using arcGIS Question 5. ArcGIS records projection and coordinate system informa

Question

using arcGIS

Question 5. ArcGIS records projection and coordinate system information into a file with prj extension. Open MD_cities_SPCS.prj in any text editor (e.g., WordPad, Notepad, etc.). Read the prj file, and explain the following information for the MD_cities_SPCS layer: projection, geodesy, GCS, geodetic datum and unit. Make sure you do not change the file (i.e., do not save the changes if you ever modify the content of this file. You may read ArcGIS Help to answer this question. (2 points)

Explanation / Answer

According to ArcGIS record projection and coordinate system the following points are explained below:-

1. Projection:-
A projection is the means by which you display the coordinate system and your data on a flat surface, such as a piece of paper or a digital screen. Mathematical calculations are used to convert the coordinate system used on the curved surface of earth to one for a flat surface. Since there is no perfect way to transpose a curved surface to a flat surface without some distortion, many different map projections exist that provide different properties. Some preserve shape, while some preserve distance. Others preserve area or direction. The extent, location, and property you want to preserve must inform your choice of map projection. There are over 4000 coordinate systems in the ArcGIS platform, so it is likely that you can find one to match your data. In the event that you cannot, you can create a custom coordinate system to display the data.

2.Geodesy:-
Geodesy is the science of accurately measuring and understanding three fundamental properties of the Earth: its geometric shape, its orientation in space, and its gravity field— as well as the changes of these properties with time. By using GPS, geodesists can monitor the movement of a site 24 hours a day, seven days a week.

3.GCS:-
A geographic coordinate system is a method for describing the position of a geographic location on the earth's surface using spherical measures of latitude and longitude. These are measures of the angles (in degrees) from the center of the earth to a point on the earth's surface when the earth is modeled as a sphere. When using a spheroid (ellipsoid), latitude is measured extending a line perpendicular to the earth's surface to the equatorial plane. Except at the equator or a pole, this line will not intersect the center of the earth.The geographic coordinate system consists of latitude and longitude lines. Each line of longitude runs north–south and measures the number of degrees east or west of the prime meridian. Values range from -180 to +180°. Lines of latitude run east–west and measure the number of degrees north or south of the equator. Values range from +90° at the North Pole to -90° at the South Pole.

4.geodetic datum and unit:-
Geodetic datums define the size and shape of the earth and the origin and orientation of the coordinate systems used to map the earth. Hundreds of different datums have been used to frame position descriptions since the first estimates of the earth's size were made by Aristotle. Datums have evolved from those describing a spherical earth to ellipsoidal models derived from years of satellite measurements.
Modern geodetic datums range from flat-earth models used for plane surveying to complex models used for international applications which completely describe the size, shape, orientation, gravity field, and angular velocity of the earth. While cartography, surveying, navigation, and astronomy all make use of geodetic datums, the science of geodesy is the central discipline for the topic.
Referencing geodetic coordinates to the wrong datum can result in position errors of hundreds of meters. Different nations and agencies use different datums as the basis for coordinate systems used to identify positions in geographic information systems, precise positioning systems, and navigation systems. The diversity of datums in use today and the technological advancements that have made possible global positioning measurements with sub-meter accuracies requires careful datum selection and careful conversion between coordinates in different datums.

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.