Sri Lanka Kandawala Grid
Mar 13,2026

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Introduction

Sri Lanka Kandawala Grid is a historic projected coordinate system based on the Kandawala datum, established during the British colonial period to serve as the foundational mapping framework for the island nation. Developed in the early 20th century, this system employs a transverse Mercator projection to support cadastral surveying, topographic mapping, and engineering projects throughout Sri Lanka. While modern systems like SLD99 / Sri Lanka Grid 1999 (EPSG:5235) have been introduced for contemporary applications, the Kandawala Grid remains essential for interpreting the extensive archive of 20th-century geographic data across the country.

Coordinate System Composition

The Sri Lanka Kandawala Grid is a transverse Mercator projection system based on the Kandawala datum, which utilizes the Everest 1830 ellipsoid . The Kandawala astronomical point serves as the origin of the datum. The projection parameters include a central meridian passing near Pidurutalagala (Sri Lanka's highest peak), with coordinates expressed in meters using easting and northing axes . The defining parameters include a scale factor of 0.9999238, false easting of 200,000 meters, and false northing of -573,991 meters, with the longitude of origin at 80°46.303'E . The system's area of use encompasses all onshore Sri Lanka, with WGS84 bounds approximately between 79.64°E to 81.95°E and 5.86°N to 9.88°N .

Pros

Historical National Standard: Served as the official coordinate reference for topographic mapping and cadastral surveys throughout the British colonial period and post-independence era, creating a unified geospatial framework for the country.
Extensive Archival Compatibility: Underpins the entire corpus of historical maps, land registry documents, and infrastructure plans from the early 20th century, ensuring continuity in land administration and historical research .
Legal and Administrative Foundation: Remains embedded in historical cadastral records and property boundary demarcations, where original surveying documentation continues to form the basis for current land rights.
Transverse Mercator Conformality: As a conformal projection, it preserves local angles and shapes accurately, which is essential for cadastral and engineering applications.

Cons

Non-Geocentric Reference System: Based on the regional Everest 1830 ellipsoid and Kandawala astronomical datum, coordinates are inherently incompatible with modern GNSS measurements and require datum transformation parameters .
Horizontal Position Errors: The original 1930 Kandawala datum likely contains horizontal position errors of a few meters or possibly more, based on later studies that found discrepancies of about 3 meters in some locations compared to new measurements .
Complex Datum Transformation: Converting between Kandawala and WGS84 requires careful parameter selection. Sri Lanka's Survey Department developed their own 7-parameter transformation method, whereas many GPS devices use simpler 3-parameter methods, potentially introducing errors .
Negative False Northing: The false northing of -573,991 meters creates computational complexities and potential for sign errors when processing data .
Parallel System Confusion: The existence of both Kandawala (EPSG:5234) and SLD99 (EPSG:5235) systems, used in parallel, creates potential for misapplication, requiring users to correctly identify which system applies to their specific dataset.

Application Scenario

The Sri Lanka Kandawala Grid is primarily employed in historical data management, cultural heritage preservation, and legacy cadastral administration. It serves as the essential reference system for interpreting and georeferencing the extensive collection of colonial-era topographic maps, historical land registry documents, and early infrastructure plans across Sri Lanka. The system remains crucial for integrating historical agricultural land records, tea plantation surveys, and boundary demarcation documents into modern geospatial analyses, particularly in rural areas where historical surveying records continue to form the basis of current land rights. Professional surveyors, government departments, and researchers working with legacy data must understand both Kandawala and SLD99 systems, as they are used in parallel. The system is indispensable for archaeological research and cultural heritage documentation, enabling researchers to accurately position historical excavation records and legacy site plans within modern GIS environments.