quirky megaliths

This is an identifier column: all 15464 values are unique with no nulls and no zeros, spanning 24151805 to 13537320281. The numeric stats (mean 4503184709.89, std 3470459882.49, skew 0.89) reflect ID allocation rather than a meaningful distribution. Treat the numeric summary as incidental. Treatment: Use as a join key; exclude from modelling features. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

15,464

min

2.415e+07

max

1.354e+10

mean

4.503e+09

median

3.411e+09

std

3.47e+09

q1

2.375e+09

q3

6.845e+09

iqr

4.471e+09

skew

0.8907

kurtosis

-0.2006

n_outliers

0

outlier_rate

0

zero_rate

0

This column records the OpenStreetMap geometry type for each record, taking only two values: "node" (13311 rows, 86%) and "way" (2153 rows). With cardinality of 2 and no nulls across 15464 rows, it's a clean binary categorical, though the 86/14 split means "way" is the clear minority class. Treatment: Encode as a binary indicator (e.g., is_node) before modelling. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

2

top_value

node

top_rate

0.8608

cardinality

2

entropy

0.5822

entropy_ratio

0.5822

This is a free-text 'name' field for megalithic monuments, mixing English, French, German, Italian and Cyrillic labels (e.g. 'Dolmen', 'Menhir', 'Großsteingrab', 'Нураге', 'Дольмен'). It is short (mean 13.6 chars, median 2 words) and heavily duplicated: 36.2% are repeats and 4720 rows (≈30%) are empty strings, leaving only 9869 unique values out of 15464. The vocabulary is dominated by generic monument types rather than proper names, so 37.8% are single-word entries. Treatment: Treat as a categorical type label after lowercasing and language-normalising; do not use as a unique identifier. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

9,869

len_min

0

len_max

84

len_mean

13.65

len_median

15

len_p95

30

word_mean

2.495

word_median

2

n_empty

4,720

n_duplicates

5,595

duplicate_rate

0.3618

vocab_size

9,447

readability_flesch_mean

46.9

emoji_rate

0

url_rate

0

one_word_rate

0.3782

allcaps_rate

0.003169

boilerplate_rate

0

This is a latitude coordinate column with 15320 unique values across 15464 rows and no nulls. Values span -51.81 to 65.17 with a median of 47.59 and Q1-Q3 of 42.95-50.52, indicating most observations cluster in the northern mid-latitudes (likely Europe/North America). The strong negative skew (-3.09) and high kurtosis (26.33) reflect a small tail of southern-hemisphere points pulling against an otherwise tight northern cluster, with 134 outliers flagged. Treatment: Pair with longitude as a geospatial feature; consider binning by region or projecting before modelling rather than using raw latitude. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

15,320

min

-51.81

max

65.17

mean

46.41

median

47.59

std

6.81

q1

42.95

q3

50.52

iqr

7.569

skew

-3.087

kurtosis

26.33

n_outliers

134

outlier_rate

0.008665

zero_rate

0

This column is longitude coordinates, with values spanning -151.36 to 144.74 across 15,464 rows and 15,407 unique values. The distribution is tightly concentrated around a median of -1.62 with an IQR of just 11.53, but a skew of 3.65 and kurtosis of 34.34 indicate heavy tails — 676 outliers (4.37%) reach far into the Pacific. No nulls or zeros, so coverage is clean. Treatment: Pair with latitude as a geospatial feature; consider projecting or binning rather than using raw values in a linear model. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

15,407

min

-151.4

max

144.7

mean

2.618

median

-1.62

std

14.64

q1

-3.083

q3

8.447

iqr

11.53

skew

3.654

kurtosis

34.34

n_outliers

676

outlier_rate

0.04371

zero_rate

0

Categorical type label for what appears to be megalithic monuments, with 19 distinct classes across 15,464 rows and no nulls. The distribution is severely imbalanced: 'megalith' alone covers 97.7% of records (15,113 rows), leaving rarer types like 'menhir' (156), 'dolmen' (83), and 'standing_stone' (59) as long-tail minorities. Entropy ratio of 0.049 confirms the column carries little discriminative signal in its raw form. Treatment: Collapse rare categories into 'other' or stratify/resample before using as a class label. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

19

top_value

megalith

top_rate

0.9773

cardinality

19

entropy

0.2096

entropy_ratio

0.04933

Categorical classification of megalithic structures across 73 distinct types, dominated by 'menhir' (33.8%) and 'dolmen', with a long tail including nuraghe, stone_circle, and passage_grave. Notable concern: 1,714 rows (~11%) carry an empty-string value despite a reported null_rate of 0.0, suggesting blanks are being treated as a valid category rather than missing. Entropy ratio of 0.44 indicates concentration in a few dominant types. Treatment: Recode empty strings to null, then one-hot encode the top categories and bucket the long tail as 'other'. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

73

top_value

menhir

top_rate

0.3383

cardinality

73

entropy

2.749

entropy_ratio

0.4441

Free-text description field for what appears to be megalithic/archaeological sites, with labels in multiple languages (Danish 'Jættestue', 'Langdysse'; Portuguese 'Anta da Herdade da Ordem'; German 'Großsteingrab'; English 'Stone circle', 'Long Barrow'). The column is effectively empty: 14,814 of 15,464 rows (top_rate 0.958) hold the empty string, leaving only ~650 populated rows spread across 586 distinct descriptions. Entropy ratio of 0.069 confirms the near-degenerate distribution, and the language mix means even the populated values won't cluster cleanly without normalization. Treatment: Drop or treat as a sparse free-text flag; not usable as a categorical feature given 96% empty and multilingual long tail. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

