hdb-valuation-engine 0.1.0

Singapore Public Housing (HDB) Valuation Engine using geospatial accessibility scoring.

HDB Valuation Engine 🇸🇬

A quantitative tool for identifying undervalued Singapore public housing assets using spatial data analysis.

The Real-World Problems

1. The LRT Deception: Commercial portals treat LRT (Light Rail) and MRT (Heavy Rail) as equal. This is false. LRT loops add significant commute latency. Buyers need a metric that rewards True Connectivity.
2. The Lease Illusion: Buyers often fixate on raw price, ignoring lease decay. A 'cheap' flat with 50 years remaining is often a worse asset than a pricier unit with 95 years.
3. Data Overload: With thousands of transactions, manual comparisons are impossible. Buyers need statistical anomaly detection, not just a search bar.

The Engineering Solution

This engine ingests historical transaction data to calculate a 'True Value Score' for every flat.

• LRT-Exclusion Algorithm: Uses Regex filtering and KDTree spatial indexing to calculate walking distance strictly to MRT nodes.
• Depreciation Logic: Normalizes price against remaining lease life to find the true cost of ownership.
• Z-Score Ranking: Identifies properties trading 2 deviations below their cluster average.

---

Key Features

• Strict OOP pipeline with type hints and logging
• Robust lease parsing and inference (handles text and infers from lease_commence_date + month)
• Lease-adjusted price efficiency metric and group-wise Z-Score valuation
• Extended filters (exact/partial) and numeric ranges
• TransportScorer with KDTree and strict LRT exclusion (regex ^(BP|S[WE]|P[WE]))
• Export to CSV/JSON/Parquet; optional full export
• Configurable peer grouping via --group-by
• Caching for fast repeated transport queries; cache management subcommand

Algorithm Overview

1. Lease parsing/inference
   • Parse remaining_lease strings to float years (e.g., 61 years 04 months → 61.33).
   • If absent, infer years: remaining_years = 99 - ((YYYY + (MM-1)/12) - lease_commence_year).
2. Price efficiency
   • price_efficiency = resale_price / (floor_area_sqm * remaining_lease_years)
3. Group-wise Z-Score
   • Group by --group-by (default: town, flat_type) and compute z = (x - μ) / σ.
4. Valuation score
   • valuation_score = - z_price_efficiency (higher → more undervalued).
5. Transport accessibility (optional)
   • Compute nearest MRT exit distance (LRT excluded) and Accessibility_Score = max(0, 10 - 2 * dist_km).
   • By default adjusts price_efficiency; use --no-accessibility-adjust for analysis-only.

Installation

From PyPI:

pip install hdb-valuation-engine

From source (recommended in a virtual environment):

python3 -m venv .venv
source .venv/bin/activate  # Windows: .venv\\Scripts\\Activate.ps1
pip install -r requirements.txt

Quick Start

Platform-agnostic data fetching (no Make needed):

• Fetch all supported datasets (HDB resale CSV + MRT exits GeoJSON):

hdb-valuation-engine fetch

• Fetch entire HDB resale dataset (no row limit) plus MRT exits:

hdb-valuation-engine fetch --limit 0

• Only MRT exits to a custom path:

hdb-valuation-engine fetch --datasets mrt --mrt-out .data/LTAMRTStationExitGEOJSON.geojson

• Only HDB resale CSV with 10k rows to default location:

hdb-valuation-engine fetch --datasets resale --limit 10000

Programmatic usage:

from hdb_valuation_engine import HDBValuationEngine
import argparse

app = HDBValuationEngine()
args = argparse.Namespace(
    input="ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv",
    town="PUNGGOL",
    budget=600000,
    top=5,
    verbose=1,
    mrt_catalog=None,
    group_by=None,
    output=None,
    export_full=False,
    output_format="csv",
    no_accessibility_adjust=False,
    town_like=None,
    flat_type=None,
    flat_type_like=None,
    flat_model=None,
    flat_model_like=None,
    storey_min=None,
    storey_max=None,
    area_min=None,
    area_max=None,
    lease_min=None,
    lease_max=None,
    transport_cache_dir=None,
    clear_transport_cache=False,
    command=None,
)
exit_code = app.run(args)
print("Exit:", exit_code)

CLI usage (after install):

hdb-valuation-engine --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" --top 5 -v

Usage

hdb-valuation-engine --input <path/to/file.csv> [OPTIONS]

Core options

• --input Path to HDB resale CSV data
• --top Number of results to display (default: 10)
• Logging: -v (INFO) or -vv (DEBUG)

Filters

• Town: --town PUNGGOL (exact), --town-like unggol (partial)
• Flat Type: --flat-type "5 ROOM" (exact), --flat-type-like room (partial)
• Flat Model: --flat-model "Improved" (exact), --flat-model-like improv (partial)
• Storey: --storey-min 7 --storey-max 12
• Area (sqm): --area-min 60 --area-max 120
• Remaining Lease (years): --lease-min 60 --lease-max 95
• Budget (max resale_price): --budget 600000

