Update README.md

README.md

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-license: mit
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+UFO Sightings – Cleaned & Unified Dataset (~327k rows)
+
+This dataset merges several publicly available UFO sighting datasets from Kaggle into one cleaned, standardized, and enriched file.
+The goal is simply to provide a consolidated dataset instead of many fragmented sources with inconsistent formatting.
+
+This release contains a single JSONL file with approximately 327,000 records.
+
+No private or identifying information was present in the original data.
+
+📦 Source
+
+All entries originate from publicly available UFO sighting datasets on Kaggle.
+Each row corresponds to a single reported sighting.
+
+🧹 Cleaning / Normalization Performed
+
+All rows in this unified file were standardized using the same basic rules:
+
+timestamps parsed and converted into a consistent t_utc (ISO-8601, UTC)
+
+city/state/country fields harmonized where possible
+
+latitude/longitude coerced to floats
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+basic HTML/unicode cleanup in free-text descriptions (text)
+
+invalid or fully unparseable rows removed
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+source field preserved as src
+
+No interpretation or filtering based on content was performed.
+
+✨ Added Contextual Fields
+
+A small number of lightweight “sidecar” fields were added based on timestamp + coordinates:
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+moon_illum — moon illumination fraction
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+moon_alt_deg — moon altitude in degrees
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+nearest_airport_code — closest airport (ICAO)
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+nearest_airport_km — distance to that airport in km
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+wx_bucket — rough weather bucket (coarse category)
+
+These values are approximate and should be treated as exploratory metadata only.
+
+🧩 Clustering Fields (Included in the File)
+
+The dataset includes two fields that come from text-similarity grouping:
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+cluster_id — numeric label
+
+prob — membership confidence
+
+These reflect text similarity, not verified categories or event types.
+They are included because they were already part of the cleaned file.
+
+📝 Field Reference
+
+Each row has the following structure (example):