Lab 1 Create the Imagine Data (file) from Binary (Byte) Data

ranchocucamongabrrrAI and Robotics

Nov 6, 2013 (3 years and 9 months ago)

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1

Lab
1



Create
the
Imagine Data

(file)

from Binary (Byte) Data

Introduction

Image data are in binary format, and are stored as continuous 1
-
D array in a computer.
You just can not

open the files using the WordPad. If you did, you would get weird items on your screen; first you may have to wait
for a while and then you may see some weird symbols.

To the extreme, your compute may become “Not
Responding”, and you may have to re
-
boot t
he computer. The bottom line, you need to import into a particular
format that will be understood by your s/w.
To use them by an image processing and GIS s/w such as the Imagine,
one needs to convert the continuous 1
-
D array data into a 2
-
D image.
Dependin
g on how and where you get/order
the data, and what format your data is and whether your s/w can read the data directly. In general, the s/w you have
may include the known formats. However, if you only have an old version of a s/w that does not understand
or
support the formats of the data you want to analyze. Then, you may have to go back to the basis by figuring out the
data type (one byte, two bytes, floating, etc), and image dimensions (# of lines or rows, and # of columns or
samples).
For data of a sin
gle band, once we know the image size (# of rows by # of columns), we can easily
transfer the 1
-
D array data into a 2
-
D image. For a multi
-
band data, we need to know the # of bands and images size.
Each band may be stored in a separate file. In this lab,
w
e will import
binary data of three Landsat 7 bands into the
Imagine
by using the # of rows, # of columns, and # of bands, as well as other metadata
as an example.

(Doing the
hard way.)

Also, i
f we
were importing

all 8 bands of the Landsat 7 data, we would
spend a lot time to wait for the
processes to finish
.

The data to be imported were acquired on the 28
th

of July 1999

and covered part of e
astern North
Carolina. Since data of each band is in separate file, they can be considered as a band sequential (BSQ)
format. After
we import the three
-
band data correctly into the Image s/w, we need to add accessory information or metadata such
as pixel resolution, project, coordinates, etc. to the imported image so that one can analyze them easily.

Then,
we
will import
a dataset with a format that is accepted or understood by
the

s/w.

Part 1,
Import
ing

three
-
band Landsat TM data (ban
ds 1, 2, and 3)

i)

Start the program.

C
lick on the "
Manage Data/
Import

Data"
to open "Import
" dialog box (Fig. 1)

and
navigate to where the
bin
ary data are stored. You need to decide where to store/write/output the imported image. (Navigating yourself to
your flush drive would be an option for sav
ing

the imported file.) M
ake the selections as indicated

(Fig. 1), and
C
lick on the “OK” to proceed,
which opens the "Import Generic Binary Data" dialog box (Fig. 2). Set the “Data
Format” as the BSQ, “Data Type” as the Unsigned 8 Bit, “# Rows" as 6991, "# Columns
" as 7821, and "# Bands as
3".
The data type, # of rows and # of columns come from the data’s

metadata file
,

“l71015036_03619990728_mtl.l1g”.
Answer question 1.


2


Fig. 1.




Fig. 2.


ii)

Then,
click on the “Bands in Multiple Files” to open the “BSQ Band Files” dialog box (Fig. 3); now we will
add the rest two bands:

i)

C
lick on the up
arrow to change the “Band #” into “2”, select the 2
nd

band file
“l71015036_03619990728_b20.l1g”, and then click on the “Set”; band 2 has been added for importing
(Fig. 3).

(You may need to navigate to the folder where the data are stored.)

ii)

C
lick on the up
arrow to change the “Band #” into “3”, select the 3
rd

band file
“l71015036_03619990728_b30.l1g”, and then click on the “Set”; band 3 has been added for importing
(Fig. 3).

iii)

The filename, 1
st

two letters l7


Landsat 7,
skip next number
,


1


(I am not sure w
hat stands for),
next
three digits 015


path number identifier, next three digits 036


row number identifier, next three digits
036


row number identifier again, next 8 digits 19990728


year, month, and day, next letter b


band,
next digit


band numb
er.

Make sure the order of your imported image is b10, b20, and b30 as shown
(Fig. 3).

iv)

C
lick on the “OK” to close the “BSQ Band Files” dialog box to finish (Fig. 3).

iii)

C
lick on the “OK” to close the “Import Generic Binary Data” dialog box (Fig. 2), and t
o
start the import
.


3


Fig. 3, three pairs of black arrows on the right point to order of bands 1, 2, and 3.

