geographical concepts
Download
Skip this Video
Download Presentation
Geographical Concepts

Loading in 2 Seconds...

play fullscreen
1 / 11

Geographical Concepts - PowerPoint PPT Presentation


  • 199 Views
  • Uploaded on

Geographical Concepts. IDigBio Train the Trainers Georeferencing Workshop Gainesville, Fl 8-12, Oct 2012. Geographical Concepts. 3 main concepts Projection Datum Coordinate system. Geographical Concepts: Projections. Geographical Concepts : Projections. Bonne equal-area projection .

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 'Geographical Concepts' - shay


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
geographical concepts
Geographical Concepts

IDigBio Train the Trainers Georeferencing WorkshopGainesville, Fl8-12, Oct 2012

geographical concepts1
Geographical Concepts
  • 3 main concepts
    • Projection
    • Datum
    • Coordinate system
geographical concepts projections1
Geographical Concepts: Projections

Bonne equal-area projection

what projections do
What projections do

Rectangular projection

Tissot’sIndicatrix of distortion

projections examples
ProjectionsExamples

Geographic

preserves NS distance

Mercator

preserves shape (terrible for poles, distorts area)

slide8
Projections: Take Home Message
  • Projections compromises…
    • Equal-area
    • True shape
    • True scale
    • True direction
  • Select projection to fit your needs
geographical concepts datums
Geographical Concepts: Datums

Common Datums

NAD27 (North American Datum): system derived from land-based surveys, using Clarke 1886 ellipsoid

NAD83: satellite-based system using the Earth’s center as a reference point; eventually adopted as GRS80 (Geodetic Ref. System 1980)

WGS84 (World Geodetic System 1984): mathematically refined GRS80 used by the US military and default for GPS

For most uses, NAD83, GRS80, WGS84 are equivalent

ad