ALOS Global Digital Surface Model (DSM)
ALOS World 3D-30m (AW3D30)
Version 3.2/3.1

Product Description
Edition 1.0

January 2021
Earth Observation Research Center
Japan Aerospace Exploration Agency(JAXA EORC)ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table of Contents
1.

Overview ................................................................................................................................ 1
1.1.

2.

Updates History of AW3D30 .......................................................................................... 1

AW3D30 dataset .................................................................................................................... 3
2.1.

File component ............................................................................................................... 3

2.2.

File naming rule .............................................................................................................. 4

2.3.

Latitude dependent pixel spacing .................................................................................. 4

2.4.

Header information file format ........................................................................................ 5

2.5.

Quality assurance information file format....................................................................... 9

2.6.

TIFF tag settings for GeoTIFF product ........................................................................ 12

2.7.

GeoTIFF key settings for GeoTIFF product ................................................................. 14

3.

References........................................................................................................................... 15

4.

Related URLs....................................................................................................................... 16

5.

Point of contact .................................................................................................................... 17i

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Revision record
Edition

Date

Chapter

1.0

2021/1/4-

Contents of revision
Revised new edition (for AW3D30 Version 3.2/3.1)

Past revisions
VersionDate

1.0

2015/3/31

Chapter/
Table
Chp.1

1.1

2.1

2.2

2.2a

3.1

3.1a

2017/3/6

2018/4/25

2019/4/9

2020/2/28

2020/4/2

2020/05/15

Chp.2.1/
Table 1
Chp.2.3/
Table 3
Chp.5

Contents of revisionFirst edition
Addition of the explanation on the void-filling of DSM values in cloudand snow masked pixels
Format definition change of mask (MSK) file
Field addition to quality assurance information (QA) file
Chapter addition for references

Chp.1
Chp.2.1/
Table1
Chp.2.2/
Table 2
Chp.2.2/
Table 2
Chp.2.3/
Table 3
Chp.2.3/
Table 3
Chp.3.1/
Table 5Chp.5

Addition of explanation on the void-filling of DSM

Chp.1

Addition of ver. 2.2 description

Chp.2

Correction for ver. 2.2

Chp.5

Addition of reference URLs

Chp.2

Correction of Table 1 and 2

Chp.1

Addition of ver. 3.1 description

Chp.2

Addition of naming rule and zonal pixel spacing, Correction for ver. 3.1

Chp.5

Addition of references and URLs

Chp.2

Correction of Table 1 and 3

Clarification of file composition contents of AW3D30
Field No.59～64, Clarification of title of the category.
Field No.80, Deletion description of MSK details.
Clarification of title of the category.
Addition of version of source product to QAI file
Correction of fluctuation of description
Addition of referencesii

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

1. Overview
Since 2014, the Japan Aerospace Exploration Agency (JAXA) has proceeded the project to develop the
precise global digital 3D map “ALOS World 3D” (AW3D)*1 covering the global land areas through the use of
3 million scene archives acquired by the PRISM panchromatic optical sensor on the Advanced Land Observing
Satellite "DAICHI" (ALOS) operated from 2006 to 2011. The developed digital 3D map consists of digital
elevation model (DEM) or digital surface model (DSM) that can represent land terrains with approximately 5
meters in spatial resolution and orthorectified PRISM nadir looking images. The digital 3D map have beenutilized in a wide variety of applications such as map development, damage prediction of natural disasters,
and water resource investigation.
Based on the AW3D DSM dataset, JAXA is processed and released the “ALOS World 3D-30m”(AW3D30) DSM dataset, which has approximately 30 meters of spatial resolution. AW3D30 dataset isfree to use for everyone, therefore we hope that this dataset will be widely used in scientific research,education, and new services based on geospatial information.
*1: Chapter 3.References, 1) and 2)

1.1. Updates History of AW3D30
Version 1.0 released on May 2015
The first version of the “ALOS World 3D-30m” (AW3D30).
Version 1.1, March 2017
Void values in the cloud and snow pixels between 60 degrees North and 60 degrees South were filled withexisting DEMs by the Delta Surface Fill *2 method.
*2: Chapter 3.References, 5)
Version 2.1, April 2018
The source AW3D DSM has been upgraded to version 2. Masks of the land water and low correlation pixels
were also filled with existing DEMs in addition to the cloud and snow pixels between 60 degrees north and
60 degrees south. In Japan area, filling was carried out after updating coastline information.
Note that only AVERAGE resampling product is provided from this version since there is not much difference
between AVERAGE and MEDIAN product that were contained in previous version.
Version 2.2, April 2019
This is an improved version of the northern region over 60 degrees north. In this version, along with thecomplement of no-data or low-quality area, updating of coastline was also performed.
Version 3.1, April 2020 (North of 60 degrees south latitude), January 2021 (South of 60 degrees south latitude)
This is a version created by reconsidering the format in the high latitude area, auxiliary data and processing
method.
Different pixel spacing for each latitude zone was adopted at high latitude area. Coastline data, which is oneof the auxiliary data, was changed, and new supplementary data was used. In addition, as a source data forJapan, AW3D version 3 was also used. Furthermore, the method of detecting anomalous values in theprocess was improved.

