Hello everyone, this is a second lecture,
which is in continuation of a previous lecture in which we I have introduced an overview
of what is GIS. As you know each and every system having different
components, so GIS if you take say example of a pencil then pencil having two major components;
one is your graphite another one is wood. Similarly, in GIS we are having different
components. One more important thing, which I would like
to bring in the previous lecture I have touched little bit about coordinate geometry. The basis of GIS is completely mathematics,
but in this course, we are not going to go into the details of mathematics, but how mathematics
in background is working for us time to time I would be definitely bringing those points. Like yesterday or in previous lecture, we
have discussed about coordinate geometry, the mathematics on interpolation, the mathematics
on set theory, mathematics on different aspects of a polynomial equations and other things
and all are used in GIS. So, everything in the background is a based
on mathematics, but on front end we don’t see those things except the user interface. So, let’s say go into the deep more starting
with different components of GIS. GIS is a if you see different literature or
books or on web pages, you would find people will describe maybe five components, six components
and so and so forth. But I feel that a we can very well segmented,
GIS into five major components, and these components. As you know that in the previous lecture also
we have discussed this figure that because the real world we are segmenting or discretizing
into different layers; in order to do that, so that we can towards the analysis or modeling
or prediction we need to have different components. So, the first component because if you recall
the definition of GIS, it is mentioned that it is a computer based information system. So, it has to have a software as well as a
hardware. So, you know that a hardware is a computer
on which GIS operates. Now, this is very interesting; nowadays, it
is not necessary that you should have super computers, mainframe computers or big computers
for GIS analysis; even on smart mobiles a basic GIS can function. So, GIS say for the hardware wide range of
hardware is available on which GIS can run. There are software which are high end software
or sort of a big softwares which require workstation and the same software a stripped version of
the same software can run on your palm top or laptop or even on your smart mobiles, having
say window operating system or android as well. So, hardware nowadays GIS is available on
all kinds of platforms. And keep the example of a previous lecture
about like a Google map or Google Earth. Google map is also available on variety of
platforms. So, you need to have hardware. And as you know that hardware runs on wide
range of computers and from centralized computers, computers on servers, desktop computers standalone
network configuration all kinds of combinations are available now. So, hardware is one of the most essential
as per the definition of GIS the first component. The next one comes, the software this is another
very important component because without having software you cannot have real GIS operations. Here I would like to give you one analogy,
which is very interesting and the analogy is that GIS is something like a carpenter’s
toolbox. Someone may surprise with this analogy, but
let me explain that you go in the market and you can buy a carpenter’s toolbox, but you
will realize very soon that the carpenter’s toolbox having different tools for example,
it is might be having hammer, saw or a you know to you know maybe drilling machine and
so and so forth. But the carpenter’s toolbox will not have
design; will not have the raw material. So, this is this is very important the similarly
in GIS though you may get hardware you may install a GIS software, but if you don’t
have the data which is our next component then it is useless. And if you do not have designs like for a
carpenter if he doesn’t know how to prepare a chair then your the carpenter’s tool box
is useless for him even if he is having wood that means, the material and in our GIS parallel
we can call it as a data. So, all these five are most essential, and
have to be there together then only a GIS can function. So, the second component that you need the
software to run your GIS operations, so this provides functions and tools needed to store,
analyse, display geographical information that’s the main purpose of your softwares. Now, similarly like GIS softwares are available
again on wide range of platforms and wide range of operating system. As time is passing when GIS was invented by
Roger Thomlinson, at that time it was on deck machines you have to there operating system
where altogether different may be unique or some other operating system. Later on most of the now most popular GIS
softwares are now on window machines which are having very powerful set of tools and
most of the task which you can think in GIS can be performed on a these windows machines
maybe running on workstation or even on laptop. So, the software is basically the purpose
of these softwares-GIS softwares as a displayed here to store, analyze and display geographic
information. Remember all the time everything is related
with coordinates, geographic coordinates location specific coordinates. So, everything which we are handling which
is the unique thing in GIS which is not common in CAD machines or CAD CAM softwares or other
technologies, but only GIS provides that functionality to use geographic coordinates. The key software components within the within
the software the components which we look in GIS software like for input of the data
