Introduction to gis


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  • Geographic information systems (GIS) allow us to conduct spatial analysis faster, better, and cheaper now than in Dr. Snow’s day. He only had to compare two competing theories. What if he wanted to analyze all aspects of the victims’ lives. How close did they live to various factories? Where did they get their meats, fruits and vegetables, or breads? Where did they go to school, work, or church? What were their mattresses made of? How many people lived in their homes? What kind of wood did they burn for fires? What kind of oil did they use in their lamps? What materials were their clothes made out of? The list of possible questions is endless. Answering all those questions and determining if they were at all related to the cholera outbreak in a timely manner would have been an impossible task for Dr. Snow. With GIS we can.
  • There are two ways that the layers can be visualized on a map; as a vector or raster layer Raster layers are organized in a grid of identically sized cells. The top image is an example of a raster layer. The cells have a uniform length and width (square shaped) and are called “pixels.” Each cell has its own individual attribute data. Satellite images and aerial photos are types of raster layers where each cell displays what light wavelength is emitted or reflected from that location. The cells in a pure black and white photo represent whether light does emit or reflect from a cell’s location (white) or does not emit or reflect from the location (black). Examples of raster layers include temperature, elevation, and satellite imagery. Vector layers are represented as points, lines, or polygons. A vector layer cannot mix types together. One layer cannot have both points and polygons. The layer would have to be split into two separate layers; one for points and one for polygons. The bottom image is an example of at least three separate vector layers forming one image. Vector data is used when the features have specific locations and boundaries and the attribute data is uniform throughout the individual features. Examples of vector layers include bus stops (point), roads (line), and counties (polygon).
  • This slide shows five distinct, but related, data layers. The Capital layers is an example of a point vector layer. The Roads and Rivers layers are examples of line vector layers. The Lakes and States layers are examples of polygon vector layers.
  • When the five data layers from the previous slide are loaded into a digital map they combine into this one image. Each layer is still separate and can be turned on and off individually. The legend on the left side of the image shows the order of the images. The States layer is at the bottom of the image while the US Capitals layer is at the top. The layer order determines how the map draws the image with the top layers being drawn on top of the layers below it. If the States layer was moved to the top of the order it would cover the other layers and nothing else would be visible (except for the Great Lakes features of the Lakes layer) because it is being drawn on top of the other layers.
  • Introduction to gis

    1. 1. Introduction to GIS Muhammad Haris Lecturer GIS Center PUCIT 1
    2. 2. Topics: • GIS for a Beginner • GIS Around Us • Major Application Areas • Maps & GIS Softwares Muhammad Haris 2 Lecturer GIS Center PUCIT
    3. 3. Agenda: • GIS for a Beginner • GIS around us • Major Application areas • Maps & GIS Softwares Muhammad Haris 3 Lecturer GIS Center PUCIT
    4. 4. What is Geography• Geo – Earth• Graphy – Measurement• Geography hence is measurements and calculation related to Earth• Geography is divided into two main branches: – Human geography – Physical geography Muhammad Haris 4 Lecturer GIS Center PUCIT
    5. 5. Physical geography Muhammad Haris 5 Lecturer GIS Center PUCIT
