Digital Mapping
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Week4lecture2finishcoordinatesystemsflatearthstartprojections-11.pptxExam in 2 weeks!
Pack Winners (Split)
Lucy Fletcher and Nic Rodriguez
Diamond Anderson from week #2
The pleasure of known quantities
Decimal Degrees vs. Degrees Minutes Seconds
Decimal Degrees – what we typically use what we create maps
Easier to store
Use + and – to indicate north/south and east/west
Other Formats – Easier to Read/Understand
360 Degrees in a circle
60 minutes in a degree
60 seconds in a minute
The Washington monument is located at 38° 30′ 30″ N, 77° 40′ 30″ W (degrees minutes second notation)
38 remains the same
30/60 = .5 – the 30 is the number of minutes and it’s out 60 (just like hours)
30/(60*60)3600 = .008333
38 .50 .008333
or 38.50833333, -77.675000 (decimal degrees notation).
77 Remains the same
40/60 = .6666
30/3600 = .008333
( .6666 + .008333
ADD THEM TOGETHER!
Positive and negative
Tuesday
Started Coordinate Systems
Reviewed FOSS vs. Proprietary Software
Google Maps vs Leaflet (A JS library who got created by someone who plays in a band)
Democratization of Mapping
Event Listeners in Web Maps vs. Static Maps
Q: What is the shape of Earth?
…
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A: “Earth-shaped”(a geoid)
What is the best way to represent the geoid?
That is the question that we will investigate today. In an ideal world, we could use globes for everything, but that is obviously impractical: physically and the question of “zooming in” and making large-scale maps. How do we take something that is round and make it flat?
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Why…
Coordinate Systems…
A map is of a real place – the earth
We have to model it (Ellipse)
How we model the earth changes the way we find locations and map things!
Outline
Coordinate System = Datum + a graticule
Datum
Attempts to model Earth’s surface mathematically
Based on an ellipsoid with minor modifications (based on location you are mapping)
We start with a datum, the foundation of all projection systems.
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Latitude, Longitude, and Graticules
Lines of latitude are also known as parallels
modernsurvivalblog.com
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Lines of longitude are also known as meridians
modernsurvivalblog.com
Graticule
Need origin
Question
Why is it important that we agree on where things are located on a map?
Gosh Darn!
Listen Here Buddy!
You just hold your horses!
Coordinate Systems and Projections manipulate spatial properties of earth
How large is a place?
How far is it from one place to another?
Borders/access to resources
Politics – splitting up/gaining access to constituency
Why not flat earth?
