LEARN ILWIS AND TEACH OTHERS IN ONE DAY

LEARN ILWIS AND
TEACH OTHERS IN
ONE DAY
ILWIS PRACTICAL MANUAL
This Practical Manual Covers Just A Brief Introduction To Remote
Sensing And All You Need To Know About Ilwis
ONIDEX GEO-SPATIAL SOLUTIONS
Onidex Geo-Spatial Solutions
Tel: 08067220935, 08085786295
Email:
onidexgeospatialsolutions@gmail.com

Onidex Geo-Spatial Solutions [LEARN ILWIS AND TEACH OTHERS IN ONE DAY]
O n i d e x G e o - S p a t i a l S o l u t i o n s Page 1
What is Remote Sensing?
So, what exactly is remote sensing? For the purposes of this tutorial, we will use the
following definition: "Remote sensing is the science (and to some extent, art) of acquiring
information about the Earth's surface without actually being in contact with it. This is done
by sensing and recording reflected or emitted energy and processing, analyzing, and applying
that information."
In much of remote sensing, the process involves an interaction between incident radiation and
the targets of interest. This is exemplified by the use of imaging systems where the following
seven elements are involved. Note, however that remote sensing also involves the sensing of
emitted energy and the use of non-imaging sensors.
1. Energy Source or Illumination (A) – the first requirement for remote sensing is to have an
energy source which illuminates or provides electromagnetic energy to the target of interest.
2. Radiation and the Atmosphere (B) – as the energy travels from its source to the target, it
will come in contact with and interact with the atmosphere it passes through. This interaction
may take place a second time as the energy travels from the target to the sensor.
3. Interaction with the Target (C) - once the energy makes its way to the target through the
atmosphere, it interacts with the target depending on the properties of both the target and the
ecording of Energy by the Sensor (D) - after the energy has been scattered by, or emitted
from the target, we require a sensor (remote - not in contact with the target) to collect and
record the electromagnetic radiation.
5. Transmission, Reception, and Processing (E) - the energy recorded by the sensor has to be
transmitted, often in electronic form, to a receiving and processing station where the data are
processed into an image (hardcopy and/or digital).
6. Interpretation and Analysis (F) - the processed image is interpreted, visually and/or
digitally or electronically, to extract information about the target which was illuminated.
7. Application (G) - the final element of the remote sensing process is achieved when we
apply the information we have been able to extract from the imagery about the target in order
to better understand it, reveal some new information, or assist in solving a particular problem.
These seven elements comprise the remote sensing process from beginning to end. We will
be covering all of these in sequential order throughout the five chapters of this tutorial,
building upon the information learned as we go.
Enjoy the journey!

PRACTICAL CLASS
ILWIS 3.3
Install ILWIS 3.3
After a proper installation, (lunch ILWIS 3.3) interface of the below comes up;
 Create a working folder (in your C-Drive)

TO IMPORT FILE(s)
Import Via Geogateway
Goto file>Import>Via GeoGateway
Comes up this interface
Click on this folder 3 times until(Recyclebin folder comes up)

Then Goto Vietnam(scroll down to locate your Vietnam file)
Click on import format
 Choose Tagged image file format to see all (.TIF) file.
Click on nn1.tif (i.e band_1), give-output filename (e.g band_1)

Choose a working folder(e.g Vietnam) and click on ok.
Give the Output filename as (e.g band_1)
Choose an Output folder

Click on Show Convert to ILWIS data format and then click ok
The result displays as the below
Repeat same steps for other bands

COLOUR COMPOSITE
Goto Operation>Image Processing>colour composite
Choose your band combination by clicking on the dropdown arrow (e.g. band_5, band_4 &
band_3)
Type your Output Raster Map (e.g band_543)
Then click on show.

Then comes up this interface, on this particular interface always remember to click on
create pyramid and then click ok
The result displays as;
Can you see how beautiful the result is?
Different band combinations are used depending on what your interests are. We
have band combinations that will show much of the vegetation in an area, or
settlements or river, lithology and so on.
The next topic is to let you know how to cut out you area of interest from the entire
Image (map) which we refers to as submap.

To create submap
Creating submap is simply narrowing down to your own area of interest. Let’s go through an
example for a better understanding.
 Choose your band from navigation
Goto File>Create>Submap
 Zoom to the require area of interest covering the entire area you want to work on.

Get the top right values by placing your mouse at this corner e.g (957, 4838)
Top right values
The values appears here opposite diagonal values
The values are achieved by computing in this form, subtracting them from one another to get the
actual values to use for the submap.
 Get the top left values e.g. (957, 4838)
 And the opposite diagonal values e.g. (745,1030)
After getting these values, click on Corners on the Submap interface and you can insert the figure
as follow; First Line=975, First Column=4838, Last Line=745 and Last Column=1030
Always remember to give it an output name;
 Now click on File>Create>Submap
Fill the obtain values in
each boxes e.g. (957,
4838) and (745,1030)

IMAGE CLASSIFICATION.
SUPERVISED CLASSIFICATION
 First get the choice image to work on.
 Goto Operation>Image processing>Colour Separation
 Choose (required image) under Raster map
Repeat same steps for other two colours (i.e Green and Blue)
Click on the dropdown arrow and select/choose
the required image (e.g. sub-band_543)
Select a colour (e.g. Red)
Name the output raster map as(e.g. sep543_r)
Then click on show

Goto file>create>map list
When done with that, comes up this interface;
Here, you will do the following;
 Give a suitable map list name e.g Vet_list
 Now choose your different colour separated images (i.e sep432_r, sep432_g, sep432_b)
 Now click on the button with arrow to the right for each sep_files.
 Goto file>create>sample set
Click on this arrow to add to add
the required sep_file in the other
of RGB(i.e red green and blue)
In in case of any mistake, you are
not yet lost just click on this arrow
for the removal of any file.