    6. 6. Human geography Muhammad Haris 6 Lecturer GIS Center PUCIT
    7. 7. Geography in Final WordsGeography is the science that studies the lands, features, inhabitants, and phenomena of Earth Or Simply Geography is the study of any thing related to Earth Muhammad Haris 7 Lecturer GIS Center PUCIT
    8. 8. Informally 1st Definition of GIS (Beginner Level) GIS (Geographical Information System) = G+IS (Geography) + (Information System) Geography is the science that studies the lands, features, inhabitants, and phenomena of Earth Information System – A way of managing and manipulating the information digitally (using computers and digital devices) Muhammad Haris 8 Lecturer GIS Center PUCIT
    9. 9. People normally don’trealize that howimportant GeographicInformation is. Muhammad Haris 9 Lecturer GIS Center PUCIT
    10. 10. Estimates are that 80% of all data has a spatial component• Cellular Phone location• ID cards• Telephone Directories• Registration• Your favorite restaurant, park , shopping mall address. Muhammad Haris 10 Lecturer GIS Center PUCIT
    11. 11. GIS stands for Geographical Information SystemThe “bookish” definition:GIS is a system for capturing, storing, analyzing, managingdata that is associated to the earth w.r.t location Muhammad Haris 11 Lecturer GIS Center PUCIT
    12. 12. Very Important !!Very ImportantSpatial = Geographical = Locational Muhammad Haris 12 Lecturer GIS Center PUCIT
    13. 13. 2nd Definition of GIS (Intermediate Level) GIS = Spatial + AttributeA GIS links locational/spatial and attribute(non-locational) information and enables a person tovisualize patterns, relationships, and trendseasily and efficientlyHelps identify patterns not easily visible onpaper map. Muhammad Haris 13 Lecturer GIS Center PUCIT
    14. 14. GIS – Finding Patterns To explore highway accidents, wemight first make a map of whereeach accident occurred.We might use one color to locatethose accidents that occur at night anda second color for those that occurduring the day, and then we mightsee a more complex pattern. Muhammad Haris 14 Lecturer GIS Center PUCIT
    15. 15. A Muhammad Haris 15 Lecturer GIS Center PUCIT
    16. 16. But how exactly GIS works? Muhammad Haris 16 Lecturer GIS Center PUCIT
    17. 17. 3rd Definition of GIS (Advance Level)GIS = Overlaid layers Muhammad Haris 17 Lecturer GIS Center PUCIT
    18. 18. Example Muhammad Haris 18 Lecturer GIS Center PUCIT
    19. 19. Spatial Data Formats Raster -- Grid • “Pixels” • Each Pixel has a value • Satellite images and aerial photos are in this format Vector -- Linear • Points, lines, and polygons • Each feature stores attributes Muhammad Haris 19 Lecturer GIS Center PUCIT
    20. 20. Representation of Lines Raster VectorMuhammad Haris 20 Lecturer GIS Center PUCIT
    21. 21. VECTOR• Advantages: – Accurate calculations – Better visualization due to more detail – Compact data structure => small storage requirements• Disadvantages: – Complex data structures – Cannot handle remotely sensed data Muhammad Haris 21 Lecturer GIS Center PUCIT
    22. 22. RASTER• Advantages: – Simple data structures – Can display and manipulate remotely sensed data• Disadvantages: – Inaccurate graphics and area calculations – Blocky appearance with loss of detail as we zoom into the data – Large storage requirements Muhammad Haris 22 Lecturer GIS Center PUCIT
    23. 23. Example Muhammad Haris 23 Lecturer GIS Center PUCIT
    24. 24. 5 Data LayersRivers Layer Lakes Layer Capitals Layer Roads Layer States Layer Muhammad Haris 24 Lecturer GIS Center PUCIT
    25. 25. Muhammad Haris 25 Lecturer GIS Center PUCIT
    26. 26. The GIS process Muhammad Haris 26 Lecturer GIS Center PUCIT
    27. 27. The GIS processCapture Store Visualize AnalyzeGet Result Muhammad Haris 27 Lecturer GIS Center PUCIT
