Hamilton data projectWhich are the tallest falls in Hamilton's open data, and what does a mean hide?
The City of Hamilton publishes City Waterfalls, a file it describes as publicly accessible waterfalls in Hamilton, on both public and private property. We downloaded it on 22 October 2026 and analysed it with the program below. The figures are our counts, not the City's.
Our summary of the City of Hamilton City Waterfalls file (103 rows, downloaded 22 October 2026), by the COMMUNITY column| COMMUNITY in the file | Rows | Mean height (m) | Tallest (m) |
|---|
| Hamilton | 41 | 10.8 | 39.5 |
| Flamborough | 23 | 9.9 | 41 |
| Stoney Creek | 17 | 11.1 | 37 |
| Ancaster | 15 | 8.0 | 21 |
| Dundas | 6 | 5.4 | 9 |
| Burlington | 1 | 25.0 | 25 |
Two small functions do most of the work: one loads the file, one takes a mean. The sort uses a key function, which tells sorted() to order whole records by a single field. This program, run on the saved file, printed every number on this page:import json
def load_falls(path):
with open(path, encoding="utf-8") as f:
return [feature["attributes"] for feature in json.load(f)["features"]]
def mean(values):
return sum(values) / len(values)
falls = load_falls("waterfalls.json")
tallest = sorted(falls, key=lambda fall: fall["HEIGHT_IN_M"], reverse=True)
for fall in tallest[:5]:
print(fall["NAME"], fall["HEIGHT_IN_M"], "m", fall["COMMUNITY"])
for kind in ("Waterfall", "Cascade"):
heights = [fall["HEIGHT_IN_M"] for fall in falls if fall["TYPE"] == kind]
print(kind, len(heights), round(mean(heights), 1))
by_community = {}
for fall in falls:
by_community.setdefault(fall["COMMUNITY"], []).append(fall["HEIGHT_IN_M"])
for place, heights in sorted(by_community.items()):
print(place, len(heights), round(mean(heights), 1), max(heights))
The five tallest
Sorted by HEIGHT_IN_M, the file puts Tew's Falls first at 41 m, then Lower Princess Falls at 39.5 m, Devil's Punchbowl Falls at 37 m, Ferguson Falls at 30 m and Snake Falls at 25 m.
Waterfall or cascade
The TYPE column splits the rows into 47 waterfalls with a mean height of 12.5 m and 56 cascades with a mean of 8.1 m. Students then ask whether the tallest few are pulling the waterfall mean up.
A one-row community
Snake Falls is the only row whose COMMUNITY is Burlington, so Burlington's mean of 25.0 m rests on a single record. A student who prints that mean without the count of 1 beside it has made a misleading table.
Mean against median
Across all 103 rows the median height is 7 m and 11 rows sit at the minimum of 3 m, while every community mean in the table is higher than 7 m except Dundas. A few tall drops lift a mean; the median shows the typical row. Writing both, with the counts, is the honest report.
Some columns are not explained in the file itself. RANKING holds A on 18 rows, B on 36 and C on 49, and OWNERSHIP includes a value written public-I on 28 rows. We teach students to say they do not know what a code means rather than invent a meaning, and to look for the publisher's documentation first. The data is used under the City of Hamilton Open Data Licence: contains public sector Data made available under the City of Hamilton's Open Data Licence (licence). The City does not endorse this page or these classes, and a file of accessible falls is not advice about visiting them.
