM)
A
sampled array of elevations (z) that are at regularly spaced intervals in the x
and y directions.
e.
Data reduction.
Data
reduction is necessary to:
a.
conserve space
b.
conserve time
And its applied for raster data by resampling, and vector data by thinning.
f.
Buffer zone
Region
within ‘x’ distance units from any object: point, line or polygon
g.
Edge matching.
Joining
map sheets to create a seamless layer.
h.
Slivers
The small polygons formed
unintentionally when digitizing polygons.
i.
Mislabeling
To mistakenly labeling
ground features.
j.
Rubber sheeting.
GIS
file is differentially ‘stretched’ so that tic points in file overlay
corresponding ground control points on earth’s surface
2-
What is the definition of the GIS? (1.5)
GIS
is a system of integrated computer-based tools for end-to-end processing
(capture, storage, retrieval, analysis, display) of data using location
on the earth’s surface for interrelation in support of operations
management, decision making, and science.
3-
List the major steps for data Preparation and Integration (2.5)
a-
Geocoding
b-
Data media conversion
c-
Data format conversion
d-
Data reduction
e-
Topology
f-
Rectification and registration
g-
Edge matching
h-
Image adjustment
i-
Interpolation
j-
Conflation
4-
What are the two data types used in GIS? (1.5)
a.
Spatial data.
b.
Attribute.
5-
There are two data models or structures used in GIS for the spatial
data, what are they? (1.5)
a.
Raster data model.
b.
Vector data model.
6-
What is the concept of Map Projection? And what is the
UTM? (2.5)
The concept of map projection is a method by which the curved 3D surface of
the earth is represented on a flat 2D map surface. Location on the 3D earth is
measured by latitude and longitude; location on the 2D map is measured by x and
y Cartesian coordinates. Unlike choice of spheroid, choice of map projection
does not change a location’s lat/long coordinates, only its XY
coordinates.
UTM stands for Universal Transverse Mercator, and it is a transverse
cylindrical projection. The globe is divided into 60 N/S zones, each 6° wide;
these are numbered from one to sixty going east from 180th meridian. Each zone
is divided into 20 E/W bands (or “belts”), each 8° high lettered from the south
pole using C thru X (O and I omitted).
7-
Classify map projections based on property preserved,
and based on geometric model used. (2.5)
Based on property preserved:
c.
Equal area projections.
d.
Conformal projections
e.
Equidistant projections
f.
True direction
Based on geometrical model used:
a-
Planar/Azimuthal/Zenithal
b-
Conical
c-
Cylindrical.
8-
List three spatial
measurements we can do in GIS. Explain two of them. (2.5)
a-
Distance measures
b-
Polygon area
c-
Polygon perimeter
d-
Polygon shape
e-
Volume calculation
f-
Direction determination
9-
What are the types of attribute data, give one
geological example for each type? (2.0)
1- Categorical (name):
a-
Nominal: Rock types
b-
Ordinal: Stream class
2- Numerical
a-
Interval: Earthquake magnitude
b-
Ratio: Silica percent
10-
What are the three major steps needed for raster to
vector conversion? (2.5)
1-
Skeletonizing (or thinning)
2-
Vector extraction
3-
Topological reconstruction
11-
What are the
major components of the ArcView 3.1/3.2. Elaborate in two of them. (2.0)
•
projects
– comprised of views,
tables, charts, layouts, scripts
•
view
– essentially a map
which you look at or view
– contains one or more
themes
•
themes
– layers of spatial
data with similar characteristics (e.g. streets, hydrology, capitals)
•
tables
– rows (usually
geographic locations, linked by ID to
theme features)
– columns describe
attributes (characteristics) of locations
•
chart
– business graphics to
display geographic and tabular data
•
layout
– graphic
output/screen display of views, tables, charts
•
script
– automation feature
written in Avenue which allows full customization
12-
List three statistical operations for spatial data,
explain two of them. (3.0)
1- Centroid is single point representation for a polygon.
Mean Center is single point summary
for a point distribution.
2- Standard Distance Deviation is a single unit measure of
the spread or dispersion of a distribution.
3-
Standard Deviational Ellipse.
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