Notes (08/18) - continuation of 8/13

Starting back up- Other Relatives of GIS (Geographic Information Systems)

  • Visualization (Google Earth)

    • Web-based, meant to visualize the environment

  • Remote Sensing (Data collected from far away - satellites - & can go in GIS)

Conveying Information on Maps

  • 3D landscape

    • Beyond the elevation contours of flat topographic maps (Contour/Isoline)

    • Digital Elevation Models (DEMs): Shaded-relief images resulting from database of precise elevations

      • Uses raster images (grid of cells)

      • Cells each have a number on it - Columns/Rows

      • Maps different features/elevations

  • Remote Sensing

    • Information collected from a distance through satellites, airplanes, drones, etc

    • Can include info beyond visible light

      • Infrared light

      • Good for measuring vegetation

    • Multispectral remote sensing detects & records many bands of the electromagnetic spectrum at once

    • Visible light & infrared sensing

      • Uses certains wavelengths from electromagnetic spectrum

      • “false-color” images created from sensors or film

        • Uses red to depict the infrared light

      • Blue - Green , Green - Red , Red - Infrared

    • Active remote sensing (uses own energy)

      • Radar: Radio detection & ranging

        1. Penerates clouds

        2. Works at night (not relying on sun so timing doesn’t matter)

        3. Maps terrain/elevation

      • Sonar: Sound navigation & ranging (permits underwater imaging)

      • Lidar: Uses reflected laser light to measure distances & 3D info

    • Passive remote sensing (energy bounces off - from sun to earth to satellite)

  • Video points

    • 120 satellites surround Earth gathers information and captures things that would otherwise be undetected by humans

    • Anything that radiates heat is seen through infrared radiation/light(?) & the satellites captures it

  • Long spectrum of the wavelengths of light

    • Humans have a limited view - can only see not even a quarter of all the colors that could exist

    • Infrared, Visible, Ultraviolet (UV), X-rays, Gamma rays

  • Blue, Green, Red, Near IF, Shortwave IF

Latitude & Longitude

  • How we mathematically determine our location on Earth

  • Latitude = North/South

  • Longitude = East/West

  • Prime Meridian

  • Measured in degrees, minutes, & seconds

    • Each degree divided into 60 min - Each min divided into 60 seconds

    • Digitally uses decimals for easier depiction

Earth-Sun relationships

  • Earth is at an angle, orbiting the sun

  • Rotation

    • Spin of earth on its axis

      • Spins towards East (counterclockwise)

    • 24hour day/night cycles

      • Over different longitudes as it spins

  • Revolution

    • Year-long movemnt arnd the sun

      • 1 year cycles

      • Different amt of sunlight at different latitudes over the course of the year

  • Circle of illumination

    • Day/night - Line between

  • Sun angle

    • Plane of the ecliptic

      • Imaginary flat area between sun & Earth

  • Earth is tilted 23.5 degrees from that plane

    • Causes seasonality

    • Angle that the sun is hitting any location

    • How long the day is in any location (longer days in summer & shorter days in winter)

Video points

  • Earth on imaginary line at which the earth spins & North-South poles connect

  • Spring Equinox - 21/22 of March (Northern Hemisphere) (Autumn in Southern)

  • Autumn Equinox - 22/23 of September (Northern Hemisphere) (Spring in Southern)

  • Summer Solstice - 21/22 of June (Northern Hemisphere) (Winter in Southern)

  • Winter Solstice - 21/22 of December (Northern Hemisphere) (Summer in Southern)