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| Dataset Title: | Landsat Satellite Coordinates version 4, Mt. Hope Bay
|
| Institution: | Rhode Island Data Discovery/United States Geological Survey (Dataset ID: landsat_sst_mthope_v4_grid) |
| Information: | Summary
| License
| Metadata
| Background
| Make a graph
|
Attributes {
Y {
Int16 actual_range 0, 375;
String comment "Row index of the Landsat data files; increases northward.";
String long_name "Y";
String source_name "Y";
String units "count";
}
X {
Int16 actual_range 0, 267;
String comment "Column index of the Landsat data files; increases eastward.";
String long_name "X";
String source_name "X";
String units "count";
}
Longitude {
Float64 colorBarMaximum -71.1;
Float64 colorBarMinimum -71.5;
String grid_mapping "crs";
String long_name "longitude of pixel center";
String standard_name "longitude";
String units "degrees_east";
}
Latitude {
Float64 colorBarMaximum 41.8;
Float64 colorBarMinimum 41.4;
String grid_mapping "crs";
String long_name "latitude";
String standard_name "latitude";
String units "degrees_north";
}
NC_GLOBAL {
String _NCProperties "version=2,netcdf=4.9.2,hdf5=1.14.4";
String cdm_data_type "Grid";
String comment "Values are pixel CENTERS on the native Landsat lattice: 30 m, axis-aligned in WGS 84 / UTM zone 19N (EPSG:32619). Easting = pixel_00_center_easting_m + 30*X, Northing = pixel_00_center_northing_m + 30*Y. Arrays are [Y][X], matching the [time][Y][X] order of the temperature datasets (the version 2 and 3 coordinate datasets were [X][Y]). Mt. Hope Bay is the sub-window Y 695-1070, X 509-776 of Narragansett Bay. The lattice was determined by matching version 2 temperatures to the USGS Landsat Collection 2 Level-2 surface temperature scenes (the source Earth Engine serves): for Landsat 5, 7 and 8 scenes more than 99.7 percent of pixels equal the scene value plus a constant at a single integer offset. With these coordinates the Landsat land/water mask agrees with the OSOM land mask at 96.4 percent of pixels (83.1 percent with version 3 coordinates) and with NOAA BlueTopo at 93.1 percent (82.0 percent); residual offsets against both coastlines are 30 m or less.";
String Conventions "COARDS, CF-1.6, ACDD-1.3";
String creator_name "Rhode Island Data Discovery/United States Geological Survey";
String defaultGraphQuery "Longitude[0:last][0:last]&.draw=surface&.vars=X|Y|Longitude";
String history
"2026-09-30T17:14:21Z created by step6_write_v4.py (LandSatCoordGlitch repository)
2026-11-12T07:50:44Z (local files)
2026-11-12T07:50:44Z http://qa-erddap.riddc.brown.edu/erddap/griddap/landsat_sst_mthope_v4_grid.das";
String infoUrl "https://earthexplorer.usgs.gov/ accessed through https://code.earthengine.google.com/";
String institution "Rhode Island Data Discovery/United States Geological Survey";
String keywords "bay, coordinates, data, discovery, geological, hope, island, landsat, latitude, longitude, rhode, satellite, states, survey, united, version";
String license
"The data may be used and redistributed for free but is not intended
for legal use, since it may contain inaccuracies. Neither the data
Contributor, ERD, NOAA, nor the United States Government, nor any
of their employees or contractors, makes any warranty, express or
implied, including warranties of merchantability and fitness for a
particular purpose, or assumes any legal liability for the accuracy,
completeness, or usefulness, of this information.";
Float64 pixel_00_center_easting_m 311490.0;
Float64 pixel_00_center_northing_m 4611300.0;
Float64 pixel_size_m 30.0;
String publication "https://doi.org/10.26300/ja0b-xa86";
String publisher_url "https://riddc.brown.edu/";
