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Professor: Chelsea Nestel...

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Geospatial Technology describes the use of a number of different high-tech systems and tools that can acquire, analyze, manage, store, or visualize various types of location-based data What are three major geospatial technologies? ● Geographic Information System (GIS)-most used ● Remote sensing (RS): ● Global Positioning System (GPS): ● GPS and RS collect data, GIS processes, analyzes and manages data Geographic Information System (GIS): a computerized system for analyzing and solving geographic problems Remote Sensing Acquisition of data and imagery from the use of satellites (satellite imagery) or aircraft (aerial photographs). Global Positioning System (GPS): Acquiring real-time location information from a series of satellites in Earth’s orbit. Google Earth 3D Globe The scientific process ● Observation ● Data ● Information ● Knowledge Geographic/Geospatial information

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elements of geographic information include location (x, y), Time, and Attribute. Time is an optional element but location is essential Geographic attributes are specific statistics tied to geographic location, e.g., Population density, Tax rates, Health data (lung cancer rate),Temperature, Air pressure Geographic Information vs. Spatial Information "Geographic" has to do with the Earth, its two-dimensional surface, its three-dimensional atmosphere, oceans and sub-surface

“Spatial” has to do with any multi-dimensional frame of reference How to represent geospatial information Through maps? Reference maps Thematic maps Navigational maps Persuasive maps Reference maps

depict locations; (Examples: Road maps, Google maps, Bing Map, mapquest.com, Openstreemap.org, USGS Topo maps) Thematic maps (Statistical Maps) depict spatially-referenced variables of interest (attributes); Weather, population density and geology maps are examples of thematic maps. Navigational maps depict paths and routes

two types of navigational maps Nautical charts: created specifically for water navigation Aeronautical charts: designed for the air navigation Persuasive maps present a graphical argument Geodetics "Geodesy" focuses on the measurement and representation of precise location and motion of the Earth Geomatics The scientific process of using geographic information (gathers, analyzes, interprets and distributes) Geographic Coordinate System unprojected coordinate system that uses is Measured in terms of Degree, Minutes, Seconds (lat & Lon)

Latitude - parallel to equator (0 degrees) - Range: 0-90 increase upwards from equator and downwards from equator (i.e.: North Pole = 90N and South Pole = 90S) - Unit: Degrees Longitude - Imaginary vertical lines - Range: 0o-180o - Length of a degree of longitude decreases from the equator to a pole Prime Meridian - 0 degrees longitude, Greenwich, England - East of the prime meridian, longitudes are given positive values up to 180 degrees - West of the prime meridian, longitudes are given negative values up to 180 degrees

Ellipsoid

Model of the Earth as a smooth surface with a larger radius (bulges) at the equator Datum

Reference system for plotting locations on a map using horizontal or vertical models ● ● Geoid

-Horizontal examples: measure a specific position on the Earth's surface using coordinate systems such as latitude and longitude (ex. NAD27, NAD83,WGS84) -Vertical examples: zero surface to which elevations or heights (ex. Mean Sea Level (MSL))

Accounts for variations in gravity across earth’s surface by using datums (mean seal level) Map Projection mathematical process of transforming a particular region of our earth's three-dimensional curved surface into a two-dimensional flat map. Map Distortion The process of transferring information from the Earth to a map causes every projection to distort at least one aspect of the real world – shape, area, distance, or direction.Every projection can only keep one or two of these accurate, or compromise between all four while preserving none of them Mercator projection Conformal Projection in 1569. Its strength was that it was useful for European maritime navigators, encouraged Northern Hemisphere as dominant McArthur's Corrective Map of the World drew South-up map to show Australlia was not bottom of the World Gall-Peters projection Famous Conformal Projection: Equal Area (Size preserved), True Direction; Shape (conformity) and Distance Not Preserved Tissot’s Indicatrix characterize distortions using circles due to map projection. Before being projected, circles are equal in area and shape on the globe, but show distortions afterwards. Projections by Surface - Cylindrical - Conical - Planer Cylindrical Projection based on projection of the globe onto a cylinder most accurate near the equator, but shapes and distances are distorted near the poles Conical Projection

