Short Citation:
Pacific Islands Fisheries Science Center, 2019: Satellite-derived bathymetry for nearshore benthic habitats in Timor-Leste, https://inport.nmfs.noaa.gov/inport/item/46150.

Item Identification

Title: Satellite-derived bathymetry for nearshore benthic habitats in Timor-Leste
Short Name: Timor: WV-2 Bathymetry
Status: Completed
Publication Date: 2017
Abstract:

Bathymetric data derived from multispectral, high-resolution (2 m) satellite imagery from DigitalGlobe’s WorldView-2 satellite to provide near complete coverage of nearshore terrain along the northern coastline of Timor-Leste, including the district of Oecusse to the west of mainland Timor-Leste and Atauro Island. Satellite images acquired by the NOAA Coral Reef Ecosystem Program (CREP) for the region are from Feb 9, 2010 to October 2, 2013. Methods used by CREP to estimate depths from the WorldView imagery were adapted from instructions developed by Kyle Hogrefe for using IKONOS imagery to derive seafloor elevations in optically clear water (Ehses and Rooney 2015).

Bathymetry values shallower than ~20 m were derived by gauging the relative attenuation of coastal, blue, green and yellow spectral radiance as a function of depth. A multiple linear regression analysis of coastal, blue, green and yellow band spectral values against in-situ depth determined the variables of y-intercept, coastal, blue, green and yellow slope values. The variables for each band were then used in a multivariate slope intercept equation to derive depth over the imagery. Variables and combinations of the bands were adjusted to improve the statistical accuracy and spatial coverage of the final derived bathymetry product. Digital image processing to derive depths was conducted with ENVI, and editing and integration was performed using Esri's ArcGIS.

The method assumes uniform water clarity but deviations from that condition made extraction difficult in water depths greater than 20 m. Results show that biotic material, or sediment in the water column skewed results shallower if the material has a high albedo and deeper if the material has a low albedo.

Purpose:

In 2011, NOAA and the United States Agency for International Development (USAID) Timor-Leste Mission formed a 5-year bi-lateral partnership agreement from 2012 to 2016, in support of the Government of Timor-Leste—particularly the Ministry of Agriculture and Fisheries (MAF)—by addressing significant information gaps in their nearshore marine ecosystems. Specifically, MAF asked NOAA to address the following questions:

1. Where are the nearshore marine resources?

2. What are the nearshore marine resources?

3. How are they changing over time and what threats are potentially causing these changes?

4. What approaches are needed to manage and conserve the nearshore marine resources?

With financial support from USAID and in-kind support from the NOAA Coral Reef Conservation Program (CRCP), the NOAA Coral Reef Ecosystem Program (NOAA-CREP) conducted baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste. The primary activities conducted by NOAA to answer these questions included:

1. satellite mapping of nearshore habitats,

2. conducting coral reef ecosystem assessments,

3. establishing ecological baselines for climate change, and

4. building management capacity by developing a spatial data framework

The bathymetry data described herein resulted from the first activity to conduct satellite mapping for the nearshore waters around Timor-Leste.

Other Citation Details:

Pacific Islands Fisheries Science Center. 2017. Interdisciplinary baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste: Final Report. Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-17-002, 234 p. https://doi.org/10.7289/V5/SP-PIFSC-17-002.

Supplemental Information:

The method to derive depths from WorldView-2 satellite imagery is documented in the following NOAA publication:

Ehses, J. S., and J. J. Rooney. 2015. Depth derivation using multispectral WorldView-2 satellite imagery. U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-46, 24 p. doi:10.7289/V5668B40

