CP6514_Practice Exercise 4
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Maribeth Price, 2020: Mastering ArcGIS Pro – Second Edition. NY: McGraw Hill
Practice Exercise #4
1. Examine the coordinate system for the streets feature class in the Austin geodatabase. What is
the name of the coordinate system? Is it projected or unprojected? What are the map units?
Projection parameters of the feature classes in the Austin geodatabase are as follows:
Name of the coordinate system: NAD 1983 StatePlane Texas Central;
Whether or not it is projected: Yes (Projected);
Map unit: US Feet
2- What is the name of the projection (not the coordinate system) used by the feature classes in
the Oregon geodatabase? What are the central meridian and the standard parallel(s)? Does it
use the equator for the latitude of origin?
Projection parameters of the feature classes in the Oregon geodatabase are as follows:
Name of Projection: Lambert Conformal Conic
Central meridian: -120.5
Standard parallel (1): 43.0
Standard parallel (2): 45.5
No. Latitude of origin: 41.75
3- Determine the coordinates of the summit of Mount Rainier, Washington, in (a) degrees-
minutes-seconds, (b) UTM Zone 10 (in meters), and (c) Washington State Plane South (in US
feet). Use the NAD 1983 datum in all cases.
The coordinates of the summit of Mount Rainier, Washington, with different coordinate standards
are as follows:
(a)
Degrees-minutes-seconds: 46°51'11"N 121°45'37"W
(b)
UTM Zone 10: 5,206,425 meters Northing, 562,653 meters Easting
(c)
Washington State Plane South: 17,101,540 feet Northing, 767,823 feet Easting
4- Compare the projection parameters of the North America Equidistant Conic and the USA
Contiguous Equidistant Conic predefined coordinate systems. Explain the reason for the
differences.
USA Contiguous Equidistant Conic and North America Equidistant Conic share the same central
meridian, GCS, and Datum. However, they have different standard parallels and the latitude of
origin. It reflects the fact as follows:
USA Contiguous Equidistant Conic acknowledges the onshore United State, which excludes
Alaska, as a coordinate system boundary, whereas;
North America Equidistant Conic includes the North American subcontinent, which
includes the United States, Alaska and Canada as a coordinate system boundary.
Projected Coordinate System
Projection parameters
North America
Equidistant Conic
USA Contiguous
Equidistant Conic
Central Meridian
-96
Standard Parallel 1
20
33
Standard Parallel 2
60
45
Latitude of Origin
40
39
GCS / Datum
NAD 1983 / D North American 1983
5- Examine the standard parallels and the latitude of origin of the Africa Lambert Conformal
Conic predefined coordinate system and state them. Predict whether any areas of Africa have
negative y coordinates in this projection. Why or why not?
Africa Lambert Conformal Conic has the following projection parameters:
Projected Coordinate System
Projection parameters
Africa Lambert Conformal Conic
Standard Parallel 1
20.0
Standard Parallel 2
-23.0
Latitude of Origin
0.0
GCS
WGS 1984
Datum
D WGS 1984
Given the above facts, some areas of Africa which locates south to the equator line (latitude of
origin) will have negative y coordinate.
6- Is the Africa Lambert Conformal Conic projection a tangent or a secant projection? How can
you tell?
Africa Lambert Conformal Conic has 2 standard parallels which shows it’s a secant projection.
7- What datum is used for Africa Lambert Conformal Conic coordinate system? Why is it
different from the one used for the North America Equidistant Conic coordinate system?
Africa Lambert Conformal Conic coordinate system utilizes D WGS 1984 datum, an
earth-
centered datum
, to best represent the approximate shape of the African continent. As the African
continent is located close to the equator, it can be best projected by D WGS 1984 which sets its
latitude of origin as 0, where the equator line exists.
On the other hand, North America Equidistant Conic coordinate system utilizes D North
American 1983 datum, a
local datum
, to best represent the approximate shape of the whole North
American continent. The continent is far north to the equator line. Therefore, approximate shape of
the continent might be distorted if it uses WGS 1984 datum which sets the equator line as its latitude
of origin.
8- Create a new map and add the utmzone.shp data set from the mgisdata\World folder and the
spcszn83 feature class from the mgisdata\Usa\usdata geodatabase. Examine these locations
relative to the UTM and State Plane zone boundaries. Select which zone would be a better (less
distorted) choice for the area, and explain why.
(Amarillo, Texas / Pensacola, Florida / State of
Tennessee)
Three mentioned locations are situated in the following zone boundaries:
Zone Located
Place
UTM
State Plane Zone
Amarillo, Texas
14S zone
Texas North zone
Pensacola, Florida
16R zone
Florida North zone
State of Tennessee
16S and 17S zone
Tennessee zone
To determine which zone would be a better choice for the area would first start by answering
the characteristics of UTM and State Plane projection. State Plane projections are designed to best
measure a particular region (in this case USA) with minimum distortion within the particular region.
On the other hand, UTM projections are used to measure a small area within a single UTM zone.
However, if the area of interest goes beyond the boundary of a UTM zone, distortion might happen
when it is projected. Therefore, in this case State Plane zone would be a better choice f or the area.
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