1

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Version 3.2, January 2021
This is an improved version of 19 tiles at low latitude region. Partial anomaly was corrected by new
supplementary data.
The 19 tiles that replaced version 3.1 are following.
N002W079, N004E100, S001E117, S001W051, S002E016, S002E137, S002W051, S002W053,
S003W044, S003W061, S003W063, S003W064, S004E119, S005W059, S006W064, S006W066,
S007W064 , S008E140 , S008W063

2

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2. AW3D30 dataset
2.1. File component
A tile of this dataset covers the unit area of 1 degree latitude and longitude. The tile ID stands for the latitude
and longitude at lower-left (southwest) corner. For every tile, the set of files shown in Table 1 is stored as a zip
compressed file.
Table 1 File component of AW3D30 dataset
File typeContents and details

Notes

DSM file(DSM)[GeoTIFF format]

Height above sea level
 Integer (signed 16 bit) raster data (little endian) Equirectangular projection
 Pixel spacing: basically 1 arcsec (approx. 30 m), latitude dependent*1
 DSM values are average over the range of 1 arcsec grid pixel(Round off to the integer) Elevation (in meter) converted from the ellipsoidal height based on
ITRF97 and GRS80, using EGM96*2 geoid model Value “-9999” is stored in void pixels
 Value “0m” is stored in sea pixels
Mask information
 Byte (8 bit) raster data Equirectangular projection
 Pixel spacing: basically 1 arcsec (approx. 30 m), latitude dependent Lower 1-2 bit: Valid/Invalid, Mask Information(Cloud and snow, Land water and low correlation, Sea)
 Lower 3-8 bit: Elevation dataset used for the void-filling processing,filled/not filled by IDW method*3*1: Table 1 for details*2: 4.URLs 1)*3: Inverse Distance
Weighted method
3.References 5)*4: Land water and low
correlation mask indicatesthe area with low
correlation in thecalculation of the source
2.5m/5m resolution DSM.
In v2.1 or later version, thevalue was filled by otherdata sets. So this mask isapplicable for v1.0 andv1.1.
*5: Based on the following
v1.0-v2.1
SWBD, GSHHG
PRISM image (Japan)
v2.2 or later
OpenStreetMap
GSI Coastline (Japan)
4.URLs 2)-5)*6: 4.URLs 6)*7: 4.URLs 7)*8: 4.URLs 8)*9: 4.URLs 9)*10: 4.URLs 10)*11: 4.URLs 11)*12: 4.URLs 12)

Mask file(MSK)[GeoTIFF format]

Details of the mask
0000 0000 (0x00): Valid
0000 0001 (0x01): Cloud and snow mask (invalid)0000 0010 (0x02): Land water and low correlation mask*4 (valid)0000 0011 (0x03): Sea mask*5 (valid)0000 0100 (0x04): GSI DTM*6 (valid)0000 1000 (0x08): SRTM-1 v3*7 (valid)0000 1100 (0x08): PRISM DSM (valid)
0001 0000 (0x10): ViewFinder Panoramas DEM*8 (valid)
0001 1000 (0x18): ASTER GDEM v2*9 (valid)
0001 1100 (0x1C): ArcticDEM v2*10 (valid)0010 0000 (0x20)：TanDEM-X 90m DEM*11 (valid)0010 0100 (0x24)：ArcticDEM v3*10 (valid)0010 1000 (0x28)：ASTER GDEM v3*9 (valid)0010 1100 (0x2C): REMA v1.1*12 (valid)
1111 1100 (0xFC): applied IDW method (gdal_fillnodata) (valid)
Stacking number
file
(STK)
[GeoTIFF format]

Headerinformation file
(HDR)
[Text format]
Quality assurance
information file
(QAI)
[Text format]
List file(LST)[Text format]

Stack number of PRISM DSM scenes used to produce source AW3D
2.5m/5m DSM
 Byte (8 bit) raster data Equirectangular projection
 Pixel spacing: basically 1 arcsec (approx. 30 m), latitude dependent STK values are average over the range of 1 arcsec grid pixel(Round off to the integer)
Meta data about the product*11
 Derived from HDR file of the source AW3D 2.5m/5m DSM*11: Table 3 for details

Quality assurance information*12
 Added the information of 30m DSM to the source AW3D 2.5m/5m
DSM*12: Table 4 for details

List of Scene IDs used to produce source AW3D 2.5m/5m DSM*13
 ID, type, orbit number, RSP path/frame, stereo mode, observationdate*13: Only v2.1 or later

3

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2.2. File naming rule
The naming rule for each file that composes AW3D30 version 3.2/3.1 dataset is as follows.
General：[Product ID]_[Tile ID]_[Kind of file].[Extention][Product ID]： ALPSMLC30 (Table 3 No.2)[Tile ID]：

Latitude/Longitude (Table 3 No.1)[Kind of file]： DSM、MSK、STK、HDR、QAI、LST (Table 1)[Extention]： tif、txt (Table 1)
Example：ALPSMLC30_N035E138_DSM.tif(DSM file)

ALPSMLC30_N035E138_MSK.tif(Mask file)

ALPSMLC30_N035E138_STK.tif(Stacking number file)

ALPSMLC30_N035E138_HDR.txt(Header information file)

ALPSMLC30_N035E138_QAI.txt(Quality assurance information file)

ALPSMLC30_N035E138_LST.txt(List file)

2.3. Latitude dependent pixel spacing
AW3D30 v3.1 uses pixel spacing for each latitude zone in order to keep the pixel spacing in the longitude
direction at approximately 30 m even in high latitude regions. Table 2 shows specific values of spacing.
AW3D30 version 3.2 are zoneⅠof Table 2 since those are low latitude region.
Table 2 AW3D30 v3.1 latitude dependent pixel spacing
Zone

Latitude range(North/South)

Pixel spacing(Latitude)

Pixel spacing(Longitude)

Data size of1ﾟx1ﾟ tileⅠ0ﾟ- 60ﾟ

1.00”

1.00”(30.922m - 15.500m)

3600 x 3600

Ⅱ

60ﾟ- 70ﾟ

1.00”

2.00”(31.000m - 21.215m)

1800 x 3600

Ⅲ

70ﾟ- 80ﾟ

1.00”

3.00”(31.822m - 16.161m)

1200 x 3600Ⅳ

80ﾟ- 90ﾟ

1.00”

6.00”(32.322m - 0.000m)

600 x 3600

4

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2.4. Header information file format
Table 3 shows the detailed items in the header information (HDR) file included in the AW3D30 dataset.
Table 3 Items in AW3D30 header information (HDR) file
Field
No.