Keywords

Theme Keywords

Thesaurus Keyword
CoRIS Discovery Thesaurus Geographic Information > Bathymetry
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Aquatic Habitat > Benthic Habitat
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Aquatic Habitat > Coastal Habitat
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Aquatic Habitat > Reef Habitat
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > GIS
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Mapping > Base map
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Remote Sensing
CoRIS Theme Thesaurus EARTH SCIENCE > Biosphere > Zoology > Corals > Reef Monitoring and Assessment > Remote Sensing > Satellite (digital scans) > WorldView-2
CoRIS Theme Thesaurus EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Bathymetry
CoRIS Theme Thesaurus EARTH SCIENCE > Oceans > Bathymetry/Seafloor Topography > Water Depth
CoRIS Theme Thesaurus EARTH SCIENCE > Oceans > Coastal Processes > Coral Reefs
ISO 19115 Topic Category 006
ISO 19115 Topic Category elevation
NODC DATA TYPES THESAURUS BATHYMETRY
NODC DATA TYPES THESAURUS water depth
NODC OBSERVATION TYPES THESAURUS derived products
NODC OBSERVATION TYPES THESAURUS GIS product
NODC PROJECT NAMES THESAURUS CORAL REEF STUDIES
NODC PROJECT NAMES THESAURUS Coral Triangle Initiative
NODC SUBMITTING INSTITUTION NAMES THESAURUS US DOC; NOAA; NMFS; Pacific Islands Fisheries Science Center; Ecosystem Sciences Division; Coral Reef Ecosystem Program
None Coral Reef Ecosystem Division
None Coral Reef Ecosystem Program
None CRED
None CREP
None derived depths
None estimated depths
None Pacific Islands Fisheries Science Center
None PIFSC
None Pseudobathymetry
None seafloor elevation
None United States Agency for International Development
None USAID

Spatial Keywords

Thesaurus Keyword
CoRIS Place Thesaurus COUNTRY/TERRITORY > Democratic Republic of Timor-Leste (East Timor) (09S126E0001)
CoRIS Place Thesaurus OCEAN BASIN > Indian Ocean > Timor Sea > Democratic Republic of Timor-Leste (East Timor) (09S126E0001)
NODC SEA AREA NAMES THESAURUS Indian Ocean
NODC SEA AREA NAMES THESAURUS Timor Sea
None Atauro
None Baucau
None Bobonaro
None Dili
None Jaco
None Lautem
None Liquica
None Manatuto
None Oecusse
None Timor
None Timor-leste
None Vila MPA

Stratum Keywords

Thesaurus Keyword
Global Change Master Directory SEA FLOOR

Physical Location

Organization: Pacific Islands Fisheries Science Center
City: Honolulu
State/Province: HI
Country: USA

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: GIS dataset of raster files
Maintenance Frequency: None Planned
Data Presentation Form: Map (digital)
Entity Attribute Overview:

Bathymetry raster files, in geotiff format, derived from WorldView-2 satellite imagery from coastal waters of Timor-Leste. Pixel values reflect the estimated depth in meters.

Distribution Liability:

While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Data Set Credit: PIFSC Coral Reef Ecosystem Program and funded by the United States Agency for International Development

Support Roles

Data Steward

CC ID: 703739
Date Effective From: 2012
Date Effective To:
Contact (Person): Acoba, Tomoko S
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Email Address: tomoko.acoba@noaa.gov
Phone: (808)725-5448
Business Hours: 8:00 am - 4:00 pm HST
Contact Instructions:

email preferred

Distributor

CC ID: 703740
Date Effective From: 2017
Date Effective To:
Contact (Organization): National Centers For Environmental Information (Boulder) (NCEI-Boulder)
Address: E/GC 325 Broadway
Boulder, CO 80305-3328
Phone: 303-497-6826
URL: https://www.ngdc.noaa.gov/

Distributor

CC ID: 747178
Date Effective From: 2015
Date Effective To:
Contact (Organization): Pacific Islands Fisheries Science Center (PIFSC)
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Phone: 808-725-5300
URL: http://www.pifsc.noaa.gov
Business Hours: 8:00 a.m. - 4:30 p.m.

Distributor

CC ID: 703741
Date Effective From: 2012
Date Effective To: 2017
Contact (Person): DesRochers, Annette M
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Email Address: annette.desrochers@noaa.gov
Phone: (808)725-5461
Business Hours: 8 am - 5 pm
Contact Instructions:

email preferred

Metadata Contact

CC ID: 703742
Date Effective From: 2012
Date Effective To:
Contact (Person): DesRochers, Annette M
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Email Address: annette.desrochers@noaa.gov
Phone: (808)725-5461
Business Hours: 8 am - 5 pm
Contact Instructions:

email preferred

Originator

CC ID: 703743
Date Effective From: 2012
Date Effective To:
Contact (Organization): Pacific Islands Fisheries Science Center (PIFSC)
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Phone: 808-725-5300
URL: http://www.pifsc.noaa.gov
Business Hours: 8:00 a.m. - 4:30 p.m.

