VEGA Step by Step Manual (1)Last update: 30th May 2023

Visualizing Earth tool by Google Earth Engine Apps (VEGA) is a web-based application empowered by Google
Earth Engine (GEE) which allows you to browse and visualize Landsat, Sentinel-2, Sentinel-1, and ALOS-2
archives without downloading the data or installing any software.
Users of GEE usually write JavaScript code, but VEGA doesn’t require JavaScript knowledge. You can selectoptions or input numbers on the control panel.
Control Panel

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VEGA Step by Step Manual (2)1. Selecting one of the dataset from the pull down menu

Tips (Dataset availability)• Landsat-4 SR: August 1982 – June 1993
• Landsat-5 SR: March 1984 – May 2012
• Landsat-7 SR: May 1999 – April 2022
• Landsat-4 TOA: August 1982 – December 1993
• Landsat-5 TOA: April 1984 – November 2011
• Landsat-7 TOA: June 1999 – April 2022
• Landsat-8 SR+TOA: April 2013 – Present• Landsat-9 SR+TOA: October 2021 – Present• Sentinel-2 SR: March 2017 – Present• Sentinel-2 TOA: June 2015 – Present• Landsat-8 Raw: March 2013 – Present• Sentinel-1: October 2014 – Present• ALOS-2 L2.2: August 2014 – December 2022 (As of May 2023)

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2VEGA Step by Step Manual (3)2. Filter SAR data properties (optional)• Note: Please proceed with this step only in the case of Sentinel-1
selection, Otherwise skip to step 3.
2-1 Filter based on the acquisition modes.
• Choose an acquisition mode from the drop-down menu.
2-2 Filter based on the Orbit pass direction• Choose an orbit pass from the drop-down menu.

Tips (Acquisition mode)1• IW, EW, and SM products are available in single (HH or VV) or dual
polarization (HH+HV or VV+VH).
• IW is the primary conflict-free mode over land with VV+VH polarization.
• EW mode is primarily used for wide-area coastal monitoring includingship traffic, oil spill, and sea-ice monitoring.
• SM mode is only used for small islands and on request for extraordinary
events such as emergency management.

Tips (Acquisition mode)• In the case of the ALOS-2 dataset, this menu is NOT selectable, as thedataset has only available acquisition mode (ScanSAR mode).

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1 Reference: https://sentinel.esa.int/web/sentinel/user-guides/sentinel-1-sar/acquisition-modes

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VEGA Step by Step Manual (4)3. Selecting the visualization method and the band(s)• To visualize black & white image by single band.→see 3-1 below• To visualize color image by multiple bands.
→see 3-2 below

3-1 Selecting a band to visualize black & white (grayscale) image• Choose the band from the drop-down menu. (Leave 3-2 text boxblank)
3-2 Selecting three bands for color composition visualization• Write down respective composition in the “Red-Green-Blue” order,
capital-scale letter, and separated by a hyphen(-) in the text box ( ex:B4-B3-B2 or VH-HH-VH).
To reset and switch between visualization methods, press Reset button.
Tips (Band Information)
Information on the selectable bands for 3-2 is available at thereference slides, or you can also refer them if you press 3-1“Choose a band” button (Make sure not to choose any of them) .
Tips (True Color image)
To make “True Color” image, input the following combination.
• Landsat 4, 5, and 7: B3-B2-B1• Landsat 8 and 9: B4-B3-B2• Sentinel-2: B4-B3-B2
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VEGA Step by Step Manual (5)4. Assigning minimum and maximum pixel value ranges• Write down minimum value(s) in the upper text box, and maximumvalue(s) in the lower text box.
• If you chose “three bands for color composition visualization” at 3-2,
you can input min and max values for respective bands separating
the numbers with comma (,) (ex: 3000,2500,3000)• If the min and max values ranges are the same for each band, one
value can be assigned for each min. and max. values.

Tips (Pixel Values)
For those who use VEGA for the first time:• In optical imageries, 0 for Min and 3000 for Max values are recommended.
• In SAR imagery, -30 for Min and -25 for Max values are recommended
Then, you can change the values and see how the image will look.

5. Specifying the period of observation• Write down the starting date of observation in the upper text box,and the ending date in the lower text box.
• The dates must be written in the YYYY-MM-DD format and must be
separated only by hyphen (ex: 2018-11-25).