we would like to bring the data because by definition data might be coming from variety
of sources. And therefore, your GIS software should be
capable of receiving data from variety of sources. Here variety of sources as mentioned earlier
that maybe the field data, maybe the remote sensing data, maybe the data coming from some
excel sheets, maybe from already existing databases, which is or maybe analog data,
which has to be converted onto in to GIS platform. So, the input capabilities, good GIS software
should have very good input capabilities; some time you even have to key in the data
within the GIS database. Now also it should allow us to manipulate
the geographic information; manipulation doesn’t mean that we are corrupting the data. Manipulation means changing from one format
to another for example, like from analog to digital, digital - one format digital to another
format like in a images be to sometime we get images in tiff format we convert them
to maybe jpg format or img format depending on the requirements of individuals softwares. And then your another key component within
the software is the database. So, good GIS softwares should support a very
good database management system. Third is the tools for support geographic
query, because ultimate aim after developing the database bring the data inside the data,
organizing the data in a efficient manner then comes the query, analysis and visualization
output which you are looking. So, your GIS software should support all these
things. And the last in this one is that it should
have nowadays it is required, in earlier versions everything was through command mode. So, everything has to be typed now all it
is through windows or a GUI interface. So, you you are having a easy access to these
tools very easily. One one very important question comes here
that some suppose somebody is looking that a he will start working on GIS, because the
project or the problem on which he is working he feels that he can use GIS to solve those
issues. Now, the next question will come in this mind
that which software because in previous lecture I have mentioned there are hundreds of softwares
available. So, which software? Now, I can give you some criteria on which
one should judge and then buy or arrange those softwares. The first criteria in my opinion is that the
software should be modular fashion that means, today you are having certain amount of funds
you buy the software. Now, tomorrow you are having more requirements,
you are having again some funds available, so you buy another some add-on or modules
which can very well gel with your existing basic installation of GIS software. Another very important thing with GIS software
is that you should have good help available, nowadays most of the very popular GIS softwares
are having either online help or offline help available through the, but if the softwares
which are not providing online help then they I would not put them in a very good category
of GIS softwares. Another very important thing is that because
sometimes locally you may not be having expertise available within your organization. So, you sometimes when you are stuck in GIS
in real projects, this is a very common thing that initially when you start working in GIS
platforms, you find sometimes difficultly while inputting the data organizing the data
or analyzing the data then you would look for help online help or offline help may not
be sufficient. So, you would look some help by through some
person. So, these softwares GIS softwares should also
support some discussion group nowadays good softwares are having their own discussion
groups, so that you can raise your question and within few hours maybe 24 hours later
you get the good answer, good reply, and good support from these discussion groups. Sometimes you can also contribute or help
others if you know the answer about that particular problem by that person has raised. So, these are the certain criteria one should
keep in mind when going or selecting GIS software. Now, third and in my opinion again very important
component is the data as for the carpenter is a wood or material which he will use to
prepare a furniture. Here we will make maps, or tables or reports;
without data you may be having good hardware you may be having very most popular and most
advanced GIS software, but if you do not have the data it is no use. So, data is another very, very important and
that is why it is mentioned here that the possibly the most important component of GIS
is the data. Without data your GIS cannot run like without
wood carpenter cannot work. Now, GIS data and related a tabular data which
I will come later which we call as non spatial data geographic data we call as a spatial
data can be collected in house as a by definition coming from variety of sources. So, one might be in-house collection or purchased
or available through some a sources. So, data can come from variety of sources
in variety of formats and that is why a manipulation format conversion you know all kinds of conversions
may be required in case of the data. Now, the fourth and another important component
the people, without people, now people includes both the GIS experts and users and decision
makers all kinds of you know a full spectrum of people are required in a GIS. Otherwise, if there is nobody is an asking
new solution from GIS then development of GIS will stop. So, you require as users purely as users end
they do not know how GIS works; they do not know from where the data has come, they do
not want to bother that how you have organized the data. They just want to see the result like most
of the people are using Google maps without knowing from where the data is coming, who
is generating the data, they are just simply users. People also include the GIS experts those
