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Intro to GIS and Remote Sensing

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Intro to GIS and Remote Sensing

  1. 1. Introducing GIS and Remote Sensing Introduction to Mapping and GIS
  2. 2. Rowan University Think about all the activity occurring though out a landscape. How can we map, manage and analyze all that is going on? GIS!
  3. 3. US Census Data in Excel Think about keeping information about phenomenon on a landscape. How could you do it?
  4. 4. US Census Data in GIS GIS organizes that data with a map. But GIS is much more….
  5. 5. Data Types Aspatial data—data not tied to a location on the earth ’s surface Spatial data —data associated with a location on earth Much of the information we deal with daily has some spatial component.
  6. 6. What is GIS? <ul><li>Data Management </li></ul><ul><ul><li>Manages various kinds of GIS data including vector, raster, images, tables, other data files </li></ul></ul><ul><ul><li>Data models and architectures </li></ul></ul><ul><ul><li>Conversion between formats </li></ul></ul><ul><ul><li>Import/export utilities </li></ul></ul><ul><ul><li>Interacts with RDBMS (SQL Server, Oracle, etc…) </li></ul></ul>
  7. 7. What is GIS? <ul><li>Analysis </li></ul><ul><ul><li>Spatially aware data </li></ul></ul><ul><ul><li>Attribute and spatial query </li></ul></ul><ul><ul><li>Proximity and Overlay </li></ul></ul><ul><ul><li>Advanced geoprocessing techniques </li></ul></ul><ul><ul><li>Decision support </li></ul></ul><ul><ul><li>Flexible, customization </li></ul></ul><ul><ul><ul><li>Programming, scripting (to perform analysis) </li></ul></ul></ul>
  8. 8. What is GIS? <ul><li>Visualization </li></ul><ul><ul><li>Maps! Maps! Maps! </li></ul></ul><ul><ul><ul><li>If a picture is worth a 1000 words… </li></ul></ul></ul><ul><ul><li>Professional cartographic tool </li></ul></ul><ul><ul><li>Charts, graphs, tables, etc… </li></ul></ul><ul><ul><li>Various coordinate systems </li></ul></ul><ul><ul><li>2D and 3D </li></ul></ul><ul><ul><li>Web, desktop, handheld, etc… </li></ul></ul>
  9. 9. What is GIS? <ul><li>Data Management – Database View </li></ul><ul><li>Analysis – Model View </li></ul><ul><li>Visualization – Map View </li></ul>
  10. 10. “ G” vs. “IS” <ul><li>GIS uses maps to spatially analyze and search for patterns in the data that would otherwise not be found. ( Content ) </li></ul><ul><li>GIS stores, manipulates, and displays data files and relationships in a information system using standard computing practices. ( IT ) </li></ul><ul><li>With advances in technology, GIS users must now deal with both aspects! </li></ul>
  11. 11. The “G” <ul><li>“ G” = Geographic </li></ul><ul><ul><li>Denotes the concept of spatial location on Earth ’s surface </li></ul></ul><ul><ul><li>Importance of relative location (not just where you are but where you are in relation to everything else) </li></ul></ul><ul><ul><li>Theories and techniques in Geography form the basis of GIS </li></ul></ul>
  12. 12. The “I” <ul><li>“ I” = Information </li></ul><ul><ul><li>Substance (knowledge) about location </li></ul></ul><ul><ul><li>Factual and interpretative </li></ul></ul><ul><ul><li>Tables + Maps + Analysis </li></ul></ul><ul><ul><li>Transformation of table information into spatial context for analysis </li></ul></ul><ul><ul><li>Technology and computer systems </li></ul></ul>
  13. 13. What About the “S” in GIS? <ul><li>Systems </li></ul><ul><li>Science </li></ul><ul><li>Studies </li></ul><ul><li>Services </li></ul>
  14. 14. Geospatial? <ul><li>Geographic + GIS = “Geospatial” </li></ul><ul><li>Move in recent years to better define the industry and to focus on data and procedures (business) over geographic principles (academic) </li></ul><ul><li>Geospatial includes all subcomponents of GIS embedded in other areas (remote sensing, GPS etc.) </li></ul>
  15. 15. Not Just Computer Cartography
  16. 16. Core of GIS = “Layers”