Numberof Bytes

Description

Product Record
Product Information

Start
Byte
Position

Type

Data Identifier

Field No.1-35

Product Identifier Details

1

Tile ID = 'NNNNNNNNbbbbbbbb'
NNNNNNNN: Same as No.4

16

1

A16

2

DSM Product ID = 'AABBBCDEEbbbbbbb' (fixed)
AA :Satellite code = 'AL':ALOSBBB :Sensor code = 'PSM':PRISMC:
Grid type = 'L': Lat-Lon
D:
DSM Version = 'C':3
EE :DSM pixel spacing = '30': 30m

16

17

A16

3

Product type = 'PSM-DSMbbbbbbbbb' (fixed)

16

33

A16

4

Mesh code = 'NNNNNNNNbbbbbbbb': Geographic
coordinates at lower left corner of lower left pixel

16

49

A16

5

Satellite name = 'ALOSbbbb' (fixed)

8

65

A8

6

Sensor code = 'PSMbbbbb': PRISM (fixed)

8

73

A8

7

Coordinates = 'LTLNbbbb': Lat-Lon (fixed)

8

81

A8

8

DSM version = 'Cbbb': 3 (fixed)

4

89

A4

9

DSM grid spacing (sec) = 'b1.00bbb' (fixed)

8

93

A8

10

Blank (fixed)

28

101

A28

Subtotal
Mesh Information

NoteStandard at low-mid latitudes

128

Mesh Identifier

11

Mesh upper-left line number = 'bNNNNN.N'

8

129

F8.1

12

Mesh upper-left column number = 'bNNNNN.N'

8

137

F8.1

13

Mesh upper-right line number = 'bNNNNN.N'

8

145

F8.1

14

Mesh upper-right column number = 'bNNNNN.N'

8

153

F8.1

15

Mesh lower-left line number = 'bNNNNN.N'

8

161

F8.1

16

Mesh lower-left column number = 'bNNNNN.N'

8

169

F8.1

17

Mesh lower-right line number = 'bNNNNN.N'

8

177

F8.1

18

Mesh lower-right column number = 'bNNNNN.N'

8

185

F8.1

19

Mesh upper-left latitude (deg.)= 'NNNNNNNN.NNNNNNN' (-90.0000000 - 90.0000000)

16

193

F16.7

Negative value for southernhemisphere

20

Mesh upper-left longitude (deg.)= 'NNNNNNNN.NNNNNNN' (-180.0000000 - 180.0000000)

16

209

F16.7

Negative value for west longitude

21

Mesh upper-right latitude (deg.)= 'NNNNNNNN.NNNNNNN' (-90.0000000 - 90.0000000)

16

225

F16.7

Negative value for southernhemisphere

22

Mesh upper-right longitude (deg.)= 'NNNNNNNN.NNNNNNN' (-180.0000000 - 180.0000000)

16

241

F16.7

Negative value for west longitude

23

Mesh lower-left latitude (deg.)= 'NNNNNNNN.NNNNNNN' (-90.0000000 - 90.0000000)

16

257

F16.7

Negative value for southernhemisphere

24

Mesh lower-left longitude (deg.)= 'NNNNNNNN.NNNNNNN' (-180.0000000 - 180.0000000)

16

273

F16.7

Negative value for west longitude

25

Mesh lower-right latitude (deg.)= 'NNNNNNNN.NNNNNNN' (-90.0000000 - 90.0000000)

16

289

F16.7

Negative value for southernhemisphere

26

Mesh lower-right longitude (deg.)= 'NNNNNNNN.NNNNNNN' (-180.0000000 - 180.0000000)

16

305

F16.7

Negative value for west longitude

5

Addresses correspondence to thecorner of a pixel, not its center.
Since each pixel/line integer value
is assigned at pixel center,pixel/line number for four corners
is described with real values.

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 3 Items in AW3D30 header information (HDR) file (continued)
Field
No.

Description

Numberof Bytes

Start
Byte
PositionType

27

Mesh upper-left map address X (km)= 'NNNNNNNN.NNNNNNN'

16

321

F16.7

28

Mesh upper-left map address Y (km)= 'NNNNNNNN.NNNNNNN'

16

337

F16.7

29

Mesh upper-right map address X (km)= 'NNNNNNNN.NNNNNNN'

16

353

F16.7

30

Mesh upper-right map address Y (km)= 'NNNNNNNN.NNNNNNN'

16

369

F16.7

31

Mesh lower-left map address X (km)= 'NNNNNNNN.NNNNNNN'

16

385

F16.7

32

Mesh lower-left map address Y (km)= 'NNNNNNNN.NNNNNNN'

16

401

F16.7

33

Mesh lower-right map address X (km)= 'NNNNNNNN.NNNNNNN'

16

417

F16.7

34

Mesh lower-right map address Y (km)= 'NNNNNNNN.NNNNNNN'

16

433

F16.7

35

Blank (fixed)

16

449

A16

Subtotal
Processing Information
Map Projection

Processing Details

Field No.36-58

Map Projection Parameters

Coordinates = 'LTLNbbbb' (fixed)

8

465

A8

37

PS origin latitude (deg.) = 'NNNNNNNN.NNNNNNN'

16

473

F16.7

38

PS origin longitude (deg.) = 'NNNNNNNN.NNNNNNN'

16

489

F16.7

39

PS reference latitude (deg.) = 'NNNNNNNN.NNNNNNN'