Point of Contact

CC ID: 703744
Date Effective From: 2012
Date Effective To:
Contact (Person): DesRochers, Annette M
Address: 1845 Wasp Blvd.
Honolulu, HI 96818
USA
Email Address: annette.desrochers@noaa.gov
Phone: (808)725-5461
Business Hours: 8 am - 5 pm
Contact Instructions:

email preferred

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Description:

Timor-Leste

Extent Group 1 / Geographic Area 1

CC ID: 703746
W° Bound: 124
E° Bound: 127.4
N° Bound: -8.1
S° Bound: -9.4
Description

The northern coastline of mainland Timor-leste, as well as the coastlines of Oecusse district and Atauro Island.

Extent Group 1 / Time Frame 1

CC ID: 703747
Time Frame Type: Range
Start: 2010-02-09
End: 2013-10-02
Description:

Time span of satellite images acquired from DigitalGlobe, Inc. used for deriving bathymetry

Access Information

Security Class: Unclassified
Security Classification System:

Not applicable

Security Handling Description:

Not applicable

Data Access Policy:

NOAA Coral Reef Ecosystem Program (CREP) Data Sharing Recommendations, version 9.0 updated August 12, 2015:

CREP welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. CREP has a very diverse set of field activities that generates large volumes of data using an array of data collection protocols.

The following recommendations are for your consideration as you use this data:

1) Data analyses should take all field exigencies into account. The most effective way to do this would be active collaboration with CREP principal investigators.

2) In all presentations, product releases, or publications using data generated by CREP, proper acknowledgement of both CREP and the individuals responsible for data collection is expected. Citing the DOI (if available) is preferred, a non-DOI example is listed below.

3) If you collect or generate data for the same study areas, CREP requests that you share relevant information on complimentary data collections.

4) Those receiving data are strongly urged to inform the CREP Data Management Team of any errors and discrepancies that are discovered during the course of using these data. They are further urged to bring to the attention of the Team all problems and difficulties encountered in using these data. This information is necessary in order to improve the collections and to facilitate more efficient and economical data processing and retrieval. The users are asked to supply copies of any missing data that may be located, and to provide information as to significant subsets and special aggregations of data that are developed in using the material provided.

Example citation:

"This publication makes use of data products provided by the Coral Reef Ecosystem Program (CREP), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), with funding support from the United States Agency for International Development (USAID). The analysis and interpretations presented here are solely that of the current authors.”

Data Access Procedure:

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive

Data Access Constraints:

None

Data Use Constraints:

Please cite NOAA Coral Reef Ecosystem Program (CREP) when using the data.

Example

Coral Reef Ecosystem Program; Pacific Islands Fisheries Science Center (2017). Satellite-derived bathymetry for nearshore benthic habitats in Timor-Leste. NOAA's National Centers for Environmental Information. Dataset. https://inport.nmfs.noaa.gov/inport/item/46150

Metadata Access Constraints:

None

Metadata Use Constraints:

None

Distribution Information

Distribution 1

CC ID: 569159
Download URL: http://accession.nodc.noaa.gov/0169504
Distributor: National Centers For Environmental Information (Boulder) (NCEI-Boulder) (2017 - Present)
File Name: Bathymetry_Timor.zip
Description:

GeoTiff raster bathymetry data for nearshore waters of Timor Leste, derived from WorldView-2 satellite imagery. The bathymetry data are organized by region (north shore, Atauro Island, and Oecusse), and each region contains 1) the individual final bathymetry files (one geoTiff for each satellite image), 2) a projected (UTM_Zone_51S) bathymetry mosaic for the region, and 3) an unprojected (WGS84) mosaic for the region. The mosaics are also in geoTiff format. An ESRI layer file is included within each region's subfolder for ease of displaying the geoTiffs in ESRI's ArcGIS software. The symbology is based on the VALUE field.

File Date/Time: 2017-06-14 00:00:00
File Type: GeoTIFF

Distribution 2

CC ID: 569161
Download URL: http://accession.nodc.noaa.gov/0169504
Distributor: National Centers For Environmental Information (Boulder) (NCEI-Boulder) (2017 - Present)
File Name: README.ZIP
Description:

README folder contains the README.txt files for each final bathymetry geoTiff produced for the three regions (north shore, Atauro Island, and Oecusse) of Timor-Leste. Each README.txt file contains specific details for each geoTiff generated.