  17. 17. Importance of Layers in GIS <ul><li>Geographic data = Representation of reality </li></ul><ul><li>Reality is complex. </li></ul><ul><li>GIS utilizes a layer approach </li></ul><ul><li>Each layer only includes information about one type of phenomenon. </li></ul><ul><li>Data layers must be aligned with one another </li></ul>
  18. 18. Importance of Layers <ul><li>Proximity </li></ul><ul><ul><li>Finding what is near or within a distance from a certain location or feature </li></ul></ul><ul><ul><li>e.g., all houses within 100 yards of a stream </li></ul></ul><ul><li>Overlay </li></ul><ul><ul><li>Combining two layers to create new information </li></ul></ul><ul><ul><li>e.g., habitat based on veg, elevation, and temp </li></ul></ul>
  19. 19. Families of GIS Data <ul><li>Vector mode or coordinate based </li></ul><ul><ul><li>Three vector objects exist—points, lines, polygons; these are called “features.” </li></ul></ul><ul><ul><li>They are represented by X,Y coordinates </li></ul></ul><ul><ul><ul><li>sometimes Z (3D), sometimes M (linear reference) </li></ul></ul></ul><ul><ul><li>Information about features is (are) called “attributes.” </li></ul></ul><ul><ul><li>Two types of vector models—topological and object </li></ul></ul><ul><ul><li>Topological means the data models stores relationships between vectors </li></ul></ul><ul><ul><li>Vector objects exist independent of any other nearby features </li></ul></ul>
  20. 20. Families of GIS Data <ul><li>Raster mode or grid cell </li></ul><ul><ul><li>Entire study area is covered by a grid </li></ul></ul><ul><ul><li>Each cell within grid is given a value </li></ul></ul><ul><ul><li>Values can be integer or decimal </li></ul></ul><ul><ul><li>Data can be discrete or continuous </li></ul></ul><ul><ul><li>Cell size is variable and linked to the file size of the raster data </li></ul></ul><ul><ul><li>Areas outside of the grid are ignored </li></ul></ul><ul><ul><li>Grid must be expanded if those areas are to be included </li></ul></ul>
  21. 21. Modeling Geospatial Reality Real World Vector Model Raster Model
  22. 22. Coding Vector GIS Reality Vector Mode Model of Reality
  23. 23. Coding Vector GIS Reality Vector Mode Model of Reality Polygon I Polygon II Polygon III Polygon V Polygon IV node A node B node C node E node F node G node D
  24. 24. Coding Raster GIS Data Reality Raster Mode Model of Reality
  25. 25. Coding Raster GIS Data 1 1 1 1 2 3 4 4 1 1 1 2 2 3 4 4 1 2 2 2 3 3 4 4 2 2 2 3 3 4 4 4 3 3 3 3 5 5 5 5 1 1 1 1 6 5 5 5 1 1 1 1 1 5 5 5 1 1 1 1 1 1 5 5 Reality Raster Mode Model of Reality
  26. 26. Advantages of Vector <ul><li>Vector data make maps that look more like maps we are use to seeing on paper. </li></ul><ul><li>The shapes of features are accurately represented. </li></ul><ul><li>Vector data can have topology </li></ul><ul><li>Vector data is good for managing attributes </li></ul><ul><li>Vector data has smaller storage requirement </li></ul><ul><ul><li>Only the objects need to be represented in the database (empty space in-between is not captured) </li></ul></ul>
  27. 27. Disadvantages of Vector <ul><li>Complicated data structure </li></ul><ul><li>Software must manage many data tables </li></ul><ul><li>Not good at representing geographic features that gradually change over location </li></ul><ul><ul><li>For example elevation or moisture in soil </li></ul></ul><ul><li>Slower processing time </li></ul>
  28. 28. Advantages of Raster <ul><li>Good at depicting continuously changing surfaces such as elevation or soil moisture </li></ul><ul><li>Grid format is simple data structure </li></ul><ul><li>Easier for computer to make analytical calculations </li></ul><ul><li>Ideal for utilizing remote sensing images </li></ul>
  29. 29. Disadvantages of Raster <ul><li>Maps can be blocky looking (depending on the size of the grid cells) </li></ul><ul><li>Cells can only be coded for one attribute when there may be more than one attribute at each location </li></ul><ul><li>Can have very large datasets (depending on the size of the grid cell) </li></ul><ul><li>Not topological: adjacency data structure </li></ul>
