Spatial Data Concepts: Introduction to GIS, Geographically referenced data, Geographic, projected and planer coordinate system, Map projections, Plane coordinate systems, Vector data model, Raster data model

1. GEOGRAPHICAL
INFORMATION
SYSTEM
UNIT 1
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2. WE-IT TUTORIALS (PH:8097071144/55)

3. What is GIS
 A geographic Information system (GIS) is a
computer system for capturing, storing,
querying, analyzing, and displaying
geospatial data.
 The ability of a GIS to handle and process
geospatial data distinguishes GIS from other
information systems
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4. applications of GIS
 GIS has been important in
 natural resource management including land-use
planning
 natural hazard assessment
 wildlife habitat analysis
 riparian zone monitoring
 and timber management
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5. components of GIS
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6. Spatial Data? Vs Attribute
Data?
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7. GIS Operations
 Spatial Data Input (Data entry, Geometric transformation, Projection )
 Attribute data management (verification, Attribute data manipulation )
 Data display (Cartographic symbolization, Map design )
 Data exploration (Attribute data query , Spatial data query, Geographic
visualization )
 Data analysis
 Vector data analysis: buttering, overlay, distance measurement, spatial
statistics, map manipulation
 Raster data analysis: local, neighborhood, zonal, global, raster data
manipulation
 GIS modeling (Binary models ”DIFFERENCE ”, Index models “VALUE
CALCULATION”, Regression models “DEPENDANCY”, Process models
”RELATIONSHIP”)
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8. Geographic Coordinate
System
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9. Datum
 A geodetic datum (plural datums, not data) is a reference from which spatial
measurements are made. In surveying and geodesy, a datum is a set of
reference points on the earth's surface against which position
measurements are made, and (often) an associated model of the shape of
the earth to define a geographic coordinate system.
 Horizontal datums are used for describing a point on the earth's surface, in
latitude and longitude or another coordinate system.
 Vertical datums measure elevations or depths. In engineering and drafting,
a datum is a reference point, surface, or axis on an object against which
measurements are made.
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10. map projections ?
 a method for representing part of the surface of the earth or a
celestial sphere on a plane surface.
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11. Types of Map Projections
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12. Projected Coordinate System
 A Projected coordinate system (PCS) is a two-dimensional planar
surface. However, the Earth's surface is three-dimensional.
Transforming three-dimensional space onto a two-dimensional
surface is called projection.
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13. State Plane Coordinate System
 State Plane Coordinate System (SPCS) is not a projection (also
known as SPC, State Plane, and State). It is a coordinate system
that divides the 50 states of the United States
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14. Public Land Survey System (PLSS)
 The Public Land Survey System (PLSS) is the surveying method
used historically over the largest fraction of the United States to
survey and spatially identify land parcels before designation of
eventual ownership, particularly for rural, wild or undeveloped land.
It is sometimes referred to as the rectangular survey system
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15. Vector Data Model ?
 Vector model
 Points,
 lines,
 polygons
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16. TIGER DATABASE
 Topologically Integrated Geographic
Encoding and Referencing
Topology in the TIGER database involves 0-
cells or points.
1-cells or lines, and 2-cells or areas.
Address ranges and ZIP codes in the
TIGER database have the right- or left-
side designation based on the
direction of the street.
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17. Raster Data Model
 a raster is divided into rows, columns, and
cells. Cells are also called pixels with images
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18. Why use Raster
 Overlay Analysis/Overlay Operations
 Arithmetic Operations
 Addition
 Subtraction
 Division
 Multiplication
 Logical (Boolean) Operations
 Where conditions occur or do not occur together
 AND, OR, NOT, GT, LT, etc.
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19. TYPES OF RASTER DATA
 Satellite Imagery
 Digital Elevation Models
 Non-USGS DEMs(plotting)
 Global DEMs(global scale)
 Digital Orthophotos
 Bi-Level Scanned Files(scanned image)
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20. Encoding types in Raster
 Cell by Cell Encoding
 Run-length Encoding
 Quad tree
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21. END OF UNIT 1
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