16

505

F16.7

40

PS reference longitude/ UTM central meridian (deg.)= 'NNNNNNNN.NNNNNNN'

16

521

F16.7

41

Hemisphere = 'bbbN':North / 'bbbS':South

4

537

A4

42

UTM zone no. = 'bbb1' - 'bb60'

4

541

I4

43

Angle between vertical axis of coordinates and true northdirection (deg) = 'NNNNNNNN.NNNNNNN'

16

545

F16.7

44

Blank (fixed)

32

561

A32

Subtotal

All blank for LTLN and UTM
product

All blank for LTLN productAll blank for LTLN and PS productAt mesh centerAll blank for LTLN product

128

Datum Parameters

45

ECR coordinates = 'ITRF97bbbbbbbbbb' (fixed)

16

593

A16

46

Ellipsoid model = 'GRS80bbbbbbbbbbb' (fixed)

16

609

A16

47

Equator radius of ellipsoid model (km) ='NNNNNNNN.NNNNNNN' (fixed)

16

625

F16.7

48

Polar radius of ellipsoid model (km) ='NNNNNNNN.NNNNNNN' (fixed)

16

641

F16.7

49

Inverse flattening (1/f) of ellipsoid model ='NNNNNNNN.NNNNNNN' (fixed)

16

657

F16.7

50

Blank (fixed)

48

673

A48

Subtotal
DSM Data

All blank for LTLN product
For UTM, X in southernhemisphere includes false
northing 10,000km, and Y includes
false easting 500km

336

36

Datum

Note

128

DSM Data Parameters

51

Coordinates = 'LTLNbbbb': Lat-Lon (fixed)

8

721

A8

Same as field No.7

52

DSM type = 'Cbbb': Absolute (fixed)

4

729

A4

Same as field No.8

53

Vertical grid spacing (sec)/(m) = 'bb1.00bb' (fixed)

8

733

A8

54

Horizontal grid spacing (sec)/(m) = 'bbN.NNbb'

8

741

A8

Second for LTLN
Meter for UTM and PS

6

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 3 Items in AW3D30 header information (HDR) file (continued)
Field
No.

Description

Numberof Bytes

Start
Byte
Position

Type

55

Height resolution of DSM (m) = '1bbbbbbb' (fixed)

8

749

I8

56

Height type = 'Obbb': Orthometric Height (fixed)

4

757

A4

57

Geoid data = 'XXXXXXXXXXXXXXXX''GSI-2000bbbbbbbb': Japan Geoid 2000
'NGA-EGM96bbbbbbb': EGM96

16

761

A16

58

Blank (fixed)

8

777

A8

Subtotal
Quality Record

Field No.59-64

59

Mask (00000000) (%) = 'bNNN'

4

785

I4

60

Mask (00000001) (%) = 'bNNN'

4

789

I4

61

Mask (00000010) (%) = 'bNNN'

4

793

I4

62

Mask (00000011) (%) = 'bNNN'

4

797

I4

63

DSM data quality (Rate of valid pixels) = 'bbbX''G': Good = 100 - 81 %'F': Fair = 80 - 51 %'P': Poor = 50 - 0 %

4

801

A4

64

Blank (fixed)

44

805

A44

Format Record

Data Format Information

Field No.65-82

Header record length (byte) = 'bbbbNNNN'

8

849

I8

66

Data column length (number of pixels for each line) ='bbbNNNNN' (fixed)

8

857

I8

67

Data line length (number of pixels for each column) ='bbbNNNNN' (fixed)

8

865

I8

68

Byte order = 'LSBbbbbb':Little endian (fixed)

8

873

A8

Subtotal

32

DSM Data Format Structures

69

Number of bits for DSM 1 pixel (bit) = 'bb16' (fixed)

4

881

I4

70

Number of pixels for DSM 1 data (pixel) = 'bbb1' (fixed)

4

885

I4

71

Number of bytes for DSM 1 data (byte) = 'bbb2' (fixed)

4

889

I4

72

Bit start for DSM 1 pixel (bit) = 'bbb0' (fixed)

4

893

I4

73

Bit end for DSM 1 pixel (bit) = 'bb15' (fixed)

4

897

I4

74

Number of DSM files = 'bbb1' (fixed)

4

901

I4

75

Blank (fixed)

8

905

A8

Subtotal
MSK Data Format

Right-aligned

64

65

DSM Data Format

All blank for height type 'E'(Ellipsoid height)

64

Quality Information from the 5m DSM

Subtotal

Note

32

MSK Data Format Structures

76

Number of bits for MSK 1 pixel (bit) = 'bbb8' (fixed)

4

913

I4

77

Number of pixels for MSK 1 data (pixel) = 'bbb1' (fixed)

4

917

I4

78

Number of bytes for MSK 1 data (byte) = 'bbb1' (fixed)

4

921

I4

7

Variable header file size

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 3 Items in AW3D30 header information (HDR) file (continued)
Field
No.