    28. 28. Agenda: • GIS for a Beginner • GIS Around Us • Major Application areas • Maps & GIS Softwares Muhammad Haris 28 Lecturer GIS Center PUCIT
    29. 29. Google Maps Muhammad Haris 29 Lecturer GIS Center PUCIT
    30. 30. Google Earth Muhammad Haris 30 Lecturer GIS Center PUCIT
    31. 31. Map MakerMuhammad Haris 31 Lecturer GIS Center PUCIT
    32. 32. Google Maps Street View Muhammad Haris 32 Lecturer GIS Center PUCIT
    33. 33. WikiMapiaMuhammad Haris 33 Lecturer GIS Center PUCIT
    34. 34. Agenda: • GIS for a Beginner • GIS around us • Major Application areas • Maps & GIS Softwares Muhammad Haris 34 Lecturer GIS Center PUCIT
    35. 35. Animal TrackingTracking endangered animals using radio transmitters Muhammad Haris 35 Lecturer GIS Center PUCIT
    36. 36. 3D Modeling for Urban Planning Muhammad Haris 36 Lecturer GIS Center PUCIT
    37. 37. Determining Location for Service Areas Example: Gourmet Bakery Muhammad Haris 37 Lecturer GIS Center PUCIT
    38. 38. Property Locator Internet Application Muhammad Haris 38 Lecturer GIS Center PUCIT
    39. 39. Centure 21 (, Renting, Purchasing houses Muhammad Haris 39 Lecturer GIS Center PUCIT
    40. 40. Emergency Routing Find Nearest HospitalFind Shortest path to it Muhammad Haris 40 Lecturer GIS Center PUCIT
    41. 41. US Flights Around the World Muhammad Haris 41 Lecturer GIS Center PUCIT
    42. 42. Agenda: • GIS for a Beginner • GIS around us • Major Application areas • Maps & GIS Softwares Muhammad Haris 42 Lecturer GIS Center PUCIT
    43. 43. Plot Level Map of DHA Muhammad Haris 43 Lecturer GIS Center PUCIT
    44. 44. General Overview Map of DHA Muhammad Haris 44 Lecturer GIS Center PUCIT
    45. 45. Satellite Map/Image of DHA (from Google Earth) Muhammad Haris 45 Lecturer GIS Center PUCIT
    46. 46. Lets Revise– GIS is G + IS– GIS is Attribute + Spatial– GIS is Layers– GIS is about finding patterns, static maps won’t easily– Spatial Data Formats (Raster , Vector)– GIS Applications areas (3D Models, Emergency routing, etc. )– GIS around us – Goolge Earth & Maps, Wikimapia Muhammad Haris 46 Lecturer GIS Center PUCIT
    47. 47. Assignment2 GIS Applications Muhammad Haris 47 Lecturer GIS Center PUCIT
    48. 48. Where GIS is being used Muhammad Haris 48 Lecturer GIS Center PUCIT
    49. 49. Raster Data’s Resolution 1. Spatial resolution 2. Spectral resolution 3. Radiometric resolution Muhammad Haris 49 Lecturer GIS Center PUCIT
    50. 50. Spatial ResolutionThe term resolution is the pixel count in digital imaging Higher the number of pixels, higher is the spatial resolution.• Spatial Resolution is the size of areas represented by each pixel in a digital photo• Google Earth Images has a spatial resolution of 1 meter per pixel Muhammad Haris 50 Lecturer GIS Center PUCIT
    51. 51. Spectral ResolutionIt is the range of wavelengths that an imaging system (satellite)can detect Higher the wavelength range, higher is the spectral resolution . Spectral resolution can also be defined as the number of frequency bands recorded. Higher the number of Bands Higher the spectral resolution Muhammad Haris 51 Lecturer GIS Center PUCIT
    52. 52. Radiometric ResolutionRadiometric resolution determines how finely asystem can represent intensity, and is usuallyexpressed as a number of levels or number ofbits.Important:For example a Raster Data that use 16 bits to storeintensity for a single pixel has more level of intensity thana raster data that uses 8 bits Muhammad Haris 52 Lecturer GIS Center PUCIT
    53. 53. GIS Softwares Muhammad Haris 53 Lecturer GIS Center PUCIT
    54. 54. GIS Softwares• MapGuide, GeoTools, uDig, MapServer• ESRI leads in the GIS field • Pioneers in GIS, • The 5 Largest Privately Held Software Company in the World • Extensive range of GIS software and Research material • Their flagship product ArcGIS leads in the GIS software domain Muhammad Haris 54 Lecturer GIS Center PUCIT