Cartography, GPS, GIS
On Tuesday, Leo gave a presentation on cartography and GPS. He showed us that cartography is the art and science of knowing where you are and what is around you. Cartography basically means making maps. So, what is a map? A map is a drawing of the sky, the city, a route, or a depiction of the world. The earliest map was a cave painting. Maps are used in the military, wayfinding, and political and economic resources. Cadastial maps are used to show land ownership.
To make a map, you need to first, figure out where you are: At home, On Earth, On America, for example. You can use latitude and longitude to determine where you are. Latitude is the location relative to the equator (North or South). Longitude is the location relative to the Prime Meridian. The International Date Line is an imaginary line on the surface of the Earth opposite the Prime Meridian where the date changes as one travels east or west across it.
To find the latitude the old-fashioned way, you use a sextant. To find the longitude, you will need the prcise time in two places. There was once a Longitude Prize. This prize was for finding a practical way to find the longitude. In 1736, John Harrison created the first true marine chronometer, H1. In 1741, he made an imroved chronometer, H4.
Land surveyors use a tape measure, a level, a theodolite, and a position with known location and elevation. The Total Station GPS is a measuring tape, theodolite, and global positioning system all in one. Once you know the position of two or more points, plot the points to make a map. The Total Station GPS helps you to find the points and positions of your locations.
Map projections: ** ALL MAPS DISTORT DATA!!** so be careful when looking at maps.
GPS – Official Name: Navstar GPS
– Operational on April 27, 1995
– uses 24 & 32 satellites
The satellites have very precise atomic clocks and are all synchronized.
GIS is the Geographic Information System. It is a system of information and allows you to add information as well. The GIS can be visualized as a map and not a spreadsheet. You can find certain areas when they are needed. The GIS helps answer questions and solve problems by looking at your data easily and can share it. One example of its helpfulness is mapping potential earthquakes.
I feel that we have learned alot about Cartography, GPS, and GIS this week.