- very good for Polar Regions - It is also good for aeronautical maps because it shows latitude in the form of a circle. - not good in general displaying large areas because greater distortion the further you move from the line where the cone intersects the globe (Standard parallel). And distortions differ depending on if you’re above or below the standard parallel. Standard Parallel

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Single parallel projection is tangential to the globe along one line of latitude, distortion increases north and south of lines ● Secant conic projections have two lines of contact and, therefore, two standard parallels. Two most common conic/conformal projections Albers Equal-area conic and Lambert conformal conic (LCC) Planar (azimuthal) Projections - projecting globe onto a plane - constructed distances and directions are correct but only from central point. 5 Projections by geometric distortion

1. Conformal: preserve shape (angles on the globe) Conic projection 2. Equivalent (equal area): preserve size or area 3. Equidistant: preserve distance 4. Azimuthal or Zenithal: preserve direction 5. Compromise: don't preserve area, shape, distance, or direction but minimize distortion of all of these, especially in polar region

Tangent & Secant Projection

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Tangent projections: Projection surface touch the globe surface along a line (a line of tangency) Secant projections: have two lines of contact or tangency between the projection surface and globe surface, therefore, two standard parallels. ● The lines where the cone, cylinder, or plane is tangent with the globe surface or secant are the places with the least distortion Aspects of Map Projection ●

Normal (equatorial): Projection surface is tangent or secant along the parallels or the lines of latitude. ● Transverse: tangent at a selected meridian or secant at two meridians (lines of longitude) ● Oblique: line of tangency for a projection does not run along a parallel nor a meridian Geographic Coordinate System projected coordinate system

which is a reference system used to locate x, y, and z positions of point, line, and area features in two or three dimensions. planar coordinate system Once map data are projected onto a planar (2 dimensional) surface, features are referenced using a two-dimensional measurement system that locates features on a plane based on their distance from an origin (0,0) along two perpendicular axes Cartesian Coordinate System two-dimensional, planar coordinate system in which horizontal distance is measured along an x-axis and vertical distance is measured along a y-axis, divided into four quadrants Universal Transverse Mercator (UTM) global 2-dimensional Cartesian coordinate system that gives locations on Earth's surface by dividing the earth into 60 zones. Each zone is 6 degrees longitude wide, and runs from 80°S and 84°N latitude -Each zone is drawn on a Transverse Mercator projection

UTM coordinate Formatting EXAMPLE: 305,900m E, 4,771,650m N, Zone 16 North Where first six-digital integer is x-coordinate in meters, Second seven-digital integer is northing y-coordinate in meters, and finally we have zone number (16) and hemisphere (northern) UTM eastings and northings Easting: is the east-west x-coordinate, which is the distance from the origin. Easting varies from near zero to near 1,000,000 m. False Easting: I n both the northern and southern hemispheres, an easting v alue (x coordinate) of 500,000 m is assigned to the center line of each zone to ensure no negative values (False northing same thing with y coordinate and 10 million value in southern hemisphere so no -#s) State Plane Coordinate System (SPC) Projection: Projections for each State chosen to minimize distortions Zone boundaries coincide with state and national borders Two false origins are established Predominantly east-west states (such as Texas) use secant case Lambert conformal conic projections. States of greater north-south extent use transverse Mercator projection States of greater north-south extent use transverse Map Scale expresses the relationship between distances on the map and their corresponding ground distances. three standard options for representing scale Representative fraction (RF), Verbal scale and Scale bar. Representative fraction (RF) ratio between map and ground distance(ex. 1:50,000)

Verbal Scale uses words to describe the ratio between the map's scale and the real world (ex. 1 inch to 2 miles) Scale Bar means it use a bar or line to divide into several segments to represent a scale. map scale calculation - Calculate ground distance based on map scale and map distance - convert verbal scale to RF

