quirky caves

This column is almost certainly a row identifier: all 69716 values are unique with zero nulls, and the numeric range spans roughly 1.28e7 to 1.354e10 with near-zero skew (0.02) and negative kurtosis (-1.18), consistent with broadly distributed assigned IDs rather than a measured quantity. No outliers or zeros are flagged. Treat the numeric stats as incidental — the magnitudes carry no analytical meaning. Treatment: Drop from modelling; retain only as a join key. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

69,716

min

1.279e+07

max

1.354e+10

mean

6.842e+09

median

7.007e+09

std

3.774e+09

q1

3.61e+09

q3

9.948e+09

iqr

6.338e+09

skew

0.01955

kurtosis

-1.177

n_outliers

0

outlier_rate

0

zero_rate

0

Short free-text names of caves/caverns in mixed languages (English 'Cave', French 'Grotte', Italian 'Grotta', Spanish 'Cueva', Cyrillic 'Грот', German 'Bärenhöhle'), averaging 2.5 words and 15.5 characters. Severe duplication (35.1%, 24,487 rows) is dominated by the placeholder 'Unnamed Cave' appearing 19,527 times — over a quarter of all rows are effectively unlabelled. Of 69,716 rows only 45,229 are unique, and the vocabulary of 15,219 tokens reflects the multilingual mix. Treatment: Treat 'Unnamed Cave' as missing and language-normalise before any text matching or grouping. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

45,229

len_min

1

len_max

143

len_mean

15.52

len_median

13

len_p95

29

word_mean

2.519

word_median

2

n_empty

0

n_duplicates

24,487

duplicate_rate

0.3512

vocab_size

15,219

readability_flesch_mean

55.51

emoji_rate

1.434e-05

url_rate

0

one_word_rate

0.1545

allcaps_rate

0.03242

boilerplate_rate

0

Latitude coordinates spanning -77.98 to 78.18, so the column covers nearly the full globe from Antarctic to Arctic ranges. The distribution is heavily left-skewed (skew -3.16, kurtosis 11.5) with a tight IQR of 7.26 around a median of 44.14, indicating most points cluster in northern mid-latitudes while a long tail of southern-hemisphere values produces 8,996 outliers (12.9%). Near-unique values (69,544 of 69,716) confirm these are precise geocoordinates rather than bucketed regions. Treatment: Pair with longitude for geospatial features; consider binning or projecting rather than treating as a raw scalar. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

69,544

min

-77.98

max

78.18

mean

40.58

median

44.14

std

15.48

q1

40.49

q3

47.75

iqr

7.256

skew

-3.161

kurtosis

11.5

n_outliers

8,996

outlier_rate

0.129

zero_rate

0

This is a longitude coordinate, with values spanning the full -178.00 to 178.80 range and 69,585 unique values across 69,716 rows. The distribution is centered near 12.03 (median 11.38) with IQR 1.24 to 18.18, suggesting a heavy concentration in European/African longitudes, but the std of 40.50 and 16.2% flagged outliers reveal a long global tail. No nulls or zeros are present. Treatment: Pair with latitude for geospatial features; do not treat outliers as errors since the global range is legitimate. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

69,585

min

-178

max

178.8

mean

12.03

median

11.38

std

40.5

q1

1.245

q3

18.18

iqr

16.94

skew

0.2755

kurtosis

4.509

n_outliers

11,302

outlier_rate

0.1621

zero_rate

0

A free-text 'description' field, but 65189 of 69716 rows (94.7% duplicate rate) are empty strings, leaving only ~4500 populated entries with a mean length of 3.46 characters and median word count of 1. The non-empty values are short multilingual fragments — German ('nicht katasterwürdig', 'unterer Eingang'), French ('Entrée d'une carrière souterraine'), and other tokens like 'cave' and 'Halbhöhle' — suggesting cave/feature annotations rather than prose. With 92.8% one-word rate and a vocab of 4651, this is closer to sparse tagging than narrative text. Treatment: Treat as sparse optional tag: flag presence as a boolean feature and ignore the text body unless modelling the populated subset. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

3,705

len_min

0

len_max

255

len_mean

3.462

len_median

0

len_p95

19

word_mean

1.455

word_median

1

n_empty

65,189

n_duplicates

66,011

duplicate_rate

0.9469

vocab_size

4,651

readability_flesch_mean

1.752

emoji_rate

0

url_rate

0.0006311

one_word_rate

0.9428

allcaps_rate

0.00241

boilerplate_rate

1.434e-05

Categorical access-permission tag, almost certainly the OSM-style `access` key indicating who may use a feature. 89.7% of the 69,716 rows are empty strings, leaving only ~10% with substantive values like `yes` (2,717), `no` (2,266), `private` (815), `permit` (575), and `permissive` (440). Entropy ratio is just 0.16 and 20 distinct values appear, so the signal is sparse but the long tail (`customers`, `destination`, `restricted`, `unknown`) is meaningful when present. Treatment: Treat empty string as missing, then collapse rare levels and one-hot encode the survivors. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

