How to Optimize GeoSpatial Queries in MySQL for Addresses Within a Radius?

MySQL within Range Geospatial Query for Maps

Querying geographic data from a large database to display specific locations within a specified range is a common challenge in mapping applications. This question explores how to optimize the retrieval of addresses within a 5-mile radius of a user's given geolocation.

Haversine Formula for Distance Calculation

To determine the distance between two points on the Earth's surface, the Haversine formula is employed. This mathematical formula calculates the great-circle distance, taking into account the Earth's curvature and the latitudes and longitudes of the points.

Query Optimization with Haveline Formula

Leveraging the Haversine formula, the provided MySQL query retrieves only the addresses that fall within the desired range:

$sql = "SELECT *, (3959 * acos( cos( radians(" . $lat . ") ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(" . $lng . ") ) + sin( radians(" . $lat . ") ) * sin( radians( lat ) ) ) ) AS distance FROM your_table HAVING distance < 5";

Parameters and Variables

• $lat**, **$lng: Coordinates of the user's current location.
• lat, lng: Columns in the table containing the coordinates of each address.
• 3959: Earth's radius in miles (convert to 6371 for kilometers).
• distance: Calculated distance between the user's location and each address.

Result

The query outputs a list of addresses with their respective calculated distances. The HAVING clause ensures that only the addresses within the specified 5-mile radius are retrieved, resulting in a more efficient and targeted selection of records. This approach dramatically reduces the amount of data transferred and processed, enhancing the overall performance of the mapping application.

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