Description

Numberof Bytes

Start
Byte
PositionType

79

Bit start for MSK 1 pixel (bit) = 'bbb0' (fixed)

4

925

I4

80

Bit end for MSK 1 pixel (bit) = 'bbb7' (fixed)

4

929

I4

81

Number of MSK files = 'bbb1' (fixed)

4

933

I4

82

Blank (fixed)

40

937

A40

Subtotal
System Record

Note

64

Data Processing System Information

Field No.83-90

83

Processing date (JST) = 'YYYYMMDDbbbbbbbb'
YYYY: YearMM: Month
DD
: Day

16

977

A16

Processing date of source AW3D

84

Processing time (JST) = 'HHMMSSbbbbbbbbbb'
HH: HourMM: Minute
SS: Second

16

993

A16

Processing date of source AW3D

85

Processing country = 'JAPANbbbbbbbbbbb' (fixed)

16

1009

A16

86

Processing organization = 'JAXAbbbbbbbbbbbb' (fixed)

16

1025

A16

87

Processing facility = 'EORC-AGAPbbbbbbb' (fixed)

16

1041

A16

88

Software version = 'VVV-RRR-YYYYMMDDbbbbbbbb'
VVV: Version No.
RRR: Release No.
YYYY: Release year
MM
: Release monthDD: Release date

24

1057

A24

89

Document version = 'N.Nb'

4

1081

A4

90

Blank (fixed)

20

1085

A20

1105

I4

Subtotal

128

Reserved
91

Version of base document

Field No.91

Blank (fixed)

4
Subtotal
Total

8

4
1108

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2.5. Quality assurance information file format
Detailed items in the quality assurance information (QAI) file included in the AW3D30 dataset aresummarized in Table 4. First half of the items are the quality assurance information obtained from the source
AW3D 2.5m/5m DSM dataset that is the origin of AW3D30 30m DSM. Table 5 shows criteria for comprehensive
evaluation.
Table 4 Items in AW3D30 quality assurance information (QAI) file
Category

Item

Key
TOTAL_ACCURACYG

TOTAL_INTEGRITY

G

Comprehensive assessment: reliability

TOTAL_RELIABILITY

G

Average of difference: SRTM

SRTM_AVERAGE

1.9333076

Standard deviation of difference: SRTM

SRTM_STDEV

8.6490392

RMS of difference: SRTM

SRTM_RMS

8.47604

Maximum of difference: SRTM

SRTM_MAX

68.509979

Mode of difference: SRTM

SRTM_MODE

Average of difference: ASTER GDEM

ASTER_AVERAGE-0.55988584

Standard deviation of difference: ASTER GDEM

ASTER_STDEV

14.906643

RMS of difference: ASTER GDEM

ASTER_RMS

14.5537

Maximum of difference: ASTER GDEM

ASTER_MAX

141.71265

Mode of difference: ASTER GDEM

ASTER_MODE

0

Number of comparison points with ICESat

ICESAT_NUM

53

Average of difference: ICESat

ICESAT_AVERAGE

0.470889

Standard deviation of difference: ICESat

ICESAT_STDEV

3.57531ICESAT_RMS

3.57259

ICESAT_MAX

14.0139

Comprehensive assessment: accuracy*1*1Comprehensive assessment: completeness*1

Source2.5m DSM
4 tiles(Japan)Value(sample)RMS of difference: ICESat
SourceMaximum of difference: ICESat
5m DSM
Mode of difference: ICESat
1 tile(except Japan) Average of relative error between stacked images

ICESAT_MODE

30

REL_STACK_AVERAGE

2.18556

Standard deviation of relative error between stacked images

REL_STACK_STDEV

1.13929

Number of valid pixel

MASK_NUM_VALID

574972351

Number of cloud and snow masked pixel

MASK_NUM_CLOUDSNOW

2360

Number of inland water and low correlation masked pixels MASK_NUM_INLANDWATER

831055

Number of sea masked pixels

MASK_NUM_SEA

194234Rate of valid pixel

MASK_RATE_VALID

0.998216

Rate of cloud and snow masked pixels

MASK_RATE_CLOUDSNOW

0.0000041

Rate of inland water and low correlation masked pixels

MASK_RATE_INLANDWATER

0.0014428

Rate of sea masked pixels

MASK_RATE_SEA

0.000337212

Correlation coefficient: average

CORREL_AVERAGE

0.635053

Correlation coefficient: standard deviation

CORREL_STDEV

0.251597

Correlation coefficient: maximum

CORREL_MAX

1

Correlation coefficient: minimum

CORREL_MIN-1

9

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 4 Items in AW3D30 quality assurance information (QAI) file (continued)
Category

Item

Key

Value
(sample)Correlation coefficient histogram: from -1.0 to -0.9

CORREL_HIST_-1.0to-0.9

2215

Correlation coefficient histogram: from -0.9 to -0.8

CORREL_HIST_-0.9to-0.8

0Correlation coefficient histogram: from -0.8 to -0.7

CORREL_HIST_-0.8to-0.7

3Correlation coefficient histogram: from -0.7 to -0.6

CORREL_HIST_-0.7to-0.6

7Correlation coefficient histogram: from -0.6 to -0.5

CORREL_HIST_-0.6to-0.5

41Correlation coefficient histogram: from -0.5 to -0.4

CORREL_HIST_-0.5to-0.4

261

Correlation coefficient histogram: from -0.4 to -0.3

CORREL_HIST_-0.4to-0.3

1518

Correlation coefficient histogram: from -0.3 to -0.2

CORREL_HIST_-0.3to-0.2

6901

Correlation coefficient histogram: from -0.2 to -0.1

CORREL_HIST_-0.2to-0.1

36766

Correlation coefficient histogram: from -0.1 to 0.0

CORREL_HIST_-0.1to0.0

212610

Correlation coefficient histogram: from 0.0 to 0.1

CORREL_HIST_0.0to0.1

919562

Correlation coefficient histogram: from 0.1 to 0.2

CORREL_HIST_0.1to0.2

3565829

Correlation coefficient histogram: from 0.2 to 0.3
Source5m DSM
Correlation coefficient histogram: from 0.3 to 0.4
1 tileCorrelation coefficient histogram: from 0.4 to 0.5(except Japan)
Correlation coefficient histogram: from 0.5 to .0.6