File Type: Text

Distribution 3

CC ID: 569160
Download URL: https://www.pifsc.noaa.gov/library/pubs/tech/NOAA_Tech_Memo_PIFSC_46.pdf
Distributor: Pacific Islands Fisheries Science Center (PIFSC) (2015 - Present)
File Name: NOAA_Tech_Memo_PIFSC_46.pdf
Description:

Depth Derivation Using Multispectral WorldView-2 Satellite Imagery, a NOAA tech memo published by the Pacific Islands Fisheries Science Center. The Tech Memo is also available in the NOAA Repository.

File Date/Time: 2015-06-17 00:00:00
File Type: PDF

URLs

URL 1

CC ID: 569165
URL: https://www.coris.noaa.gov/activities/projects/timor-leste/
URL Type:
Online Resource
File Resource Format: HTML
Description:

Timor-Leste project portal on the NOAA Coral Reef Information Service website where NOAA's final report for Timor-Leste and the datasets generated by NOAA CREP as part of the project can be downloaded.

URL 2

CC ID: 572424
URL: https://dg-cms-uploads-production.s3.amazonaws.com/uploads/document/file/35/DG-8SPECTRAL-WP_0.pdf
URL Type:
Online Resource
File Resource Format: PDF
Description:

DigitalGlobe. 2010. The Benefits of the Eight Spectral Bands of WorldView-2.

URL 3

CC ID: 572426
URL: https://dg-cms-uploads-production.s3.amazonaws.com/uploads/document/file/98/WorldView2-DS-WV2-rev2.pdf
URL Type:
Online Resource
File Resource Format: PDF
Description:

WorldView-2 Data Sheet

URL 4

CC ID: 703748
URL: https://www.coris.noaa.gov/activities/projects/timor-leste/images/bathymetry.jpg
URL Type:
Browse Graphic
File Resource Format: JPG
Description:

An example of the bathymetry data generated for Timor-Leste from WorldView-2 satellite imagery.

URL 5

CC ID: 703749
URL: https://www.pifsc.noaa.gov/cred/coral_triangle_initiative.php
URL Type:
Online Resource
File Resource Format: PHP
Description:

Information about the NOAA Coral Reef Ecosystem Program's activities in the Coral Triangle.

Technical Environment

Description:

ENVI was used to process the satellite images, and maps and data were developed using ArcGIS. Spatial reference was UTM Zone 51S.

Data Quality

Accuracy:

The program Microsoft Excel was used for the multiple linear regression analysis to provide original variables for depth derivation. The multivariate slope intercept formula used to derive depth was Depth=Yint+(Mcoastal)(Xcoastal)+(Mblue)(Xblue)+(Mgreen)(Xgreen)+(Myellow)(XYellow).

Analytical Accuracy:

Multiple linear regression analysis using subsampled athymetry validation points.

Completeness Report:

Nearshore waters along the entire coastline of Timor-Leste have complete coverage of WorldView-2 satellite imagery. There are, however, holes in derived depths resulting from areas of high water column turbidity, clouds, whitewater, etc. that were masked out of the analyses due to a lack of reliable imagery of the seafloor for those areas. No bathymetry was generated for the southern coastline of Timor-leste because no depth data were available to calibrate the imagery and to subsequently validate the depths.

Conceptual Consistency:

Pre-processing of all WorldView-2 satellite images was performed using the same methods, to produce a rectified, deglinted image, with radiance and depth invariant data layers.

Quality Control Procedures Employed:

Based on the error analyses, derived bathymetry was clipped where statistical results were poor.

Data Management

Have Resources for Management of these Data Been Identified?: Yes
Approximate Percentage of Budget for these Data Devoted to Data Management: Unknown
Do these Data Comply with the Data Access Directive?: Yes
Is Access to the Data Limited Based on an Approved Waiver?: No
Approximate Delay Between Data Collection and Dissemination: Unknown
Actual or Planned Long-Term Data Archive Location: NCEI-CO
Approximate Delay Between Data Collection and Archiving: Unknown
How Will the Data Be Protected from Accidental or Malicious Modification or Deletion Prior to Receipt by the Archive?:

NOAA IRC and NOAA Fisheries ITS resources and assets.

Lineage

Lineage Statement:

Bathymetry data were derived for nearshore waters along the northern coastline of Timor-Leste, and the coastlines of Oecusse district and Atauro Island, from WorldView-2 satellite imagery following methods developed by Ehses and Rooney (2015).