who collect the data, organize the data and maintain such systems maybe online systems
like Google map or maybe offline systems in some organizations or large enterprise. So, people are another very important component
of GIS. And GIS technology will be limited as I have
already mentioned without the people and who will manage the system develop plans for applying
into the real worlds. And the real users who would really exploit
the GIS, and GIS users also range from technically specialists who design or write codes develop
the software further and those who keep asking questions to the GIS expert that can you do
this thing. And also mention in previous lecture there
is a continuous process GIS operations are continuous you keep a developing something,
people will keep asking more; and as you develop more they will keep asking more. So, they will compel the development this
is how the GIS has developed. So, it is in many ways it is good. Another very important thing when we start
looking little bit to the first component in the hardware or computer technology overall
which you also include the software technology that more developments when they are taking
place in these two hardware and software slowly in after some time these development will
also come into the GIS platform. So, the development in any such fields, ultimately
will also peculate into the GIS domain and more hardware's are improving and becoming
better faster and are capable of handling large volumes of data then our GIS also becomes
rich. If softwares becomes very efficient new algorithms
are developed new tools are there then slowly slowly all these will finally, and ultimately
also will perculate into GIS domain. So, here GIS is getting benefited from all
sources, whether it is a cartography any development takes place in cartography ultimately it will
perculate into a GIS. Any development in computer science software,
hardware or in communication that to will come. Similarly like in GPS technology, three years
back we had only one global positioning system which was US based. Now we are having several including India
is having our own GPS system like which we recently it has been renamed as NAVIC it was
IRNSS system and it is a regional system whereas, GPS or Gluons are global system Chinese have
also developed a system which is called Beidou, so these that is global system. Now, a GPS receiver, which used to receive
only signals from US based GPS or global positioning system,is may not be use in future. Now, people are having a receivers which can
receive signals from three four such systems, therefore the accuracy will improve. And this improvement in accuracy ultimately
will also peculate into GIS; new applications also will develop in GIS. One very important thing in GIS regularly
including remote sensing digital image processing we do is geo referencing; we do geo code a
satellite image. So, because nowadays we are moving from higher
and higher resolutions and therefore, very high quality or very accurate geo referencing
is required. So, conventional methods of geo referencing
may not work now. So, we require very high accurate data from
GPS, and luckily all kinds of navigation systems are now available. So, we can definitively improve our accuracy
of geo referencing. So, what I am trying to say that development
in computer technology development in GPS technology, development in remote sensing
technology,development in cartography or cad cam design all finally, will also peculate
into GIS domain. Fifth and last, but not the least component
of GIS is methods. Again, let me relate with the same carpenter’s
toolbox analogy. It is the design of the furniture. How to cut a wood, how to polish a wood, how
to make a hole in the wood, which wood will be more suitable, where one can find the wood,
so all these methods are very much required. In GIS like algorithms are there and as I
have said that most of the things are coming from mathematical domain. So, if anything develops there if it has got
use in GI it will come in GIS, maybe little later definitely it has come. So, methods or designs are very, very important
in GIS. Now a successful as I mentioned here the successful
GIS operates according to a well-designed plan business rules, and which are the models
and operating practices unique to each other. Let me give you one example like somebody
if he is working on say ground water flow, in new model on ground water flow estimation
has come. It does not have so far any linkage with GIS,
but very soon in future it will have a linkage; and once it develops the linkage that model
itself becomes powerful and so GIS becomes enriched because of the linkage which has
been established with that model. And this is how initially all these models
are developed in isolation, one more example I can give there is a very famous a model
which is called universal soil laws equation model. So, this model was existing before the invention
of GIS, but once the people have clubbed it or integrated with GIS that is the same USLE
or universal soil law equation model or revised version are USLE other things have become
much more powerful much more useful once they got the linkage with the GIS. So, there might be some tools available, models
might be available in isolation. There may not be any linkage so far with GIS,
but in future in my opinion they will have very good linkage if they handles the geographic
data and then the tool itself the model itself becomes powerful. So, the GIS so that is now in methods, methods
have the input in data methods have about the you know organizing the data, methods
about the changing the format, methods have about geo referencing accuracy parts and then
finally, analysis and modeling. So, these come and so these section of software