CORREL_HIST_0.2to0.3

12236681

CORREL_HIST_0.3to0.4

33412879

CORREL_HIST_0.4to0.5

70300296

CORREL_HIST_0.5to0.6

111074518

Correlation coefficient histogram: from 0.6 to 0.7

CORREL_HIST_0.6to0.7

132675287

Correlation coefficient histogram: from 0.7 to 0.8

CORREL_HIST_0.7to0.8

122173898

Correlation coefficient histogram: from 0.8 to 0.9

CORREL_HIST_0.8to0.9

75815662

Correlation coefficient histogram: from 0.9 to 1.0

CORREL_HIST_0.9to1.0

12537417

Number of stacking: average

STACK_AVERAGE

4.76069

Number of stacking: standard deviation

STACK_STDEV

1.91647

Number of stacking: Minimum

STACK_MIN

0

Number of stacking: Maximum

STACK_MAX

14

Number of valid pixel

AW3Dv3.1_MASK_NUM_VALID

Number of cloud and snow mask pixel

AW3Dv3.1_MASK_NUM_CLOUDSNOW

2595589

Number of inland water and low correlation mask pixels

AW3Dv3.1_MASK_NUM_INLANDWATER

0

Number of sea mask pixels

AW3Dv3.1_MASK_NUM_SEA

22420287

Rate of valid pixel

AW3Dv3.1_MASK_RATE_VALID

95.65696597

Rate of cloud and snow mask pixels

AW3Dv3.1_MASK_RATE_CLOUDSNOW

0.45062309

Rate of inland water and low correlation mask pixels

AW3Dv3.1_MASK_RATE_INLANDWATER

0

Rate of sea mask pixels

AW3Dv3.1_MASK_RATE_SEA

Number of valid pixel

DegradeAVE_MASK_NUM_VALID

Number of cloud and snow mask pixel

DegradeAVE_MASK_NUM_CLOUDSNOW

46079

Number of inland water and low correlation mask pixels

DegradeAVE_MASK_NUM_INLANDWATER

0

Number of sea mask pixels

DegradeAVE_MASK_NUM_SEA

Rate of valid pixel

DegradeAVE_MASK_RATE_VALID

95.7739892

Rate of cloud and snow mask pixels

DegradeAVE_MASK_RATE_CLOUDSNOW

0.35554784

Rate of inland water and low correlation mask pixels

DegradeAVE_MASK_RATE_INLANDWATER

0

Rate of sea mask pixels

DegradeAVE_MASK_RATE_SEA

Source2.5m DSM
4 tiles(Japan)Intermediate
5m DSMmask
information(Japan)Intermediate
30m DSMmask
information

10550984124

3.892410938
12412309

5016123.870462963

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 4 Items in AW3D30 quality assurance information (QAI) file (continued)
Category

Product
30m DSMmask
information

Item

Key

Value
(sample)Number of cloud and snow mask pixel (after void-filling)

GapFillAVE_MASK_NUM_CLOUDSNOW

0

Number of pixels filled with GSI 10m DEM

GapFillAVE_MASK_NUM_FILLED_GSI10

26019

Number of pixels filled with SRTM-1 Version 3

GapFillAVE_MASK_NUM_FILLED_SRTM-1_V3

Number of pixels filled with PRISM DSM

GapFillAVE_MASK_NUM_FILLED_PSM

Number of pixels filled with ArcticDEM v3

GapFillAVE_MASK_NUM_FILLED_ArcticDEM_v30

Number of pixels filled with ArcticDEM v2

GapFillAVE_MASK_NUM_FILLED_ArcticDEM_v20

Number of pixels filled with ASTER GDEM v3

GapFillAVE_MASK_NUM_FILLED_GDEM_v30

Number of pixels filled with TanDEM-X 90m DEM

GapFillAVE_MASK_NUM_FILLED_WorldDEM_v3

0

0
20060

Number of pixels filled with Viewfinder Panoramas DEM
GapFillAVE_MASK_NUM_FILLED_VPD(Only for version 3.2)0

Number of pixels filled with REMA v1.1
(Only for version 3.1 South of 60 degrees South)

GapFillAVE_MASK_NUM_FILLED_REMA_v1.1

0

Number of pixels filled with IDW method

GapFillAVE_MASK_NUM_FILLED_FillNoData

0

Rate of cloud and snow mask pixel (after void-filling)

GapFillAVE_MASK_RATE_CLOUDSNOW0Rate of pixels filled with GSI 10m DEM

GapFillAVE_MASK_RATE_FILLED_GSI10

0.200763889

Rate of pixels filled with SRTM1 Version 3

GapFillAVE_MASK_RATE_FILLED_SRTM-1_V3

Rate of pixels filled with PRISM DSM

GapFillAVE_MASK_RATE_FILLED_PSM

Rate of pixels filled with ArcticDEM v3

GapFillAVE_MASK_RATE_FILLED_ArcticDEM_v3

0

Rate of pixels filled with ArcticDEM v2

GapFillAVE_MASK_RATE_FILLED_ ArcticDEM_v2

0

Rate of pixels filled with ASTER GDEM v3

GapFillAVE_MASK_RATE_FILLED_GDEM_v3

0

Rate of pixels filled with TanDEM-X 90m DEM

GapFillAVE_MASK_RATE_FILLED_WorldDEM_v3

000.154783951

Rate of pixels filled with Viewfinder Panoramas DEM
GapFillAVE_MASK_RATE_FILLED_VPD(Only for version 3.2)0Rate of pixels filled with REMA v1.1
(Only for version 3.1 South of 60 degrees South)