Tips (Dataset Availability)
See the tip on page 2 for availability (observation period) of eachdataset.
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VEGA Step by Step Manual (6)6. Selecting Data Composition Method• You can choose reducer (function) to composite the collection as asingle image. Available methods are:
 Median Mean Minimum
 Maximum Latest observation (No reducer)
 Earliest observation (No reducer)

7. Specifying the cloud masking status.
• If you want to mask cloud cover to generate a cloud free image,check “Cloud Masking” box.

8. Load the Image• You can load the image according to specifications assigned inprevious sections.

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6VEGA Step by Step Manual (7)9. Comparison of Visualized Images• VEGA shows and overlays the last four
assigned images (the new image will bethe top layer) and earlier images will
not be shown.
• If you want to hide layers, uncheck its
check box.
• You can change the transparency ofeach layer by moving its slider.
• After loading the image, by checking on
any part of the image, you can checkthe latitude, longitude and pixel valuesof the top layer.

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7Ref: Bands Specifications for Optical Datasets (Landsat series and Sentinel-2)
List of Landsat 4,5, and 7 bands available on VEGA

List of Landsat 8 and 9 bands available on VEGABand Name

Wavelength

Description

Band Name

Wavelength

Description

B1

0.45-0.52 μm

Blue

B1

0.435-0.451 μm

Ultra blue

B20.52-0.60 μm

Green

B2

0.452-0.512 μm

Blue

B30.63-0.69 μm

Red

B30.533-0.590 μm

Green

B4

0.77-0.90 μm

Near infrared

B40.636-0.673 μm

Red

B5

1.55-1.75 μm

Shortwave infrared 1

B50.851-0.879 μm

Near infrared

B72.08-2.35 μm

Shortwave infrared 2

B61.566-1.651 μm

Shortwave infrared 1

B610.40-12.50 μm

Surface temperature

B72.107-2.294 μm

Shortwave infrared 2

B1010.60-11.19 μm

Surface temperature

List of Landsat 8 Raw Images bands available on VEGA

List of Sentinel-2 bands available on VEGABand Name

Wavelength

Description

Band Name

Wavelength

Description

B1

0.435-0.451 μm

Ultra blue

B1

443.9nm (S2A) / 442.3nm (S2B)

Aerosols

B20.452-0.512 μm

Blue

B2496.6nm (S2A) / 492.1nm (S2B)

Blue

B3

0.533-0.590 μm

GreenB3560nm (S2A) / 559nm (S2B)

Green

B4

0.636-0.673 μm

Red

B4

664.5nm (S2A) / 665nm (S2B)

Red

B5703.9nm (S2A) / 703.8nm (S2B)

Red Edge 1

B50.851-0.879 μm

Near infrared

B6740.2nm (S2A) / 739.1nm (S2B)

Red Edge 2

B7782.5nm (S2A) / 779.7nm (S2B)

Red Edge 3

B8835.1nm (S2A) / 833nm (S2B)

Near infrared

B8A

864.8nm (S2A) / 864nm (S2B)

Red Edge 4

B9945nm (S2A) / 943.2nm (S2B)

Water vapor

B111613.7nm (S2A) / 1610.4nm (S2B)

Shortwave infrared 1

B122202.4nm (S2A) / 2185.7nm (S2B)

Shortwave infrared 2B6

1.566-1.651 μm

Shortwave infrared 1B7

2.107-2.294 μm

Shortwave infrared 2

B10

10.60-11.19 μm

Thermal infrared 1

B1111.50 - 12.51 μm

Thermal infrared 28

Ref: Bands Specifications for SAR Datasets (Sentinel-1 and ALOS-2)
List of Sentinel-1 polarizations available on VEGA
Polarization Name

Description

HHSingle co-polarization, horizontal transmit/horizontal receive

HV

Dual-band cross-polarization, horizontal transmit/vertical receive

VV

Single co-polarization, vertical transmit/vertical receive

VH

Dual-band cross-polarization, vertical transmit/horizontal receive

List of ALOS-2 polarizations available on VEGA
Polarization Name

Description

HH

Single co-polarization, horizontal transmit/horizontal receive

HV

Dual-band cross-polarization, horizontal transmit/vertical receive

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For more information on VEGA
and the related training courses,
visit our website athttps://rs-training.jp/ or contact RESTEC

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