GIS softwares slowly, slowly are also becoming very enriching. Let me one give you one more example like
GIS handles large volumes of spatial data and sometimes you require data compression
techniques. Now data compression is a part of mathematical
domain. So, more developments as they are taking place
more new technologies which they are implementing in data compression ultimately ends up in
GIS. For example,web based data compression techniques,
they have now peculated into GIS softwares. And GIS softwares will compress the data or
sometimes you one has to buy a different compression tools available elsewhere you compress the
data, decompress the data. So, they say all together different domain
or a branch or mathematics, but the benefits which are being developed in mathematical
branch or data compression also are coming later on little later into GIS platform so
in image processing or the remote sensing as well. As I mentioned in the first lecture that we
you know segment that natural ward into different components, different layers, different themes
and this is how that we organize the data into geographic means we attach the location
with each object. The object may be point data, object maybe
the line data, polygon data or maybe image satellite image or a photograph or a video
or aud io, everything we try to attach with the coordinates
and those coordinates are geographic coordinate. In our domain, we call as may be latitude
longitude or in some other map projections may use different coordinates system, but
all will fall in the geographic coordinate. And all these layers are organized in that
fashion and then referenced the geo reference I have mentioned already, so it is reference
with the coordinate geographic coordinate, so that we can extract all layers and top
of each other. And whenever we want to use out of say I am
having in my database 20 layer I want to use two or three or four at a time, I can very
well use in GIS once they are geo reference to the geographic coordinate system. Any coordinate system, which we can use, means
many in projections system I mean here. And as I mentioned also earlier that the geo
spatial data. So, the data which goes into the GIS can be
divided into two major parts one is which is spatial data which is having a real the
object location. For example, you are having a location of
a house, now location of a house is having x and y coordinates maybe also z coordinate,
but z coordinate is a will go as a non-spatial data. How many people are living in that house,
who owns the house, when it was constructed all kinds of information will go into non-spatial
data and the spatial data is having just location. So, I give the example of point data, it will
have just x and y. If it is a line data it will have a series
of x and y. And if it is a polygon data then it will have
a series of x and y, but the first coordinate and the last coordinate is going to be the
same. So, a like in case of satellite images, the
location of a pixel will become very spatial data, but the value of the pixel will become
your non-spatial data or also we called as attribute data. And the spatial data will answer your question
that where is it the location, because it is having holding the location of an object. Whereas the non-spatial data will answer the
question like what is it? So, like wise we keep organized the data in
a fashion in GIS in a manner, so that we can retrieve very efficiently we can analysis
in a very coherent and nice manner. Now as you know that this thing we have touched
little bit that the real world we try to segment it in different time types of data which in
the next lecture we will be discussing what is vector, what is raster and different types
of vector and other things. But we can segment the real world into maybe
some layers of vectors might be having point line, polygons or may be some layers of raster
maybe elevation information maybe a satellite image representing the land use, forest cover
and all kinds of things are there. And then associated non-spatial data or we
call attribute data or in simple terms you can think like a tabular data. So, you are having an object and that object
is suppose this is x, y, this is one point. So, it will have one x and y. So, it is just having location, it is a spatial
data, but this point can have a table attached table like this. And can have say unique id which is essential
for all spatial objects then you will have a maybe the z location, maybe the owner if
it is a information about the house maybe the owner when it was constructed and so on
and so forth. Now this part theoretically is unlimited that
number of columns which you can have in your database in GIS database extended GIS database
theoretically is unlimited, but a when you are really using a GIS software then there
might be some software limitations are there. So, one has to be little careful while creating
more fields against one single spatial object. Similarly, the same similarly kind of table
can also be in case of a road or a street which is representing a line or polyline and
similarly for an area you can have attribute table. So, attribute table will always store non-spatial
data which is directly related with the spatial objects; it is not that it is lying in isolation
and that is the beauty of GIS that spatial data and attribute data are having a direct
linkage or dynamic link or hot link. Otherwise, like in like cad systems, you do
not have the database here you are having database as well as a spatial object. So, this brings end of this presentation on
components of GIS as mentioned in the beginning that in literature you might find few more
components, but essential components I have already discussed here. Thank you.