GapFillAVE_MASK_RATE_FILLED_REMA_v1.1

0

Rate of pixels filled with IDW method

GapFillAVE_MASK_RATE_FILLED_FillNoData0

Void-filled product Version of void-filled product

VERSION_GapFill_PRODUCT

3.1

Source product Version of source product

VERSION_AW3D_PRODUCT

3*1: Evaluation items and strategies in comprehensive assessment are as follows.
1) Comprehensive assessment - accuracy: statistical evaluation on the absolute difference from existing global topographic data such as
SRTM-3, ASTER GDEM, and ICESat
2) Comprehensive assessment - completeness: evaluation on the area occupancy of cloud and snow mask and land water and low correlation
mask to land areas
3) Comprehensive assessment - reliability: statistical evaluation on the histograms of correlation coefficients in stereo-pair matching and on
stacking number
Table 5 shows the criteria for comprehensive evaluation*2: Descriptions of source products are applicable for v2.1 or later ('-' indicates the tile was not made from AW3D)

Table 5 Criteria for comprehensive evaluation in QAI file
Item

Good

Fair

Poor

Accuracy

＜5m

＜7m

≧7m

Completeness

≧90%

≧70%

＜70%

Reliability

≧1.5

≧1.0

＜1.0

11

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2.6. TIFF tag settings for GeoTIFF product
Tables 6 to 8 summarize the TIFF tag settings for GeoTIFF product (DSM file, mask file and stacking number
file) included in AW3D30 dataset.
Table 6 TIFF tag settings for GeoTIFF product (DSM file)
Value(Sample)

Tag

ID

Type

Number

NewSubfileType

254

Long

1

0

ImageWidth

256

Short

1

3600

ImageLength

257

Short

1

3600

BitsPerSample

258

Short

1

16

Compression

259

Short

1

1 (No compression)

PhotometricInterpretation

262

Short

1

1 (Black is zero)

ImageDescription

270

Ascii

20

Product Version 3.2 (Tag for version 3.2 only)

StripOffsets

273

Long

3600

14408 21608 28808 36008 43208 50408 …

Orientation

274

Short

1

1

SamplesPerPixel

277

Short

1

1

RowsPerStrip

278

Short

1

1

StripByteCounts

279

Long

3600

XResolution

282

Rational1

1/1

YRresolution

283

Rational

1

1/1

PlanarConfiguration

284

Short

1

1 (Chunky format)

SampleFormat

339

Short

1

2 (Signed integer)

ModelPixelScale

33550

Double30.000278 0.000278 0.000000

ModelTiepoint

33922

Double60.000000 0.000000 0.000000
138.000000 35.000000 0.000000

GeoKeyDirectory

34735

Short

24

1 1 0 5 1024 0 1 2 1025 0 1 1 2048 0 1 4326
2052 0 1 9001 2054 0 1 9102

GeoAsciiParams

34737

Ascii

7

WGS 84127200 7200 7200 7200 7200 7200 …

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

Table 7 TIFF tag settings for GeoTIFF product (MSK files)
Tag

Value
(Sample)ID

Type

NumberImageWidth

256

Short

1

3600

ImageLength

257

Short

1

3600

BitsPerSample

258

Short

1

8

Compression

259

Short

1

1 (No compression)

PhotometricInterpretation

262

Short

1

1 (Black is zero)

ImageDescription

270

Ascii

20

Product Version 3.2 (Tag for version 3.2 only)

StripOffsets

273

Long

1800

192378 216378 240378 264378 288378 312378 …

SamplesPerPixel

277

Short

1

1

RowsPerStrip

278

Short

1

2

StripByteCounts

279

Long

1800

PlanarConfiguration

284

Short

1

1 (Chunky format)

SampleFormat

339

Short

1

1 (Chunky format)

ModelPixelScale

33550

Double30.000278 0.000278 0.000000

ModelTiepoint

33922

Double60.000000 0.000000 0.000000
138.000000 35.000000 0.000000

GeoKeyDirectory

34735

Short

32

1 1 0 7 1024 0 1 2 1025 0 1 1 2048 0 1 4326
2049 34737 7 0 2054 0 1 9102 2057 34736 1 12059 34736 1 0

GeoDoubleParams

34736

Double2298.257224 6378137.000000

GeoAsciiParams

34737

Ascii

8

WGS 84|

GDAL_NODATA

42113

Ascii

7

255

7200 7200 7200 7200 7200 7200 …

Table 8 TIFF tag settings for GeoTIFF product (STK file)
Value(Sample)

Tag

ID

Type

Number

NewSubfileType

254

Long

1

0

ImageWidth

256

Short

1

3600

ImageLength

257

Short

1

3600

BitsPerSample

258

Short

1

8

Compression

259

Short

1

1 (No compression)

PhotometricInterpretation

262

Short

1

1 (Black is zero)

ImageDescription

270

Ascii

20

Product Version 3.2 (Tag for version 3.2 only)

StripOffsets

273

Long

3600

14408 18008 21608 25208 28808 32408 …

Orientation

274

Short

1

1

SamplesPerPixel

277

Short

1

1

RowsPerStrip

278

Short

1

1

StripByteCounts

279

Long

3600

XResolution

282

Rational1

1/1

YRresolution

283

Rational

1

1/1

PlanarConfiguration

284

Short

1

1 (Chunky format)

ModelPixelScale

33550

Double30.000042 0.000042 0.000000

ModelTiepoint

33922

Double60.000000 0.000000 0.000000
138.000000 35.000000 0.000000

GeoKeyDirectory

34735

Short

24

1 1 0 5 1024 0 1 2 1025 0 1 1 2048 0 1 4326
2052 0 1 9001 2054 0 1 9102

GeoAsciiParams

34737

Ascii

7

WGS84

13

3600 3600 3600 3600 3600 3600 …

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

2.7. GeoTIFF key settings for GeoTIFF product
Table 9 to 11 show the Geo key settings for GeoTIFF product (DSM file, mask file and stacking number file)included in AW3D30 dataset.