String recap "PROBLEM: the version 2 and version 3 Landsat Satellite Coordinates datasets are an evenly spaced latitude-longitude lattice stretched across a bounding box (71.45-71.15 W, 41.45-41.75 N for Narragansett Bay). The imagery is an unresampled crop of USGS Landsat Collection 2 Level-2 scenes and sits on the native Landsat lattice: 30 m pixels, axis-aligned in WGS 84 / UTM zone 19N (EPSG:32619), rotated about 1.5 degrees from the meridian here. Every version 2/3 position is wrong: by 516-1450 m (median 630 m) in Narragansett Bay and 150-967 m (median 384 m) in Mt. Hope Bay. VERSION 4 LATTICE: pixel centers at Easting = E0 + 30*X, Northing = N0 + 30*Y, with E0 = 296220 m, N0 = 4590450 m (800 x 1130) for Narragansett Bay and E0 = 311490 m, N0 = 4611300 m (268 x 376) for Mt. Hope Bay; longitude and latitude are the inverse UTM 19N projection. Mt. Hope Bay is the sub-window Y 695-1070, X 509-776 of Narragansett Bay. HOW IT WAS PINNED: version 2 temperatures equal the source scene surface-temperature band plus a constant at a single integer offset, for 100.00 percent (Landsat 5, 1984-05-02), 99.86 percent (Landsat 7, 1999-07-07) and 99.74 percent (Landsat 8, 2013-04-04) of pixels; all three scenes (WRS-2 path 12 row 31) give the same lattice. Scenes were read from the Microsoft Planetary Computer mirror of the USGS archive, the same scenes Google Earth Engine serves; the original Earth Engine export script was not available. CONSISTENCY: Landsat land/water mask agreement with the OSOM land mask rises from 83.1 percent (version 3 coordinates) to 96.4 percent (version 4), residual offset +15 m east, -30 m north; with NOAA BlueTopo (depth below zero) from 82.0 to 93.1 percent, residual +15 m east, 0 m north. WHAT THOSE PERCENTAGES MEAN: OSOM and BlueTopo agree with each other at 94.8 percent of the same pixels, and all three agree at 92.1 percent. Shifting the Landsat mask against itself gives 98.0 percent at 1 pixel (42 m), 96.4 percent at 2 pixels (85 m), 92.6 percent at 5 pixels (212 m), 79.0 percent at 21 pixels (891 m). 84 percent of Landsat-OSOM and 60 percent of Landsat-BlueTopo disagreements lie within 3 pixels of a shoreline; 1.7 percent of pixels are water in Landsat and OSOM but unsurveyed in BlueTopo. The remaining disagreement is shoreline definition, not position. CHANGES FROM VERSION 3: corrected positions; arrays are [Y][X] (were [X][Y]) to match the [time][Y][X] temperature datasets; 64-bit values; Easting and Northing added. LIMITS: only path 12 scenes were tested; path 13 scenes (delivered in UTM zone 18N) would have been resampled by Earth Engine onto this lattice. Residual offsets are resolved to 15 m. SIDE FINDINGS, NOT FIXED: version 2 data equal the scene +0.450 degC (Landsat 5), +1.094 degC (Landsat 7), -0.178 degC (Landsat 8), the opposite sign to the version 2 metadata; a few temperatures are unphysical (near -106 and -124 degC). Full description: report/landsat_v4_coordinates.pdf in the LandSatCoordGlitch repository, 2026-09-30.";
String source "USGS Landsat Collection 2 Level-2 (LANDSAT/LT05, LE07, LC08 C02 T1_L2), WRS-2 path 12 row 31";
String sourceUrl "(local files)";
String standard_name_vocabulary "CF Standard Name Table v55";
String summary "Translation from x,y coordinates to latitude and longitude for the \"Landsat Satellite Surface Temperature v2 and v3\" datasets.";
String title "Landsat Satellite Coordinates version 4, Mt. Hope Bay";
}
}
Data Access Protocol (DAP) and its
projection constraints.
The URL specifies what you want: the dataset, a description of the graph or the subset of the data, and the file type for the response.
griddap request URLs must be in the form
https://coastwatch.pfeg.noaa.gov/erddap/griddap/datasetID.fileType{?query}
For example,
https://coastwatch.pfeg.noaa.gov/erddap/griddap/jplMURSST41.htmlTable?analysed_sst[(2002-06-01T09:00:00Z)][(-89.99):1000:(89.99)][(-179.99):1000:(180.0)]
Thus, the query is often a data variable name (e.g., analysed_sst),
followed by [(start):stride:(stop)]
(or a shorter variation of that) for each of the variable's dimensions
(for example, [time][latitude][longitude]).
For details, see the griddap Documentation.