  30. 30. Remote Sensing <ul><li>Remotely-Sensed data is one of the most important sources of data for GIS. </li></ul><ul><li>RS means - Acquiring data from a distance </li></ul><ul><li>Usually uses electromagnetic energy </li></ul><ul><ul><li>sunlight, radar, laser </li></ul></ul><ul><li>Originally captured on photographic film </li></ul><ul><li>Recent platforms utilize digital sensors </li></ul>
  31. 31. Early Remote Sensing Platforms
  32. 32. What kinds of devices collect the data? <ul><li>Aircraft </li></ul><ul><ul><li>High altitude </li></ul></ul><ul><ul><li>Low altitude </li></ul></ul><ul><li>Spacecraft: </li></ul><ul><ul><li>Landsat </li></ul></ul><ul><ul><li>SPOT </li></ul></ul><ul><ul><li>Weather satellites </li></ul></ul><ul><ul><li>GeoEye-1 </li></ul></ul>Geosynchronous Orbit when the satellite moves at the same speed as the spinning earth – results in the camera staying over the same spot of the earth
  33. 33. Aircraft Images
  34. 34. <ul><li>Black and White or </li></ul><ul><li>“ Panchromatic” </li></ul><ul><li>Sensitive to visible light </li></ul>
  35. 35. Digital Orthographic Photos <ul><li>Digital photos of the earth </li></ul><ul><li>Usually acquired by aircraft </li></ul><ul><li>Orthographic means that the photo has all distortion removed </li></ul><ul><ul><li>A regular photo from an airplane will have distortion due to: </li></ul></ul><ul><ul><ul><li>Parallax – effect that distance away from the center point of a photo will always have distortion </li></ul></ul></ul><ul><ul><ul><li>Terrain – the hills and valleys or a land area will cause distortion in the photo </li></ul></ul></ul><ul><ul><li>An orthographic photo is adjusted by computer software to make the image line up with a flat map </li></ul></ul>
  36. 36. Digital Orthographic Photo - Infrared - 1995 You are here
  37. 37. Why Infrared? Artificial Turf
  38. 38. Remote Sensing Mediums <ul><li>Black and White or “Panchromatic” </li></ul><ul><ul><li>Sensitive to visible light </li></ul></ul><ul><li>True Color </li></ul><ul><ul><li>Similar to color film </li></ul></ul><ul><li>Infrared </li></ul><ul><ul><li>Sensitive to infrared frequencies that can ’t be seen by humans </li></ul></ul><ul><ul><li>Developed by military for identifying tanks painted with camouflage </li></ul></ul><ul><ul><li>Good for evaluating conditions of vegetation </li></ul></ul><ul><ul><li>Good for evaluating moisture in soil </li></ul></ul><ul><li>False-color adjusted </li></ul><ul><ul><li>When frequencies of received data are shifted to allow or enhanced human viewing </li></ul></ul><ul><li>Multi spectral </li></ul><ul><ul><li>When more than a single “band” of energy is captured </li></ul></ul><ul><ul><li>Color is multi-spectral (3 bands) </li></ul></ul><ul><ul><li>Some satellites can have 7 or even more “bands” of sensitivity </li></ul></ul>
  39. 39. The Electromagnetic Spectrum
  40. 40. The Visible Spectrum <ul><li>The visible spectrum is only a tiny window </li></ul><ul><li>We are blind to 99.99% of the energy in the universe </li></ul><ul><li>We have created devices that allow us to see beyond the range of human vision </li></ul>
  41. 41. Satellite Images <ul><ul><li>Weather satellite image: Winter in North America. </li></ul></ul>
  42. 42. What are the spatial units for which data are collected? <ul><li>Pixel or Picture Element </li></ul><ul><ul><li>Smallest unit of data collection </li></ul></ul><ul><ul><li>Features smaller than the pixel size can ’t be distinguished </li></ul></ul><ul><li>Pixel Sizes </li></ul><ul><ul><li>Landsat MSS = 79 meters </li></ul></ul><ul><ul><li>Landsat TM = 30 meters </li></ul></ul><ul><ul><li>SPOT = 10 meters </li></ul></ul><ul><ul><li>IKONOS = 1 meter </li></ul></ul><ul><ul><li>GeoEye-1 = 0.41 meters </li></ul></ul>
  43. 43. Spatial resolution keeps getting better... GeoEye-1
  44. 44. 1, 3, and 10 meters Spatial resolution keeps getting better...