View the imported image

In an o
pen
ed

a viewer window
,
right
-
click
/Open Raster Layer … to open the dialog box of “Select Layer
To

Add”, and navigate to the folder where the imported file stored. Then double
-
click; the file should be loaded
inside the viewer window. T
he image imported is of 6991 rows and 7821 columns
. Thus, depending on the size of
your viewer window,

you may have a
black viewer
-
window when you display the imported image
. Zoom
-
out if you
want to view the entire image.
If you ha
ve imported the data correctly,
you should see the
zoom
-
out Landsat
-
7 TM
image of e
astern North Carolina. Otherwise, you need to re
-
import the
data until it is the right image.

Add the accessory information to the imported image

Once the image has been successfully imported, you need to add the accessory information for future use
and analysis of the image. Let’s add the information. In a viewer
window where your imported image is

displayed
,
click on the “i
, Layer Info
/View/Edit Image Metadata”

to open the “ImageInfo” dialog box (Fig.
4
).

C
lick on the “Edit/Change Map Model…” to open its dialog box. The information needed to make the
changes is st
ored in the text file, “l71015036_03619990728_mtl.l1g”. Use the Wordpad program to open the file.
Scroll down to find the information (number) to fill in fields of “Upper Left X” or
PRODUCT_UL_CORNER_MAPX in the metadata file, “Upper Left Y” or PRODUCT_UL_
CORNER_MAP
Y

in
the metadata file, “Pixel Size X” or GRID_CELL_SIZE_REF, and “Pixel Size Y” or GRID_CELL_SIZE_REF.
(Here the pixel size X and pixel size Y are the s
ame.) After updating them,
click on the “Projection” and select the
“UTM” from the list, and
also set the “Units
” as “Meters”, and finally
click on the “OK” to finish.

Next, you need to add

the project information. C
lick on the “Edit/Add/Change Projection…” to open its
dialog box. Again, find the information to fill in fields of “Spheroid Name” or

REFERENCE_ELLIPSOID, “Datum
Name” or REFERENCE_DATUM, “UTM Zone” or ZONE_NUMBER
, “NORTH”, and
click on the “OK” to
finish. Right now, the “ImageInfo” dialog box should have all needed
accessory information (Fig.
4
).

Since you have named the output file
, l
71015036_03619990728_b10.img

in the folder you have been
working on, and you have finished all the steps up to this point, the required output file
, i.e.,
l71015036_03619990728_b10.img

has been created. Thus, you can exit the Imagine
s/w and
under the
MS/W
indows environment copy and paste the file
onto your flush drive
.


4


Fig.
4
.

Part 2,
I
mporting the ALOS PRISM data

The
format of the
PRISM data is understood by the

current version of

s/w.

(
s
/w version earlier than 9.2
DOES not understand this format.
That is why as data users, we need to learn how to
“reinvent

the wheel” by
handle
the data using the Generic Binary format, as we have gone through

in the first part of this lab

in case when the
data
format is not understood by the s/w
.
)

Under folder part2, there are four files, IMG
-
*, the image data file, LED
-
*, the
leader file of this volume, TRL
-
*, the trailer file of this volume, and Vol
-
*, the volume file of this volume. (* stands
for all cha
racters of the file names after the “
-
”.)
All four files consist of this data format; you need generally all files
in order for the s/w to read the data correctly.
Fig. 5

shows
how to import the PRISM data into Image s/w.
B
ecause the
format is understood b
y the s/w, the s/w can not only import
the data, but also import the metadata directly.

The PRISM
were acquired on 10/31/2007 and cover eastern North
Carolina. Open a viewer window and view the imported
image.

To view
the imported metadata,
you can
click o
n the
“i
/View/Edit Image Metadata”

to open the image info
dialog box.


Questions

1.

(
1

point
)
There are 6991 rows (lines) and 7821 columns (samples) of one band image. Each pixel of a band is
on
e byte. How many bytes
is

the o
ne band image
?
(Hint:
Under MS
/Window environment

or folder

where you
can see the files, r
ight
-
click on the icon of a file to open the pop
-
up list, select the “Properties”. On the right side
of “Size”, the file size in bytes is shown
within the parenthesis
.)

There are three individual
bands of original
data. What is the total number of bytes of three bands

together
?

2.

(
4

points)
C
orrectly imported
Landsat 7 and PRISM
image
s
.

Each image will be
2

points.

Fig., 5. The dialog box to import the PRISM data
.


5

Acknowledgment


This lab handout was supported by an AmericaView

grant to the East Carolina University

at Greenville,
North Carolina, 27858, USA
. The
LED
-
ALPSMN094172885
-
O1B2G_UN
©

was granted by the Japan Aerospace
Exploration Agency (JAXA) to the East Carolina University.