Sources

Ehses , J.S., and J.J. Rooney. 2015. Depth derivation using multispectral WorldView-2 satellite imagery. U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-46, 24 p.

CC ID: 569169
Contact Type: Organization
Contact Name: Pacific Islands Fisheries Science Center, PIFSC
Publish Date: 2015-06-17
Citation URL: https://www.pifsc.noaa.gov/library/pubs/tech/NOAA_Tech_Memo_PIFSC_46.pdf

PIFSC. 2017. Interdisciplinary baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste: Final Report. NOAA Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-17-02, 234p.

CC ID: 703750
Contact Type: Organization
Contact Name: Pacific Islands Fisheries Science Center, PIFSC
Publish Date: 2017-06-21
Citation URL: https://doi.org/10.7289/V5/SP-PIFSC-17-002
Source Contribution:

The methods to derive depths from WorldView-2 satellite imagery for Timor-leste are described in Appendix C, and findings/results are summarized in Chapter 2. The data is presented in a 50+ page map book in Appendix D.

Process Steps

Process Step 1

CC ID: 569170
Description:

Satellite imagery was collected by the WorldView-2 commercial Earth observation satellite owned by DigitalGlobe. WorldView-2 provides panchromatic imagery of .46-meter resolution, and eight-band multispectral imagery with 1.84 meter (6 foot 0 inch) resolution.

Process Step 2

CC ID: 569171
Description:

Image pre-processing steps are described in the NOAA Technical Memorandum "Depth Derivation Using Multispectral WorldView-2 Satellite Imagery". Pre-processing of all WorldView-2 satellite images was performed using the same methods, to produce a deglinted image, radiance and depth invariant data layers.

Process Contact: Pacific Islands Fisheries Science Center (PIFSC)
Phone (Voice): 808-725-5300
Source: Ehses , J.S., and J.J. Rooney. 2015. Depth derivation using multispectral WorldView-2 satellite imagery. U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NMFS-PIFSC-46, 24 p.

Process Step 3

CC ID: 569172
Description:

The available ground-truth data (in-situ single beam depth data) was separated into two subsets; one subset was used to develop the multivariate slope intercept equation, and the second subset was used for the error analyses. The deglinted values of coastal, blue, green, and yellow bands were extracted in ArcGIS using the ground truth data set aside for the equation.

Process Step 4

CC ID: 569173
Description:

Multiple linear regression analysis of the extracted deglinted values and ground-truth data were performed in Excel and the multivariate slope intercept equation from the analysis was applied to the deglinted image in ENVI.

Process Step 5

CC ID: 569175
Description:

An error analysis was performed comparing the calculated depths with the second subset of the ground truth data. Depending on the results of the error analysis (the level of agreement between the derived data and the ground truth data), different formulas were tested using different combinations of the color bands to improve the results (i.e., different color bands from the satellite imagery were inserted into differing formulas to calculate the derived bathymetric data).

Process Step 6

CC ID: 569174
Description:

The derived bathymetry values that are out of range based on the error analysis were clipped out in ArcGIS.

Process Step 7

CC ID: 569176
Description:

A readme text file (README_FILE.txt) was prepared for each image used that catalogs the specific details for each set of derived depths, including the source image, processor names, dates, ground-truth data details, formulas, slope values, coefficients, and process steps.

Process Step 8

CC ID: 703751
Description:

The complete methodology followed to derive depths is described in the final report for Timor-Leste prepared by the NOAA Coral Reef Ecosystem Program.

Process Contact: Pacific Islands Fisheries Science Center (PIFSC)
Phone (Voice): 808-725-5300
Source: PIFSC. 2017. Interdisciplinary baseline ecosystem assessment surveys to inform ecosystem-based management planning in Timor-Leste: Final Report. NOAA Pacific Islands Fisheries Science Center, PIFSC Special Publication, SP-17-02, 234p.

Child Items

Rubric scores updated every 15m

Type Title
Entity (ENT) WV2_Bathy_TIMOR

Catalog Details

Catalog Item ID: 46150
Metadata Record Created By: Annette M DesRochers
Metadata Record Created: 2017-06-01 11:56+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2019-06-04 13:14+0000
Metadata Record Published: 2018-01-03
Owner Org: PIFSC
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Next Review Date: 2019-01-04