  45. 45. Temporal Resolution <ul><li>Remote sensing images begin to get old as soon as they are taken. </li></ul><ul><li>Satellites repeatedly circle the earth. </li></ul><ul><li>Airplanes must be commissioned every time they photograph (expensive). </li></ul><ul><li>NJ aerial photography was taken 1995, 2002, and 2007. Statewide aerials often have to be taken in multiple years. (95/97) (07/08) </li></ul><ul><li>Turnaround is improving: NearMap’s 2cm imagery of Brisbane floods released within 1 week. </li></ul>
  46. 46. What is GIS? <ul><li>Now that we ’ve learned the essential elements that make up a GIS… </li></ul><ul><li>… and have seen examples of how GIS is being used… </li></ul><ul><li>… let ’s take a look at the big picture. </li></ul>
  47. 47. GIS Is Evolving Projects Systems Networks Integrated Coordinated Cooperative Moving to the Internet and Web Services
  48. 48. How is GIS used? <ul><li>Sometimes, the best way to learn about GIS is to see how it ’s being used….. </li></ul><ul><ul><li>Science </li></ul></ul><ul><ul><li>Emergency management </li></ul></ul><ul><ul><li>Government record-keeping </li></ul></ul><ul><ul><li>Business location </li></ul></ul><ul><ul><li>Environmental management </li></ul></ul><ul><ul><li>Planning </li></ul></ul><ul><ul><li>Crime mapping </li></ul></ul>
  49. 49. Creating a Digital Earth . . . A Nervous System for Spaceship Earth Measuring and Integrating Spatial and Thematic Information
  50. 50. Violence in Darfur <ul><li>Image shows 2004 & 2006. </li></ul><ul><li>Area too large and dangerous for small peacekeeping force. </li></ul><ul><li>Violence tracked using satellite images. </li></ul><ul><li>Article. </li></ul>
  51. 51. California Wildfires <ul><li>LA Times and local residents are mapping the spread of major wildfires. </li></ul><ul><li>Using web-based GIS to present and catalog data. </li></ul><ul><li>Article. </li></ul>
  52. 52. GeoCommons <ul><li>GeoCommons is a &quot;mashup&quot; maker </li></ul><ul><li>Upload your data – excel or GIS and have it mapped </li></ul><ul><li>Find data others have shared </li></ul><ul><li>Make maps, then export to Google Earth </li></ul>
  53. 53. Response to Haitian Earthquake <ul><li>Users of OpenStreetMap volunteered time to update the map around Port-au-Prince . </li></ul><ul><li>CrisisCamp volunteers are adding features such as camps, collapsed buildings & recovery efforts. </li></ul><ul><li>How volunteers are using GIS to help in Haiti. </li></ul>

Hinweis der Redaktion

  • Satellite images are recording more than just the &amp;quot;look&amp;quot; of the clouds.