587

top_value

top_rate

0.958

cardinality

587

entropy

0.6328

entropy_ratio

0.0688

This column holds Wikipedia article references in `lang:Title` form (e.g. `de:Großsteingräber im Haldensleber Forst`, `fr:dolmen…`), pointing to megalithic-monument pages across multiple language editions. It is overwhelmingly empty: 13,060 of 15,464 rows are blank and the duplicate rate is 0.87, leaving only 2,058 distinct values across 15,464 rows. Where present, entries are short single tokens (one_word_rate 0.85, word_mean 1.35) and skew heavily German, with `de`-prefixed titles dominating the top values and words. Treatment: Treat as an optional cross-reference link; parse the `lang:title` prefix if needed but drop from modelling given 84% emptiness. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

2,058

len_min

0

len_max

75

len_mean

4.1

len_median

0

len_p95

29

word_mean

1.351

word_median

1

n_empty

13,060

n_duplicates

13,406

duplicate_rate

0.8669

vocab_size

2,769

readability_flesch_mean

5.48

emoji_rate

0

url_rate

0

one_word_rate

0.8524

allcaps_rate

0

boilerplate_rate

0

This column holds Wikidata Q-identifiers (e.g. Q106546933, Q1917052), one token per row with a max length of 10 characters. Coverage is poor: 10819 of 15464 rows are empty strings and only 4289 unique IDs appear, giving a 0.72 duplicate rate. The most frequent non-empty ID recurs only 17 times, so duplication is spread thinly rather than concentrated on a few entities. Treatment: Treat as an optional Wikidata key; left-join on non-empty values to enrich, and don't use as a feature directly. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

4,289

len_min

0

len_max

10

len_mean

2.667

len_median

0

len_p95

10

word_mean

1

word_median

1

n_empty

10,819

n_duplicates

11,175

duplicate_rate

0.7226

vocab_size

4,288

readability_flesch_mean

38.79

emoji_rate

0

url_rate

0

one_word_rate

1

allcaps_rate

0.3004

boilerplate_rate

0

Categorical heritage flag with 12 distinct values across 15464 rows and no nulls, but 87.96% of records carry an empty string, leaving only ~1862 rows with any signal. The non-empty values are a messy mix: numeric codes ('1','2','3','4','7'), yes/no, and free-text labels like 'Em Vias de Classificação' and 'Scheduled Monument', suggesting concatenated sources or inconsistent encoding schemes. Entropy ratio of 0.20 confirms the distribution is heavily concentrated in the blank class. Treatment: Normalise empty strings to null and harmonise the mixed numeric/yes-no/text codes before any encoding. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

12

top_value

top_rate

0.8796

cardinality

12

entropy

0.7343

entropy_ratio

0.2048

Categorical field naming the operator/agency responsible for a heritage record, with 31 distinct values across 15,464 rows and no nulls. It is overwhelmingly empty: the blank string accounts for 89.5% of rows (13,848), leaving only ~10% with an actual operator code such as 'mhs' (960), 'IE:smr' (229), or 'dgpc' (185). Entropy ratio of 0.14 confirms almost all signal lives in that empty bucket, and the value casing is inconsistent (lowercase codes alongside 'Historic Environment Scotland'). Treatment: Treat blanks as 'unknown' and normalise casing; only useful as a sparse categorical flag, not a primary feature. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

31

top_value

top_rate

0.8955

cardinality

31

entropy

0.7028

entropy_ratio

0.1419

A nominally date-like field that is effectively empty: 15,430 of 15,464 rows (top_rate 0.9978) carry the blank string, leaving only 34 populated cells across 25 other distinct values. Those rare entries are wildly inconsistent in format — ISO dates ('2004-07-01'), bare years ('1999'), BCE ranges ('between 3500 and 2800 BCE'), and codes ('C-30') — so even the non-null content is not parseable as a uniform timestamp. Entropy ratio of 0.0069 confirms there is essentially no information here. Treatment: Drop; near-constant blank with unparseable mixed-format residue. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

26

top_value

top_rate

0.9978

cardinality

26

entropy

0.03224

entropy_ratio

0.006859

This is a categorical 'material' attribute, almost certainly the OSM-style material tag for some physical feature, with 13 distinct values across 15,464 rows. It is overwhelmingly empty: 15,223 of 15,464 rows (top_rate 0.984) carry the blank string, leaving only ~241 actual material labels dominated by 'stone' (196) and 'granite' (29). Entropy ratio 0.036 confirms almost no information content, and the long tail includes a German 'Quarzit' and a compound 'stone;concrete' value, hinting at inconsistent tagging conventions. Treatment: Drop or treat empty as null and collapse rare variants; too sparse to use as a feature without aggressive grouping. high · anthropic:claude-opus-4-7

n

15,464

nulls

0 (0.0%)

unique

13

top_value

top_rate

0.9844

cardinality

13

entropy

0.1326

entropy_ratio

0.03582