Crime Patterns Webmap

Live Webmap¶

For a better experience, click here.

Project Overview¶

Crime Patterns is a city-focused analytics webmap that makes it easy to explore reported crime incidents across time, location, and category. The frontend provides interactive basemaps and filters, while the backend performs server-side aggregation to produce performant heatmap layers and summary statistics.

Why It Matters¶

• Situational awareness: Highlights hotspot clusters and temporal shifts for public safety insights.

• Exploratory analysis: Enables quick filtering by city, date range, and occurrence category.

• Performance at scale: Heatmap aggregation reduces client load on large datasets.

• Decision support: Summaries and time-series breakdowns help compare periods and categories.

Key Features¶

• Interactive map with multiple basemaps and layers.

• Server-side heatmap aggregation for large datasets.

• Dynamic filters for city, date range, and occurrence category.

• Summary stats and top groups/types for quick context.

• Point layer with tooltips for incident-level inspection.

Architecture¶

Frontend

• Leaflet map UI with filters, heatmap, and point layers.

• Bootstrap and jQuery for layout and interactions.

• UI widgets and plugins for enhanced map controls.

Backend

• PHP endpoints that return GeoJSON, aggregated heat points, and stats.

• Token-based write security (configurable, if enabled).

Database

• PostgreSQL + PostGIS with a crimes_master table containing geometry and attributes.

Data Model Requirements¶

Key fields used in the app:

• crime_database_id (integer)

• date_reported (date)

• reported_date (varchar)

• reported_day (integer)

• reported_month (integer)

• reported_year (varchar)

• occurrence_category (varchar)

• occurrence_group (varchar)

• occurrence_type_group (varchar)

• intersection (varchar)

• objectid (integer)

• province (text)

• city_name (text)

• geom (geometry, MultiPoint, SRID 4326)

Recommended indexes:

CREATE INDEX crimes_master_geom_gix ON crimes_master USING GIST (geom);
CREATE INDEX crimes_master_date_idx ON crimes_master (date_reported);
CREATE INDEX crimes_master_city_idx ON crimes_master (city_name);

API Endpoints¶

All endpoints accept POST parameters.

• api_calls/load_crimes.php
  Returns GeoJSON points for the selected filters.

• api_calls/heat_crimes.php
  Returns aggregated heatmap points (optional grid_size).

• api_calls/stats_crimes.php
  Returns summary stats and time-series breakdowns.

• api_calls/cities.php
  Returns available cities.

• api_calls/categories.php
  Returns categories for a selected city.

• api_calls/latest_date.php
  Returns the latest report date by city.

Configuration¶

Create a config file or use environment variables:

/Applications/XAMPP/xamppfiles/htdocs/config/db.php

Supported environment variables:

• WEBMAP_DSN

• WEBMAP_DB_USER

• WEBMAP_DB_PASS

• WEBMAP_WRITE_TOKEN

Local Run (XAMPP)¶

1. Start Apache (and PostgreSQL if local).

2. Place the project in your web root.

3. Open the site in a browser and test the filters.

Suggested Improvements¶

• Add cached aggregation for frequently queried views.

• Replace the time-series list with a charting library (ECharts/Chart.js).

• Add occurrence group/type filters and saved filter presets.

• Explore vector tiles or hexbin aggregation for smoother zoom behavior.