FAQ

Please see the following site for the processing level of ALOS-2 imagery.

You can confirm metadata with the summary file (summary.txt) stored in the products.

Meaning

Resampling (rearrangement) generates an intermediate color between the original pixels when performing operations such as enlarging, reducing, rotating, transforming, and changing the resolution of an image.

Types

The table below shows the resampling methods for ALOS-2.
In addition, you can set parameters at levels 1.5 / 2.1 / 3.1.

The table below shows the map directions and processing levels that can be specified for ALOS-2 images.

Direction of Map

Processing level

※Level 2.1 is only good for Map North

The map projection types you can select are as follows.

ALOS-2/PALSAR-2：Enable to set with Level 1.5/2.1/3.1

U：UTM（Universal Transverse Mercator）
P：PS（Polar Stereo）※1
M：MER（Mercator）
L：LCC（Lambert conformal conic projection）※2

DEM (Digital Elevation Model) used for default is as follows.

For Japan

ScanSAR(WD)Mode：AW3D30 (30mGSD)
SM(Stripmap) or SPT(Spotlight)Mode：GISMAP (GIS MAP Terrain(Hokkaido Chizu)、10mGSD)
*If you do not use the default, you can select from GISMAP or AW3D30.

Outside Japan

ScanSAR(WD)Mode：AW3D30 (30mGSD)
SM(Stripmap) or SPT(Spotlight)Mode：AW3D30 (30mGSD)

Shift direction of each sensor is as follows.
The direction of travel of the satellite is a plus value.

ALOS-2/PALSAR-2

・Ascending:
Shift to minus direction = Move to South direction
Shift to plus direction = Move to North direction
・Descending:
Shift to minus direction = Move to North direction
Shift to plus direction = Move to South direction

Level 1.1/1.5/3.1 imageries are not orthorectified.
When observing an area with a high altitude, geographical misalignment due to topographical distortion may increase.

Orbit accuracy affects the position accuracy. When ordering images, you can choose from the following two options.
For [High precision orbit information], images are generated based on the exact position of satellite calculated using GPS several days after observation.
For [Most Accurate and Available], the onboard ephemeris is applied. In this case, satellite positions are approximate and may differ from image using [High pecision orbit information]. Please select this option for immediate delivery.
After fixing the orbit, the confirmed ephemeris will be applied regardless of which option is selected. This will be the most accrurate one.

Please contact to order@alos-pasco.com. Please note the order is not accepted by Platform purchase orders.

Please download from JAXA's website below. You can retrieve various processing levels of data in CEOS or GeoTIFF formats for your evaluation.

ALOS-2 / PALSAR-2
Sample Product

Interferometric SAR (InSAR) analysis is possible.Since ALOS‑4 operates in the same orbit as ALOS‑2, it is possible to perform InSAR analysis by combining data from the two satellites.
However, please note that if the ALOS‑4 data includes blind areas, those areas cannot be observed and will therefore be non‑interferometric.
In addition, please kindly note in advance that ScanSAR data cannot be used for InSAR analysis between ALOS‑2 and ALOS‑4.

It means the "unobservable areas" within the observed data.
In data observed with PRF-fixed, unobservable areas of approximately 10% to 20% may be contained within the observation swath.
The blind areas that appear in the data are published as "blind maps" for both domestic and overseas regions.
For details, please refer to the official JAXA website below.
*Please note that the blind maps are based on nominal values and may not perfectly match the areas in the actual observed data.

■PALSAR-3 PRF Fixed Observation Mode Blind Map

Even for the data "with blinds," the regions outside the blind area can still be used for analysis.
However, if your AOI is located near the blind area, it may be affected, so please take note as a precaution.

Data marked as "Blind: No Information" contains data that does not contain the information necessary to determine whether or not there are any unobservable area (blind). For observations outside Japan, it is not possible to confirm the presence or absence of blind area before purchase, as the required information is unavailable. Please also note that if any inconvenience occurs in data usage or analysis due to scene quality or defects, we are unable to provide returns, refunds, or exchanges. We kindly ask that you review the data specifications and the following notes carefully before purchase.

■《Important》Notice on ALOS-4 Archive Data

■PALSAR-3 Standard Product Information(Ver Dec. 2025)

"Radio Frequency Interference noise removal" is a process that identifies abnormally strong signals as interference waves and removes them from the spectrum of the observed signal.

"Range antenna pattern correction" is a process that corrects brightness differences and phase differences that occur in the range direction due to the antenna pattern.It is applicable to data in all observation modes.
"Azimuth antenna pattern correction" is a process that corrects brightness differences that occur in the azimuth direction due to the antenna pattern. It is applicable to burst processing data in ScanSAR observation mode only.

CC4 uses the cubic convolution method (third-order convolution interpolation) to perform resampling by referencing a surrounding 4×4 grid (16 pixels).
CC6 applies the same method but uses a 6×6 grid (36 pixels). CC6 has higher interpolation accuracy than CC4, but the data size is correspondingly larger.

For ALOS-4 data, you can specify whether to output image files for each polarization.
Please select your preferred polarization files when you order.

"Inter-polarization calibration" is a process that corrects errors that occur between the acquired polarization channels (HH, HV, VH, VV).
It adjusts gain differences and phase offsets between polarizations, as well as corrects crosstalk (signal leakage between channels).