@prefix this: <https://w3id.org/sciencelive/np/RANLZSWPo1AXNszhQDilv20UB6wM32Gp6WzbUhTCfzUK4> .
@prefix sub: <https://w3id.org/sciencelive/np/RANLZSWPo1AXNszhQDilv20UB6wM32Gp6WzbUhTCfzUK4/> .
@prefix np: <http://www.nanopub.org/nschema#> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix prov: <http://www.w3.org/ns/prov#> .
@prefix npx: <http://purl.org/nanopub/x/> .
@prefix dc: <http://purl.org/dc/terms/> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .

<https://w3id.org/sciencelive/np/RANLZSWPo1AXNszhQDilv20UB6wM32Gp6WzbUhTCfzUK4> a
    np:Nanopublication, npx:ExampleNanopub;
  np:hasAssertion sub:assertion;
  np:hasProvenance sub:provenance;
  np:hasPublicationInfo sub:pubinfo;
  dc:created "2026-04-09T20:59:47.543Z"^^xsd:dateTime;
  dc:creator <https://orcid.org/0000-0002-1784-2920>;
  dc:license <https://creativecommons.org/licenses/by/4.0/>;
  npx:introduces sub:healpix-wgs84;
  npx:wasCreatedAt <https://platform.sciencelive4all.org>;
  <http://www.w3.org/2000/01/rdf-schema#label> "NP created using Declaring a replication study outcome according to FORRT";
  <https://w3id.org/np/o/ntemplate/wasCreatedFromTemplate> <https://w3id.org/np/RA2zljn0Nw9SadppOyxZoh-_Rxosslrq-vYG-p9SttnJE> .

sub:healpix-wgs84 a <https://w3id.org/sciencelive/o/terms/FORRT-Replication-Outcome>;
  <http://schema.org/endDate> "2026-04-08";
  <http://www.w3.org/2000/01/rdf-schema#label> "WGS84 Ellipsoid Significantly Affects HEALPix Cell Assignment at Mid and High Latitudes";
  <https://w3id.org/sciencelive/o/terms/hasConclusionDescription> "WGS84 ellipsoid indexing assigns pixels to substantially different HEALPix cells than sphere-based indexing, particularly at mid and high latitudes. At mid-latitudes (+48°), 98% of pixels are assigned to a different cell. This demonstrates that sphere-based HEALPix indexing is unsuitable for European Earth observation data (Copernicus/Sentinel, 45-65°N). ";
  <https://w3id.org/sciencelive/o/terms/hasConfidenceLevel> <https://w3id.org/sciencelive/o/terms/HighConfidence>;
  <https://w3id.org/sciencelive/o/terms/hasEvidenceDescription> """  ELLIPSOID ANALYSIS (HEALPix depth 9, sphere vs WGS84):
                                                        
  | Region        | Center lat | Pixels in different cell | Jaccard similarity |                                                                  
  |---------------|------------|--------------------------|-------------------|                                                                   
  | Equatorial    | 0°         | 26.6%                    | 0.9951            |                                                                   
  | Mid-latitude  | +48°       | 98.4%                    | 0.9844            |                                                                   
  | High-latitude | +62°       | 90.8%                    | 0.9868            |
  | Arctic        | +78°       | 52.6%                    | 0.9908            |                                                                   
                                                                               
  At mid-latitudes (Mediterranean, +48°), nearly every pixel (98.4%) is assigned to a different HEALPix cell when using sphere vs WGS84 ellipsoid.
   Polygon coverage Jaccard similarity drops to 0.9844, indicating measurable differences in spatial coverage. The effect peaks at mid-latitudes  
  where the WGS84 ellipsoid deviates most from a sphere, and decreases towards the equator and poles. """;
  <https://w3id.org/sciencelive/o/terms/hasLimitationsDescription> """  - Uses synthetic raster grids, not real Earth observation data
  - Single HEALPix depth (9) tested -- effect may vary at other depths                                                                            
  - Four latitude bands only; continuous latitude sweep not performed 
  - Does not quantify downstream impact on scientific analyses (e.g., land cover classification accuracy)    """;
  <https://w3id.org/sciencelive/o/terms/hasOutcomeRepository> <https://doi.org/10.5281/zenodo.19488374>;
  <https://w3id.org/sciencelive/o/terms/hasValidationStatus> <https://w3id.org/sciencelive/o/terms/Validated>;
  <https://w3id.org/sciencelive/o/terms/isOutcomeOf> <https://w3id.org/sciencelive/np/RAocR3vJTYJPEfL8vIBN2cjEFie2vT-tvhOS7IA431Dqk/healpix-replication2> .

sub:assertion prov:wasAttributedTo <https://orcid.org/0000-0002-1784-2920> .

<https://orcid.org/0000-0002-1784-2920> <http://xmlns.com/foaf/0.1/name> " Anne Fouilloux" .

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  npx:hasSignature "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";
  npx:hasSignatureTarget <https://w3id.org/sciencelive/np/RANLZSWPo1AXNszhQDilv20UB6wM32Gp6WzbUhTCfzUK4>;
  npx:signedBy <https://orcid.org/0000-0002-1784-2920> .