Now click on sample set
On this interface, you will do the following;
 Give sample set name (e.g Vet_set)
 Now search for your vet_list by clicking on the dropdown arrow on map list.
While done with that, comes up the interface below
Here you will do the following;
 Look for plus(+)sign, click on it
 Now decide how many classes you want to have.
 Give name (e.g vegetation) code(vgt) and describe (green)
 Also click on (+)sing –add items again
 Then do for the following.
Name Code Description
Water body wtb blue
Settlements stl brown
Roads rd yellow
Bare soil bs red
Rocks rck black
Here you can add as many features you are interested in mapping.
When you are done click on exit on that interface.
1. Sample set name as (e.g. Vet_set)
3. Click on this small box with yellow
triangle & give domain name as vet_list
2. MapList (choose the map list you
created initially by clicking on the drop
down arrow)
Now click ok on this interface

Now re-arrange the sep543_r, g, b in order of rgb format
The image will appear and a box, on that box, always remember to click/check on
create pyramid layer
Comes up the interface below on which you will start your classification.
In the above image, you will zoom in to see boxes of same colour and select them using your basic
computer knowledge.

An example is given below
After picking boxes of same colour, right-click and goto Edit, a dialog box comes up
which is shown below this image.

Select what you intend representing the area selected with (e.g. vegetation=green etc.)
The result appears as of the below, do the same for all other areas on the image.

This is an example of the water body
The real classification
Goto Operation>Image processing>classify
Click on the dropdown arrow to sample set
which is the map you are working(I mean
the map in which you have selected your
boxes of same colour)
Put output map as (name of your file)
Click on show

When you are done with that remember to check the box creat pyramid layer and click ok
The result of your work comes up in this form, and you can do samething for other types of
classification apart from box classifier. wish you goodluck.
Now I’m going to teach you how to check your accuracy via confusion matrix.
Goto Operation>Raster Operation>Cross
Comes up the interface below
1st
map as the map you are working
on.
2nd
Map as the map you have done the
classification.
Give name to your output table and
also the outputmap

When you click on show on the above interface, comes up the table below
Goto View>Confusion Matrix
Click on ok

You will have your result display in this format below where you wil see the
following; Average Accuracy, Average Reliablity and Overall Accuracy.
Now you are done with supervised classification.

UNSUPERVISED CLASSIFICATION
This type of classification is also known as cluster
Comes up the interface below, here you are going to select the sep files you saved during
colour separation, which are ( sep_red, sep_green and sep_blue). Arrange them in RGB
format. Also label or give a name to your Output Raster Map.
Click on create pyramid layer and then click on ok

The result displays as this interface below.
For your confusion matrix here, because it’s unsupervised, the computer’s
accuracy is 100%
CREATING LAYOUT
Finally we will learn how to present your result, which might be termed creating
layout.
we are going to use this map as an example. This is your result but you need to present
it in an acceptatble way showing details of the map example of which includes (map
scale, legend, map name or title etc.)
For any map you want to creat its layout, first thing is to open the map as the map below

Goto file>Create Layout
Insert
1
2 3
4
5

The summary of the above is explained as follows
 Open the image to create the layout for
 Click on file> create layout
 Type the map view name
 Type the title
 Click ok
 Set the scale of the map
 Click on insert
 Insert all map features
 Legend
 Scale
 Boarder
 North arrow
 Title…
And after which you will Click on File> Export to bitmap
1. Type the file name
2. Resolution (150)
3. Click OK
 For water body
 Click on the river, choose normal pane hand, click on river
 Left-click and drag on water body then right click and choose Edit
 Then choose the water body as the class.
NOTE: Always choose at least 25% of the different classes in the map.
METHOD-1, MAXIMUM LIKELIHOOD
 Goto operation
 Goto image processing
 Click classify
1
2
3
54

Read-up more about classification method.
 Click on dropdown arrow and choose the required sample set
 (e.g Vietniam_set)
 Choose favourite method (e.g maximum likelihood)
 Now write output Raster map (e.g Vet_maxhood)
 Click on show.
METHOD 2, MINIMUM DISTANCE
 Goto operation
 Image processing
 Classify
 Now pick your sample set.
 Click on (choose) minimum distance
 Click on show.
METHOD 3, BOX CLASSIFIER
Repeat as for the method 1&2
To check your accuracy for box classifier
1. Goto operation
2. Goto raster operation
3. Click on cross
TO CHECK CONFUSION MATRIX
While still in box classifier
Accuracy table
Click on view
Click on confusion matrix
Also check for maximum likelihood accuracy.

THANK YOU!
WE BELIEVE YOU ENJOYED IT.
YOU MAY FEED US BACK THROUGH
OUR E-MAIL: onidexgeospatialsolutions@gmail.com

LEARN ILWIS AND TEACH OTHERS IN ONE DAY

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