well come to all
Govardhan LodhaB.Sc.(Ag.) Final Year
J. N. Agriculture University, Jabalpur College of Agriculture, Tikamgarh (M.P.)
GIS Operation and Data Formation in GIS
Image: NASA 2005
GOVARDHAN LODHAAKASH SONKUSALE
SUBMITTED TO :-
Dr. M. L. KewatAssociate Professor
PRESENTED BY :-
PRESENTATION ON
JAWAHARLAL NEHRU KRISHI VISHWA VIDHYALAYA JABALPUR M.P.
College of Agriculture, Jabalpur
Slides • Introduction• GIS Operations• How does GIS work?• Types of data• Data Representation • Working with GIS• An overview of GIS Image
What is GIS?
1
Geographic Information System• Geographic – 80% of government data collected is
associated with some location in space
• Information - attributes, or thecharacteristics (data), can be used to symbolize and provide further insight into a given location
• System – a seamless operation linking the information to the geography – which requires hardware, networks, software, data, and operational procedures
…not just software! …not just for making maps!
• Many More to Come… Environmental impact assessment Resource management Land use planning Tax Mapping Water and Sanitation Mapping Transportation routing And many more ...
GIS Operations -
How does a GIS work?• GIS data has a spatial/geographic
reference
This might be a reference that describes a feature on the earth using:
• a latitude & longitude• a national coordinate system• an address• a district• a wetland identifier• a road name
Types of data Two types of data are stored for each
item in the database• 1. Attribute data:
Says what a feature is• Eg. statistics, text, images, sound, etc.
• 2. Spatial data: Says where the feature is This also of two types - 1. Vector data2. Raster data:
Types of Spatial data• Vector For discrete data represented as
• Points• Lines• Polygons (zones or areas)• A series of x y coordinates
• Raster • Grid and cells• For continuous data such as elevation, slope,
surfaces
A Desktop GIS should be able to handle both types of data effectively!
Raster
Vector
Real World
Data Representation
• A GIS stores information about the world as a collection of thematic layers that can be linked together by geography
Polygon 3 Scrub 17 Very high Clay
Geography and Databases
GIS provides Data Integration
VectorsTopology
Networks
Terrain
Surveys
Images
CADDrawings
Annotation
Addresses
27 Main St.
Attributes
ABC
107’
3D Objects
Dimensions• Roads• Land Parcels• Population• Utilities• Land Mines• Hospitals• Refugee Camps• Wells• Sanitation
Working with GIS
Data formation in GIS Capturing data
Scanning: all of map converted into raster data Digitising: individual features selected from
map as points, lines or polygons Geo-referencing
Initial scanning digitising gives co-ordinates in inches from bottom left corner of digitiser/scanner
Real-world co-ordinates are found for few registration points on the captured data
These are used to convert the entire map onto a real-world co-ordinate system
Generate Image of Real world -
Data on different themes are stored in separate “layers”.
As each layer is geo-referenced layers from different sources can easily be integrated using location.
This can be used to build up complex models of the real world from widely disparate sources.
An overview of a GIS 3D image -
Questions
Thank You !