Small scale map is a map shows a large area with little detail. (1:25000) Large-sclae map large scale map shows a much small area but gives us more details. (1:100) NAVSTAR (Navigation System, Timing and Ranging) is a satellite based navigation system and can provide accurate positioning 24 hours a day, anywhere in the world, used by DOD Global Positioning System (GPS) A constellation of 24 satellites orbiting around Earth that deterrine position 3 Segments of GPS 1) Space Segment is a constellation of satellites for broadcasting signals, 2) Control segment is a set of ground station for monitoring, tracking and correcting those signals, 3) User Segment are all GPS receivers for receiving those signals How GPS finds a location? the technique called “trilateration” is used to determine GPS locating a position. At least 3 satellites required for 2D fix, which means locate a point on the earth surface. 4 satellites used to provide 3D fix to compensate for inaccurate clock in GPS receivers, which means that it can determine elevation of a point on the Earth surface. Trilateration the process that uses distance from at least three known locations to determine position D = time delay * speed of light 2D Trilateration At least 3 satellites required for 2D fix, which means locate a point on the earth surface. Often used when plotting a map 3D Trilateration 4 satellites used to provide 3D fix to compensate for inaccurate clock in GPS receivers, which means that it can determine elevation of a point on the Earth surface b/c it measures spherical distance rather than just linear distance

Selective availability intentionally degration of signal by DOD, shifted amount of error up to 100 m (eliminated in 2000) Multipath Error Disruption of the GPS signal due to obstructions like buildings and trees (greatest source of error in forestry settings and the most difficult to combat.) Differential GPS (DGPS) uses a series of base stations at locations on the ground to provide a correction for GPS position determination -can be in real time or post processing -error reduced to less than 5 meters Wide Area Augmentation System (WAAS) new satellite-based “real-time” DGPS correction method that collect and monitor the signals sent by GPS satellites. - can reduce error to 3 m Five Categories of GPS Application navigation, location, timing, mapping, and tracking. Real world GPS applications ●

precision farming

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open-pit mining oil exploration airport and harbor approaches animal migration and population studies vehicle tracking Construction - tunnels, golf courses, roads, etc. Emergency services - the closest ambulance or fire truck is sent to an emergency, thereby saving time. ● Atmospheric studies - ozone layer, air quality, etc. ● archaeological explorations ● Recreational activities - camping, boating, etc. ● astronomical telescope pointing ● Networking - speed is increased, the Internet is highly synchronized because of GPS. ● aiding the blind Navigation GPS system allows us to navigate on water, air, or land and get from one location to another efficiently Location GPS is the first system that can give accurate and precise measurements anytime, anywhere and under any weather conditions.(ex. measure movement of glaciers, growth of mountains) Timing carry an extremely precise atomic clock that contributes very precise time data to the GPS signals (ex. communication, finance networks) Mapping

GPS is used for creating maps by recording a series of locations. The best example is surveying. (widely used in various areas, such as archaeology, geology, etc.) Tracking ways of monitoring people and things such as packages, or moving vehicles. (ex. keep track of some criminals and paroles.) Aerial photographs Images taken from cameras mounted from aircrafts. Satellite imagery Images taken from cameras mounted from satellites Orthophotographs Images in which distortion from the camera angle and topography has been removed and corrected Image Interpretation The act of examining aerial photographs/images for the purpose of identifying objects and judging their significance. Photography Platform The advancements in imaging capability airplanes and satellites major platforms for taking images. Balloons and birds, specifically pigeons, used before airplanes were popular. Aerial Photographs based on Electromagenetic Spectrum Based on what portions of electromagnetic spectrum are captured by the cameras, aerial photographs can be black and white or color. Panchromatic Photos Black and white photos sensitive to UV and Visible light (capturing ER in the 300 to 700 nm), The greater the amount of visible light, the lighter its tone on the final photo is ● Healthy vegetation typically very light (nearly white ● Dead vegetation and roads appear black True Color Photos are capturing the three main bands of visible light—red, green, and blue—and the colors are composited together in digital imagery Color infrared (CIR) photo (false color image) captured with a special type of film sensitive to infrared light because Infrared energy is invisible to the naked eye. In order for us to see infrared energy reflection, a special filter is applied to the film and the end result is a CIR photo. typically used to help differentiate among vegetation types. CIR Color Appearance on Features ● ●

Intense bright red typically represent healthy vegetation,more chlorophyll (green grass, trees) Lighter tones of red, magenta, pinks generally represent dying vegetation,less chlorophyll

