Welcome to this talk on GIS Applications in
Agriculture.
This is Part 1.
My name is Balaji.
I am presenting this with Mr. Sreedhar who
is a doctoral scholar at IIT-Bombay.
Now look at population data presented in a
tabular format.
On the left, you have villages, the names
of villages.
On the right, you have the census figures
in numbers.
This is one way of presenting it.
This is also a very popular way in newspapers
etc., this is how they present, but there
could be another way.
For example, you can present it as in a map.
You can call it a map in fact.
This data when presented in a map format,
you can see here there are color codes.
They reflect different population ranges.
You can instantly make sense of the areas
that are well populated, heavily populated
and ones that are under populated.
For example, you can see here in this map
that there is actually a city in the middle
of a large number of villages.
Now if you believe the second way, the map
way is a better way of presenting population
data.
You have already got an idea of what GIS is.
What is GIS?
Geographic Information System or GIS, it's
a system designed to capture, store, manipulate,
analyze, manage and present all types of geo-referenced
or geographically referenced data; more generally,
special data and you mix it with non special
data where necessary.
That is GIS.
This is at least our definition.
You know there are many variations in the
way GIS is defined in practice.
What is geo-referencing?
It's nothing.
It's simple.
It's associating something with locations
in physical space.
Very similar to the way in a -- in a graph
on paper, you also see it every point on the
paper with a value of x and the value of y.
That's as simple as that.
Now in like you have coordinates on paper,
you have geographic coordinates.
Every position on the Earth is specified by
a set of numbers.
The popular ones, very well known ones, latitude,
which is -- which is a horizontal line on
a printed map of it, longitude, which are
vertical lines and elevation, which is of
course the height.
These are generally used in geo-referencing
a particular place.
So GIS definition, continuing our discussions
on it, GIS definition is that spatial data
is important in GIS and it includes place,
time and attribute.
Now Geographic data can be of two -- two formats.
One is vector.
The other is raster and they can be different
types like, for example, points, lines and
areas.
We will go into them separately.
A vector data you can see is presented at
the right and the vector data is often generated
when you digitize a paper map.
That's as simple as that.
At the right side you have a raster data,
which looks color coded in some way and this
is generated primarily from satellites.
In fact, most of the satellite derived imagery
is presented as raster data.
What are attributes?
Actually, you should call them thematic attributes.
For purposes in agriculture, you can say weather
is an attribute.
Land use a group of other types can be an
attribute.
Hydrography is an attribute.
Socio-economic parameters such as income status,
ownership of assets, they can be thematic
attributes.
Now each theme can be a layer like, for example,
you can have the physical map of an area over
which you lay streets, buildings or even customers
etc.
As you can see here, these are all various
attributes.
So in effect, what is GIS?
It is related to data management.
It's a -- it's a way to relate data.
It's a relational data management.
The key aspect of GIS is spatial data.
The format can be vector or raster.
The type can be point line or polygon.
Visualization is an important aspect.
Query and analysis are important aspects related
to GIS presentation and its eventual use in
decision making.
Now we stop here this part and look at the
exercises that we are giving you.
Go to Google Maps.
Visit Google Maps and select a favorite location.
Look at the political map and locate and view
earth, and locate and view the imagery.
now can you say something about the attributes
you found there?
Do that as an exercise.
It's an open-ended one.
The other is you should visit the site called
Wikimapia.
Locate your favorite street.
And if you find that some details can be added
which are useful to others, do add them.
And these are open-ended exercises.
These are not going to be graded, but to help
you get familiarity with this.
There is going to be a Part 2.
If you are interested you should be visiting
that as well.
Thank you.
