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COOK ISLANDS 2026
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Regional context

Atiu

Atiu

HS101 Matai

Surveyed 2026-05-26

Map layers

Site assets

Daily logs

May 26, 2026

Model color relief

Colors distinguish relative surface relief in the model and are paired with hillshade. No validated elevation scale or tidal-datum tie is published here.

Site assets

Photos

Photo review

Field photographs

507 photos

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GPS ledger

Coordinates and point heights

CSV

Each value belongs to one GPS row; it is not a single elevation for the site. The CSV distinguishes local-datum height from receiver altitude.

IDLatLonPoint heightV. accuracy
Matai Beach -20.017516108 -158.1021263385 6.26 0.179
Matai base -20.017516738135 -158.10212767323 6.28 0.088615
Matai base -20.01751652985 -158.102127040127 6.20 0.054475
Matai base -20.0175165797758 -158.102126932172 6.22 0.05214
Matai base -20.0175166530408 -158.102126950689 6.20 0.056825
GCP3 Matai Base -20.0175167098617 -158.102126775828 6.23 0.05452
GCP4 -20.0180751462475 -158.103190012492 6.28 0.05701
GCP1 -20.0179752552533 -158.102836567138 5.54 0.05632
GCP5 -20.0175945489442 -158.102003967099 7.02 0.054025
GCP7 -20.0178880196917 -158.102575710217 5.83 0.06388
HS101B -20.0178937422375 -158.102573955918 5.25 0.06226
HS101C -20.0179711450208 -158.102687899127 4.66 0.065515
HS101D -20.0180048309517 -158.102813597194 4.74 0.059385
HS101E -20.0180056357 -158.102913098504 7.19 0.06013
HS101F -20.0178821822558 -158.103010965466 8.49 0.075675
HS101G -20.0176262088417 -158.102564568839 8.57 0.069425
HS101A -20.0178681814425 -158.102424835467 4.33 0.068275
Matai base RCC point a -20.0175168005367 -158.102127672683 6.21 0.083874

Samples

Sample list

SampleTypeTime CKTPositionPhotos
HS101A Fossilized coral 2026-05-26 13:33 -20.017868, -158.102425
4.333 m
HS101B Fossilized coral 2026-05-26 12:58 -20.017894, -158.102574
5.252 m
HS101C Fossilized coral 2026-05-26 13:04 -20.017971, -158.102688
4.663 m
HS101D Fossilized coral 2026-05-26 13:11 -20.018005, -158.102814
4.736 m
HS101E Fossilized coral 2026-05-26 13:16 -20.018006, -158.102913
7.188 m
HS101F Fossilized coral 2026-05-26 13:24 -20.017882, -158.103011
8.491 m
HS101G Fossilized coral 2026-05-26 13:27 -20.017626, -158.102565
8.573 m

Raster data

Download site rasters

Manifest

The map’s DEM layer is a hillshade visualization. These links provide the source elevation raster and orthophoto as GeoTIFFs for local analysis. The DEM uses the island-specific datum.

Raw DEM GeoTIFF HS101_dem.tif · 16.2 MiB EPSG:4326 · Float32 · 1 band
Download
Orthophoto GeoTIFF HS101_orthophoto_rgba.tif · 87.7 MiB EPSG:4326 · Byte · 4 bands
Download

SHA-256 checksums are included in the public manifest for reproducibility.

DEM transects

Topographic profiles

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No vertical exaggeration. Profiles run southeast to northwest across the DEM raster.

Animated geology plate

HS101: Matai

Atiu, Cook Islands

Surveyed 2026-05-26

HS101: Matai

Explore Matai’s lower, beach-facing branching-coral exposure with one close view and its matching field photograph.

Field notes

Field photographs show upward branching coral fabric in the lower, beach-facing exposure. The 26 May field record describes large colonies in growth position, branches up to about 1 cm and corallites about 2 mm. The original photograph is registered to this model exposure using rock landmarks; it carries finer fabric detail than the reconstruction. The field notes report no clear separating sand layer or hiatus. No age, hiatus, precise taxon or sea-level datum is assigned. Vegetation hides much of the landward surface; roadside material may include moved boulders. Moving water and field gear are not geological evidence. All 417 cameras are aligned in one reviewed natural-tie network. A questionable unpinned control projection remains unedited. Reviewed sections and source-photo comparisons showed no broad doubled exposed surface; this is not a whole-site accuracy certification. Gray sides and backing are artificial presentation geometry. Original retained geometry, UVs and 18 diffuse plus 18 normal 8K maps are preserved.

F1 · Lower branching coral: field photograph (opens in a new tab)
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Cook Islands 2026

Southern Cook Islands
May to June 2026

Daily Logs Sites Data Downloads Samples Tidal Datums Report Progress Legacy Archive

The Cook Islands 2026 field campaign is part of HISEAS, funded by the U.S. National Science Foundation (NSF), EAR 24-20482 (2024–2029).