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White, blue, green, or tan: represent soils. Darker shades of soil generally indicate higher moisture levels or organic matter. Buildings and manmade materials such as concrete and dry gravel ● Dark blue to black - Water ranges from shades of blue to black depending on the clarity and depth. Principal Point geometric center of the photograph Nadir is the point vertically under the camera center when the photo was taken. Categories based on altitude and position of camera Depending on camera positions and angles towards to the ground while taking the photos, the aerial photographs could be vertical, tilted or oblique Vertical Photographs The principal point on the photo is the same as nadir point on the ground Low Oblique photographs Photographs are taken from 300' to 1,000' at a 5 to 30 degree angle through the open door of the helicopter. This is a good way to show the face of a building without showing too much roof. The most detailed images are low-altitude air photos. Typically, low-altitude air photos are taken by the balloons, or light aircraft, particular helicopters. High Oblique Photographs Photographs are taken from 8,000' to 13,000' at a 30 to 60 degree angle of airplane door. This is a good way to show areas from 2 to 20 square miles. ● Provides less environmental detail since the image scale is much smaller. ● Has advantage that more ground area can be covered on a single photo. Relief Displacement In aerial photos, tall objects (such as terrain, towers, buildings) have tendency to “bend” outward from the center point Typically, the higher the flying height, the less the relief displacement. Orthophotographs geometrically "corrected" (remove relief displacement); uniform scale Image interpretation is the process of extraction of qualitative and quantitative information from a photo or map, , by using human knowledge or experience. o Photo interpretation elements/clues](PASSSSTT) ● ● ● ● ● ●

Tone/hue -- lightness/darkness of an object, or color if it's a color or CIR photo Texture-coarse or fine, such as in a corn field (distinct rows) vs. wheat field (closely-grown plants) Shape- square, circular, irregular Size- small to large, especially compared to other known objects Shadow- objects like buildings and trees cast shadows that show vertical height and shape Pattern- many similar objects may be scattered on the landscape, such as oil wells

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Site- the characteristics of the location; for example, don't expect a wetland in a large city's downtown ● Association- an object's relation to other known objects -- for example, a building at a freeway off-ramp may be a gas station based on its relative location HINT: (PASSSSTT) Remote Sensing It is ‘obtaining information, about objects, without physical contact.’ ● First, they provide timely data and information ● Second, remote sensing allows us to sense energy in wavelengths that human eyes cannot see. ● Finally, remote sensing images are the best temporal snapshots of the ever changing world. Remote Sensing Process ● Energy Source or Illumination (A)-souce illuminates energy ● Radiation and the Atmosphere (B)-travels through atmosphere ● Interaction with the Target (C)-reaches target and interacts ● Recording of Energy by the Sensor (D)-sensor collects radiation/info ● Transmission, Reception, and Processing (E)-transfer data ● Interpretation and Analysis (F)-anayze ● Application (G)-release new info, help world Passive remote sensing detect or measure energy that comes from an external source such as sun. For all reflected energy, this can only take place during the time when the sun is illuminating the Earth. Active Remote Sensing provides its own energy source for illumination. The active sensor emits radiation which is directed toward the target to be investigated. The radiation reflected from that target is detected and measured by the sensor. (ex. radar) Electromagnetic (EM) Spectrum shows the range of all possible wavelengths of electromagnetic radiation. ranges from the shorter wavelengths (including gamma and x-rays) to the longer wavelengths (including microwaves and broadcast radio waves) Shortest to Longest Wavelengths ● Short: UV(practical for remote sensing), X-ray, Gamma ● Visible: 0.4~0.7 um (VBGYOR) "ROYGBV backwards" ● Infrared: .72-1000 ● Reflected (0.72-3), thermal (3-100), Near (.72-1.3), mid (1.3-3), far (7-1000) Ultraviolet or UV practical for remote sensing. Visible Spectrum light which our eyes - our "remote sensors" - can detect Remote sensing of vegetation and for the identification of different objects by their visible colors. Wavelength: (VBGYOR) "ROYGBV backwards"

Infared Radiation ● ●

divided into two categories based on radiation properties - the reflected IR, and the thermal IR. reflected IR region is used for remote sensing purposes in ways very similar to radiation in the visible portion. ● thermal IR region energy is essentially the radiation that is emitted from the Earth's surface in the form of heat. ● Infrared images obtained by sensors in satellites and a...