openmaptiles/openmaptiles-tools

Enhanced height parser.

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#463 opened on Dec 1, 2025

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Description

Based on taginfo, there are at least 137k heights with the value 2 m, 105k with value 3 m, 71k 6 m... The current function CleanNumeric handles simple strings and converts them to a number (SELECT cleannumeric('2.0'::text); -> 2::numeric).

The function should not replace CleanNumeric function, but be another function to deal with these non-numeric values (with m, m, ft, ", ' ",...)

The new function will be used for parsing heights for buildings, for mountain_peak, and for aerodrome_label layers.

One attempt was already discussed in #362.

Contributor guide

Research direction
Examine the existing CleanNumeric function in CleanNumeric.sql, understand the height value formats (e.g., '2 m', '3 ft'), and implement a new SQL function to parse these non numeric heights into numeric values. Refer to the linked building, mountain peak, and aerodrome label SQL files for usage context.
Tech stack
pythonsql
Domain
backendapidatabase
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
SQLPostgreSQL
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70