ilwis manual, ilwis practical, ilwis guide, onidex geo-spatial solutions (ilwis3.3) manual

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: [email protected]

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!



Page 2

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)



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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)



Page 4

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)



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Choose a working folder(e.g Vietnam) and click on ok.

Give the Output filename as (e.g band_1)

Choose an Output folder



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Click on Show Convert to ILWIS data format and then click ok

The result displays as the below

Repeat same steps for other bands



Page 7

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.



Page 8

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.



Page 9

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.



Page 10

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)



Page 11

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



Page 12

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.



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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



Page 14

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.



Page 15

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.



Page 16

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.



Page 17

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



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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



Page 19

When you click on show on the above interface, comes up the table below

Goto View>Confusion Matrix

Click on ok



Page 20

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.



Page 21

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



Page 22

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



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Goto file>Create Layout

Insert

1

2 3

4 5



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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

5 4



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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.



Page 26

THANK YOU!

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