Table 9Key

Geo key settings for GeoTIFF product(DSM file)
Value(Sample)ID

Type

NumberGTModelTypeGeoKey

1024

Short

1

2 (ModelTypeGeographic)

GTRasterTypeGeoKey

1025

Short

1

1 (RasterPixelIsArea)

GeographicTypeGeoKey

2048

Short

1

4326 (GCS_WGS_84)

GeogLinearUnitsGeoKey

2053

Short

1

9001 (Linear_Meter)

GeogAngularUnitsGeoKey

2054

Short

1

9102 (Angular_Degree)

Table 10
Key

Geo key settings for GeoTIFF product(MSK file)
Value(Sample)ID

Type

NumberGTModelTypeGeoKey

1024

Short

1

2 (ModelTypeGeographic)

GTRasterTypeGeoKey

1025

Short

1

1 (RasterPixelIsArea)

GeographicTypeGeoKey

2048

Short

1

4326 (GCS_WGS_84)

GeogCitationGeoKey

2049

Ascii

7

WGS 84

GeogAngularUnitsGeoKey

2054

Short

1

9102 (Angular_Degree)

GeogSemiMajorAxisGeoKey

2057

Double16378137

GeogInvFlatteningGeoKey

2059

Double1298.257224

Table 11
Key

Geo key settings for GeoTIFF product(STK file)
Value(Sample)ID

Type

NumberGTModelTypeGeoKey

1024

Short

1

2 (ModelTypeGeographic)

GTRasterTypeGeoKey

1025

Short

1

1 (RasterPixelIsArea)

GeographicTypeGeoKey

2048

Short

1

4326 (GCS_WGS_84)

GeogLinearUnitsGeoKey

2053

Short

1

9001 (Linear_Meter)

GeogAngularUnitsGeoKey

2054

Short

1

9102 (Angular_Degree)

14

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

3. References
1) T. Tadono, H. Ishida, F. Oda, S. Naito, K. Minakawa, and H. Iwamoto, “Precise Global DEM Generation
by ALOS PRISM,” ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information
Sciences, Vol.II-4, pp.71-76, 2014.
2) J. Takaku, T. Tadono, and K. Tsutsui, “Generation of High Resolution Global DSM from ALOS PRISM,”
The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences,
ISPRS, Vol.XL-4, pp.243-248, 2014.
3) J. Takaku, T. Tadono, K. Tsutsui, and M. Ichikawa, "Validation of 'AW3D' Global DSM Generated fromALOS PRISM," ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences,
Vol.III-4, pp. 25-31, 2016.
4) T. Tadono, H. Nagai, H. Ishida, F. Oda, S. Naito, K. Minakawa, and H. Iwamoto, “Initial Validation of the
30 m-mesh Global Digital Surface Model Generated by ALOS PRISM, The International Archives of the
Photogrammetry, Remote Sensing and Spatial Information Sciences, ISPRS, Vol.XLI-B4, pp.157-162,
2016.
5) G. Grohman, G. Kroenung, and J. Strebeck, "Filling SRTM Voids: The Delta Surface Fill Method,"
Photogrammetric Engineering & Remote Sensing, Vol.72, No.3, pp.213-216, 2016.
6) J. Takaku and T. Tadono, “Quality updates of ‘AW3D’ global DSM generated from ALOS PRISM,” Proc.
IGARSS2017, IEEE, Fort Worth, TX, USA., pp. 5666-5669, 2017.
7) J. Takaku, T. Tadono, K. Tsutsui, and M. Ichikawa, ”Quality Improvements of ‘AW3D’ Global DSM Derived
from ALOS PRISM”, Proc. IGARSS2018, IEEE, Valencia, Spain, pp. 1612-1615, 2018.

15

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

4. Related URLs
1) EGM96 (NGA/NASA)https://cddis.nasa.gov/926/egm96/egm96.html
2) SWBD (NASA/JPL)
https://dds.cr.usgs.gov/srtm/version2_1/SWBD/
3) GSHHG (former GSHHS) (University of Hawaii/NOAA)
https://www.soest.hawaii.edu/pwessel/gshhs/index.html
4) OpenStreetMap Coastlines (Jochen Topf & Christoph Hormann)
https://osmdata.openstreetmap.de/data/coastlines.html
5) GSI Coastline Vector Data*1
https://fgd.gsi.go.jp/download/ref_kihon.html *Only in Japanese
6) GSI Digital Topographic Map 5m and 10m Mesh Data*1
https://fgd.gsi.go.jp/download/ref_dem.html *Only in Japanese
7) SRTM-1 v3 (NASA/JPL)
https://www2.jpl.nasa.gov/srtm/
8) Viewfinder Panoramas DEM （Jonathan de Ferranti）
http://viewfinderpanoramas.org/dem3.html
9) ArcticDEM v2, v3 (NGA/NSF)
https://www.pgc.umn.edu/data/arcticdem
10) ASTER GDEM v2, v3 (NASA/METI)
https://asterweb.jpl.nasa.gov/gdem.asp
11) TanDEM-X 90m DEM （DLR）
https://geoservice.dlr.de/web/dataguide/tdm90/
12) REMA v1.1 （PGC, University of Minnesota）
https://www.pgc.umn.edu/data/rema/*1： Approved by the GSI based on Survey Act (Utilization) R 1JHs 1312

16

ALOS Global Digital Surface Model (DSM) “ALOS World 3D-30m” (AW3D30) Ver.3.2/3.1
Product Description

5. Point of contact
Please contact to the ALOS Science Project via e-mail to the address below for any questions or inquiries
regarding the use of the dataset. For our future reference, it is highly appreciated sending the offprints andcopies of the research results using the dataset to the following point of contact.
ALOS Science Project
Earth Observation Research Center (EORC)
Japan Aerospace Exploration Agency (JAXA)
E-mail: aproject@jaxa.jp

17