Cartography and Geographic Information Systems _GIS_

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					                                                       AGRO/MSYM/AGEN 431
                                                                                                  Cartography

                                                                                    Cartography has been described as
Cartography and Geographic                                                         the meeting place of Science and Art
 Information Systems (GIS)
                                                                            Science
                                                                                  The primary purpose of a map is to convey
                                                                                  information and geographic relationships
     Viacheslav I. Adamchuk
 Biological Systems Engineering Department                                  Art
                     Nebraska-
       University of Nebraska-Lincoln
                                                                                  Designing a map that contains useful
                                                                                  information in a readable format
           September 8, 2009




  Fundamental Cartographic Design                                                            Reference Systems

Clarity and legibility
Visual contrast                                                             Scale states the ratio of map
Selection of appropriate scale                                              dimensions to actual distances
Map components                                                                                                    0   5   10   20   30   40   50
                                                                                                                                                Miles
    Title
    Map itself
    Legend                                                                  Coordinate System is used to locate
    Scale
    North arrow
                                                                            objects
    Data source                                                                   Latitude / Longitude
    Authorship                                                                    Universal Transverse Mercator System(UTM)
                                                                                  State Plane Coordinate System (SPCS)




                         Map Scale                                            Geographic Information Systems
                                                                              “Hardware, software, data, organization, and
                                                                              institutional relations to automate, manage,
 Large Scale                                                                  analyze, and display georeferenced information of
   Earth is represented by a large area on the map                            and about the earth.”
   Generally show more detail                                                                               (National Research Council, 1997)

   Used to show local areas, neighborhoods, towns
                                         More detail




          Example: Small scale – 1:100
                                                                              “System of computer hardware, software, and
                    Large scale – 1:50                                        procedures designed to support the computing,
                                                                              storing, retrieving, analyzing and displaying of
 Small Scale                                                                  spatially referenced data for addressing planning
   Earth is represented by a small area on the map
                                                                              and management problems.”
                                                                                     (Precision Farming Profitability, Purdue University, 2000)
   Generally show less detail
   Used to show regional, national, global data




                                                                                                                                                        1
    Geographic Information Systems                                                  Basic GIS Concepts
                                                                         There are two basic types of information
  A computer based approach to creating maps
     Multiple layers can be used                                    Spatial data –Describes the location and shape of geographic
                                                                  objects and their spatial relationships to other objects
     Different colors and symbols to identify different objects
                                                                    Attribute data – Provides information about these objects, such
                                                                  as the name of a street
  Can combine aerial photography with traditional
  map features to create hybrid maps
                                                                                                                County       Population
                                                                                                                ----------   ---------------
                                                                                                                Alcona       10,889
                                                                                                                Alger        10,009
                                                                                                                Allegan      100,094
                                                                                                                Alpena       30,752
                                                                                                                Antrim       20,901
                     +                     =                                                         Related    Arenac       16,398
                                                                                                                Baraga       8,494
                                                                                                                Barry        53,518
                                                                                                                Bay          110,570
                                                                                                                Benzie       14,286
                                                                                                                Berrien      161,421
                                                                                                                Branch       43,189
          Map              Aerial Photo          Hybrid Map              Spatial data
                                                                                                                 Attribute data




           Vector versus Raster Data                                          Spatial Data Features
• Point              Vector                    Raster                Vector data
                                                                      - discrete geographic objects (features):
                 Point (x,y)              Cell (x,y)
                                                                        Points example: wells, sample locations, city centres
                                                                        Lines example: streams, roads, power lines
• Line
                                                                        Polygons example: countries, land use areas, soil types


                                                                      Raster data
• Polygo                                                               -continuous surface (grid data):
  n                                                                    Example: images, weather maps, elevation maps




          GIS Data Representation                                             Surfaces and Images




 Point
          Line
                  Polygon
                                                                                                                Rogers Memorial Farm (Eagles, NE)




                                                                                                                                                    2
                Data Georeferencing                                                           Dot Map
     Assigning geographic coordinates using a                                  Choosing different ways of displaying the data
                                                                                 affects the information value of the map
         known coordinate system (datum)

  Scanning or digitising gives
  coordinates for every
  geographic feature in paper
  map units
  Known geographic
  coordinates are needed for
  several (minimum three)
  registration (control) points
  spread around the map                                             1 dot = 200,000 people                    1 dot = 1,000,000 people
  These points are used to
  transform the entire map to
  a recognized geographic
  coordinate system




                         Dot Map                                                             Line Map
    Size of the dot can illustrate the quantity associated
       with the geographic objects represented by it




                                                               Lines color coded based
 Population                                                         on functional
     10,000 – 20,000                                           classification of roads
     20,000 – 30,000
     30,000 – 40,000
     40,000 – 50,000




                       Area Maps                                             Data Collected with GPS
                                                                                                               Latitude
                                                                                                  Longitude                       Sensor Data
Different colors can denote that the regions are different,
      with no values comparing them to each other




                                                               Map created using a
                                                              sensor connected to a
                                                              GPS for georeferencing

                                                               Aerial photo used
                                                                as background




                                                                                                                                                3
       Data Creation by Tracing the Map                 Data Creation from a Table


                                                Table
Digital Raster Graphic (DRG)
                                                • City Name
  Elevation
  Rivers
                                                • Longitude
  Cities                                        • Latitude
  Section/Township/Range


                                                                                  Data in table
                                                                                     Located on map




         Identify Feature and Information               Precision Agriculture Data
                                                 •   Digital Orthophoto Quads (DOQ)
                                                 •   Soil Survey Geographic (SSURGO)
                                                 •   Digital Elevation Model (DEM)
                                                 •   Past Management and Climate Data
                                                 •   Field Boundaries
                                            y
                                         tif




                                                 •   Yield Maps
                                       en




  Information about an
                                       id




object is stored in a table
                               click
                                                 •   Remote Sensing Images
      along with the
 geographic coordinates                          •   Electrical Conductivity Maps
                                                 •   Soil Maps




           Digital Orthophoto Quads (DOQ)            Soil Survey Geographic (SSURGO)
    1999 DOQ
                                                                                         Saunders
                                                                                          County,
                                                                                         Nebraska




    2001 DOQ



Agronomy Research and
 Demonstration Center
     (Mead, NE)




                                                                                                      4
                    Remote Sensing                                Digital Elevation Model (DEM)
                                                                        Topography Maps
• Satellite/aerial imagery (visual, NIR, panchromatic)
• Digital or scanned photographs                            • Downloadable DEM
                                                            • Elevation map
                                                              – Laser sensor
                                                              – RTK GPS receiver
                                                              – Yield maps

                                                                                     Elevation




                      April                     September                                Slope




                Self-Generated Data
   • Yield mapping               • XYZ data
   • Soil sampling
                                 • Delimited text files
   • Soil electrical
                                 • Proprietary formats
     conductivity mapping          for yield data
   • pH and other on-the-
                                 • Interpolation is
     go sensing                    important
   • Scouting




                                                                      http://bse.unl.edu/adamchuk
                                                                      E:mail: vadamchuk2@unl.edu




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