Projections and coordinate systems
Download
1 / 17

Projections and Coordinate Systems - PowerPoint PPT Presentation


  • 139 Views
  • Updated On :

Projections and Coordinate Systems. Prepared by:. John McGee Jennifer McKee. With support from:. Acknowledgements: Barron Orr, AZ Geospatial Extension Specialist Operation On-Target. NSF DUE-0903270. in partnership with:.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Projections and Coordinate Systems' - ace


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Projections and coordinate systems l.jpg

Projections and Coordinate Systems

Prepared by:

John McGee

Jennifer McKee

With support from:

Acknowledgements: Barron Orr, AZ Geospatial Extension Specialist

Operation On-Target

NSF DUE-0903270

in partnership with:

Geospatial Technician Education Through Virginia’s Community Colleges (GTEVCC)


Projections and coordinate systems2 l.jpg
Projections and Coordinate Systems

Why do we need to worry about projections?

Your “layers” need to “match up” so that they will stack up in the right place (relative to each other)


Projections and coordinate systems3 l.jpg
Projections and Coordinate Systems

Different organizations use different coordinate systems and projections

If you can understand this (a bit) you will eliminate headaches later on…


Projections spheroids datums and coordinate systems l.jpg
Projections, Spheroids, Datums and Coordinate Systems

We are trying to represent a 3-dimensional, roundish, lumpy earth on a flat map

We can’t do this unless we project this roundish object onto a flat surface


Slide5 l.jpg

A Round Planet on a Flat Map?

?

Think of peeling an orange and then trying to lay the skin flat on a table – pretty difficult to do!


Slide6 l.jpg

Projection:

Transforming a 3-D planet

onto a flat surface


Map projections l.jpg
Map Projections

  • Geographic coordinates

    • latitude, longitude

    • degrees, minutes, seconds

    • spherical, not projected coordinates

  • Map projection

    • Process of transforming spatial relationships on earth’s surface (a sphere) onto a flat map




Most commonly used projections in va l.jpg
Most Commonly Used Projections In VA

Universal Transverse Mercator Projection (UTM): Used by The “Feds”

State Plane Coordinate System Projection (SPC): Used by Local Governments


State plane coordinate system spc l.jpg
State Plane Coordinate System (SPC)

They are most commonly used by local govts. because they represent small areas well.

State-Plane Coordinate systems are different in each state.


Slide12 l.jpg

Virginia State Plane Coordinate Zone Boundaries (SPCZ)

VA State Plane North Zone

VA State Plane South Zone




Most commonly used projections in va15 l.jpg
Most Commonly Used Projections In VA

Virginia also has another customized projection that was developed by VDOT called the Virginia-Lambert Conformal Conic projection.

It is now used by almost all state agencies because it covers the entire state.


The virginia statewide lambert projection is a custom projection developed by vdot l.jpg
The Virginia Statewide Lambert Projection is a custom projection developed by VDOT.

No “zones” (statewide coverage)

Here are the parameters for the VA Lambert (NAD83) projection

You won’t need this info. now, but keep it handy:


Why do you need to know this l.jpg
Why do you need to know this? projection developed by VDOT.

The layers need to “fall on top of each other”

Some of you will “get stuck” because one layer will not “fall on top of another layer” (because they may be in different coordinate systems / projections.


ad