A projected coordinate system is always based on a geographic coordinate system that is based on a sphere or spheroid. In a projected coordinate system, locations are
identified by x,y coordinates on a grid
, with the origin at the center of the grid.
What is the projected coordinate system?
A projected coordinate system is
a flat, two-dimensional representation of the Earth
. It is based on a sphere or spheroid geographic coordinate system, but it uses linear units of measure for coordinates, so that calculations of distance and area are easily done in terms of those same units.
How do you choose a projected coordinate system?
Your choice of a projected coordinate system depends on many factors, including the part of the world you are mapping, the scale of your map, and the purpose of your map. You want to choose a projected coordinate system in
which the places and properties that are most
important to your map are the least distorted.
What is an example of a projected coordinate system?
Examples are:
South central Texas
in the United States uses “NAD83( NSRS2007) / Texas South Central (ftUS)” with unique EPSG code 3674. Belgium uses “ETRS89 / Lambert 2008” with unique EPSG code 3812.
How do you determine projection?
For any given projector, the width of the image (W) relative to the throw distance (D) is know as the
throw ratio D/W or distance over width
. So for example, the most common projector throw ratio is 2.0. This means that for each foot of image width, the projector needs to be 2 feet away or D/W = 2/1 = 2.0.
Why would you use a projected coordinate system?
The following are some reasons for using a projected coordinate system:
You want to make accurate measurements from your map and be sure that the spatial analysis options you use in ArcMap calculate distance correctly
.
What is the difference between a projection and a coordinate system?
Unlike a geographic coordinate system, a projected coordinate system has
constant lengths, angles, and areas
across the two dimensions. A projected coordinate system is always based on a geographic coordinate system that is based on a sphere or spheroid.
How do projected coordinate systems work?
A projected coordinate system is a flat, two-dimensional representation of the Earth. It is based on a sphere or spheroid geographic coordinate system, but it uses
linear units of measure for coordinates
, so that calculations of distance and area are easily done in terms of those same units.
What is the difference between map and coordinates?
Technically, there are two classes of coordinate reference systems:
geographic and projected coordinate systems
. Geographic coordinate systems are three-dimensional grids, while projected systems use map projections to view the world in 2D.
What is the common coordinate systems?
A geographic coordinate system uses longitude and latitude expressed in decimal degrees. For example,
WGS 1984 and NAD 1983
are the most common datums today. Before 1983, NAD27 was the most common datum.
What are the two types of coordinates?
Data is defined in both
horizontal and vertical coordinate systems
. Horizontal coordinate systems locate data across the surface of the earth, and vertical coordinate systems locate the relative height or depth of data.
What is on the fly projection?
On-the-fly projection means that
individual objects (coverages, grids, images etc) can define their own projection
. If they do, they will be reprojected to a common display projection when drawn.
What are the component of projected coordinate system?
Projection formulas are mathematical expressions that convert data from a geographical location (
latitude and longitude
) on a sphere or spheroid to a corresponding location (x and y) on a flat, two dimensional surface. The PCS uses two axes: the x-axis, representing east-west, and the y-axis, representing north-south.
Is UTM a projected coordinate system?
The Universal Transverse Mercator (UTM) system is a
commonly used projected coordinate reference system
. UTM subdivides the globe into zones, numbered 0-60 (equivalent to longitude) and regions (north and south).
What are the different types of projection?
- Conic (tangent) A cone is placed over a globe. …
- Conic (secant) A cone is placed over a globe but cuts through the surface. …
- Cylindrical aspects. A cylinder is placed over a globe. …
- Planar aspects. …
- Polar aspect (different perspectives)