Grouping (peer comparison)

--group-by town flat_type [flat_model]

Transport Accessibility (MRT via GeoJSON)

• Fast, cached KDTree for nearest MRT exit queries (10k+ rows). Cache saved under .cache_transport/.
• Provide LTA MRT Station Exit GeoJSON to enable accessibility scoring:

# You can fetch a current GeoJSON via the built-in fetcher
hdb-valuation-engine fetch --datasets mrt --mrt-out .data/LTAMRTStationExitGEOJSON.geojson

# Then reference it when running valuations
--mrt-catalog .data/LTAMRTStationExitGEOJSON.geojson

• Excludes LRT strictly via regex ^(BP|S[WE]|P[WE]) and filters names containing LRT as a fallback.
• Adds:
  • Nearest_MRT
  • Dist_m
  • Accessibility_Score = max(0, 10 - 2 * dist_km)
• Analysis-only mode (no adjustment):

--no-accessibility-adjust

Exporting

--output top10.csv --output-format csv            # CSV (default)
--output top10.json --output-format json          # JSON
--output top10.parquet --output-format parquet    # Parquet (falls back to CSV if engine missing)
--export-full                                     # Export all filtered rows instead of Top-N

Quick Usage Examples

0. Cache management subcommand

# Show cache directory
hdb-valuation-engine cache -v

# Clear cache in default location
hdb-valuation-engine cache --clear -v

# Use a custom cache dir
hdb-valuation-engine cache --transport-cache-dir .transport_cache --clear -v

1. Build and cache KDTree from LTA GeoJSON; show Top-10 with adjustment:

hdb-valuation-engine \
  --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" \
  --mrt-catalog ".data/LTAMRTStationExitGEOJSON.geojson" \
  --top 10 -v

2. Use cached KDTree on subsequent runs (faster); analysis-only mode (no price adjustment):

hdb-valuation-engine \
  --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" \
  --mrt-catalog ".data/LTAMRTStationExitGEOJSON.geojson" \
  --no-accessibility-adjust --top 10 -v

3. Custom cache directory and force clear before building:

hdb-valuation-engine \
  --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" \
  --mrt-catalog ".data/LTAMRTStationExitGEOJSON.geojson" \
  --transport-cache-dir ".transport_cache" --clear-transport-cache --top 5 -v

4. CSV catalog path (still supported; auto-excludes LRT lines):

hdb-valuation-engine \
  --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" \
  --mrt-catalog "/path/to/mrt_catalog.csv" --top 5 -v

5. Combine with group-by and export options:

hdb-valuation-engine \
  --input "ResaleFlatPrices/Resale flat prices based on registration date from Jan-2017 onwards.csv" \
  --mrt-catalog ".data/LTAMRTStationExitGEOJSON.geojson" \
  --group-by town flat_type flat_model \
  --export-full --output top.json --output-format json --top 10 -v

Smoke Test Summary

• 2017 onwards: Parsed remaining_lease strings successfully; produced Top-10 Punggol table under budget 600k. Export worked.
• 2012–2014: Inferred remaining lease from lease_commence_date and month; produced Top-10 Punggol table.
• 2000–Feb 2012: Inference path also worked; produced Top-5 for Ang Mo Kio under budget 200k.
• Extended filters and partial matching verified; --output, --export-full, and --output-format worked as expected.

Design & Implementation Notes

• Columns normalized to lowercase with underscores
• Robust z-score handling for zero-variance groups
• Logging across load, feature engineering, scoring, filtering, and export

Release and Tagging

To create a 0.1.0 release and push the tag:

git add -A
git commit -m "chore(release): cut 0.1.0"

git tag -a v0.1.0 -m "Initial PyPI packaging for hdb-valuation-engine"

git push origin main
git push origin v0.1.0

Running Tests

Note: You can fetch data without Make on any platform using the built-in fetch command:

# Fetch all datasets with defaults
hdb-valuation-engine fetch

# Fetch entire resale CSV and MRT exits
hdb-valuation-engine fetch --limit 0

• Recommended: use a virtual environment

python3 -m venv .venv
source .venv/bin/activate  # Windows: .venv\\Scripts\\Activate.ps1
pip install -r requirements.txt
pytest -q

Optional dataset for an extra smoke test

One test is skipped by default unless a local dataset is available. To enable it:

• Create a folder named ResaleFlatPrices at the repository root (same level as tests/ and README.md).
• Place one or more HDB resale CSV files inside that folder, for example:
  • Resale flat prices based on registration date from Jan-2017 onwards.csv

You can fetch a small sample automatically with:

make setup-venv          # one-time environment setup
make fetch-sample-data   # downloads a subset into ./ResaleFlatPrices/

When this folder exists and contains at least one .csv file, the optional smoke test in tests/test_cli_export.py::TestOptionalRealDataset will run. If the folder is missing or empty, the test is skipped with reason:

ResaleFlatPrices folder not present; skipping optional smoke test