20

top_value

top_rate

0.8972

cardinality

20

entropy

0.7067

entropy_ratio

0.1635

This is an OSM-style `tourism` tag categorising features like attractions, viewpoints, and museums across 18 distinct values. The column is severely imbalanced: 97.2% of the 69,716 rows are empty strings, with `attraction` (1,670) and `viewpoint` (119) the only non-trivial categories. Entropy ratio of 0.05 confirms almost no information content as-is. Treatment: Treat empty string as missing and either drop or collapse rare categories into a binary `is_tourism` flag. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

18

top_value

top_rate

0.9722

cardinality

18

entropy

0.2076

entropy_ratio

0.04979

This column holds Wikipedia article references in the OSM-style `lang:Article Title` format (e.g. `de:Einödhöhle`, `fr:Grotte...`), mostly pointing to cave-related pages across many languages. It is overwhelmingly empty: 67,531 of 69,716 rows are blank and the duplicate rate is 0.97, leaving only 2,077 unique values. Among the populated entries, language prefixes span de, fr, pl, es, it, ca, en, ru and more, so any downstream use must handle multilingual strings. Treatment: Split into language prefix and title, and treat as a sparse optional reference rather than a modelling feature. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

2,077

len_min

0

len_max

114

len_mean

0.636

len_median

0

len_p95

0

word_mean

1.044

word_median

1

n_empty

67,531

n_duplicates

67,639

duplicate_rate

0.9702

vocab_size

940

readability_flesch_mean

-0.02485

emoji_rate

0

url_rate

0

one_word_rate

0.9756

allcaps_rate

0

boilerplate_rate

0

This is a website/URL field for each record, but it is overwhelmingly empty: 67,082 of 69,716 rows (n_empty) are blank, leaving only 2,492 unique values across the column. Where populated, entries are single-token URLs (one_word_rate 0.99998, word_mean ~1.0) pointing to varied external domains (angloasianmining.com, unesco.org, termeszetvedelem.hu, etc.). The duplicate_rate of 0.96 is driven almost entirely by the empty string, and url_rate is only 0.038 because the metric is computed over all rows including blanks. Treatment: Treat as optional reference URL; impute missing as null and avoid using as a feature given >96% blanks. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

2,492

len_min

0

len_max

255

len_mean

2.789

len_median

0

len_p95

0

word_mean

1

word_median

1

n_empty

67,082

n_duplicates

67,224

duplicate_rate

0.9643

vocab_size

737

readability_flesch_mean

-24.04

emoji_rate

0

url_rate

0.03775

one_word_rate

1

allcaps_rate

1.434e-05

boilerplate_rate

0

This appears to be a cave length attribute (likely OpenStreetMap-style tag) stored as a string, with 99.08% of the 69,716 rows being empty and only 238 distinct values overall. When populated, values look like small integers (5, 6, 10, 3, 4...) suggesting metres, but the signal is so sparse (entropy ratio 0.0176) that it carries almost no information. The non-null counts in the top values are tiny (≤32 each), indicating this tag is rarely filled in upstream. Treatment: Drop or convert to a numeric 'has_length' indicator; the column is too sparse to model directly. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

238

top_value

top_rate

0.9908

cardinality

238

entropy

0.1392

entropy_ratio

0.01763

This appears to be a cave depth attribute, likely sourced from an OpenStreetMap-style tag, stored as strings. It is effectively empty: 69,419 of 69,716 rows (top_rate 0.9957) carry the blank value "", and the remaining 124 distinct values are tiny integer-like strings ranging from "0" to "30" with single- or low-double-digit counts. Entropy ratio of 0.0092 confirms there is virtually no signal here. Treatment: Drop; near-constant blank with negligible entropy. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

124

top_value

top_rate

0.9957

cardinality

124

entropy

0.06432

entropy_ratio

0.00925

Two-letter ISO country code, but effectively empty: 69,684 of 69,716 rows (top_rate 0.9995) carry a blank string, leaving only 32 rows spread across 15 actual codes (KY, AU, DE, RO, US, etc.). Entropy ratio of 0.0018 confirms there is essentially no signal here. No nulls are reported because the missingness is encoded as empty string rather than NULL. Treatment: Drop; near-constant empty string with only 32 populated rows. high · anthropic:claude-opus-4-7

n

69,716

nulls

0 (0.0%)

unique

16

top_value

top_rate

0.9995

cardinality

16

entropy

0.00736

entropy_ratio

0.00184