SIRGAS 2000 (South American Datum | EPSG:4674)

GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.

Introduction

**SIRGAS 2000 **is a geocentric reference frame for Central and South America, which aims to define and implement a unified reference frame for Central and South America that is consistent with ITRF. Its ellipsoid adopts GRS 1980, with a major semi-axis of 6378137 meters, an oblateness of 298.257222101, the Greenwich meridian as the prime meridian, and the angle unit is degree. SIRGAS 2000 was established in 2000, consistent with the ITRF2000 framework, with a reference epoch of 2000.0. It is a regional encryption of ITRS in South America, achieved through a network of about 200 continuously operating stations (SIRGAS-CON) throughout Latin America and the Caribbean.

Coordinate System Composition

**ThOrigin: **The center of mass of the earth (the center of the earth) is used as the origin to determine the uniform starting point of the coordinate system.
Coordinate axis

Z axis: points to the direction of the reference pole of the earth at epoch 2000.0, and will adjust with the movement of the earth to avoid residual rotation with the crust.
X axis: points from the origin to the intersection of the Greenwich reference meridian and the equatorial plane at epoch 2000.0.
Y axis: forms a right-handed orthogonal coordinate system with the Z and X axes, just like using the right hand to determine the direction.

Reference ellipsoid parameters

Semi-major axis a: 6378137 meters, which is the maximum radius of the ellipsoid in the equatorial direction.
Flattening f: 1/298.257222101, determines the degree of flatness of the ellipsoid.
Gravitational constant GM: 3.986004418×10¹⁴ cubic meters per second squared, reflecting the characteristics of the earth’s gravitational field.
**Angular velocity of rotation ω: **7.292115×10⁻⁵ radians per second, reflecting the speed of the Earth’s rotation.

Coordinate frame and epoch

Coordinate frame: ITRF97 is used, which is an internationally unified coordinate reference standard.
Reference epoch: 2000.0, indicating that the coordinates are the instantaneous coordinates of this epoch.

Pros

Strong regional adaptability: SIRGAS 2000, as a unified geocentric reference frame for Central and South America, is consistent with ITRF and can adapt well to the geographical features of Central and South America, providing accurate spatial reference for geographic information applications in the region and meeting local geodetic and geodynamic research needs.
High accuracy: Through a large amount of GPS observation station data and complex processing, SIRGAS 2000 has high coordinate accuracy and can provide reliable geographic coordinate support for engineering construction, resource exploration, etc. in Central and South America.
Dynamic update: SIRGAS 2000 will be updated and maintained over time and with new observation data to ensure its consistency with the actual movement of the earth, providing a continuous and accurate spatial benchmark for geographic information applications in Central and South America.

Cons

Poor global compatibility: SIRGAS 2000 is mainly aimed at Central and South America. When used globally, there may be complexity and loss of accuracy in coordinate system conversion with other regions, which limits its use in multinational projects or global geographic information applications.
Complex data processing: Since SIRGAS 2000 data processing involves a large amount of GPS observation data and complex algorithms, data processing and analysis are difficult for general users and require professional technicians and software support.
High construction cost: Establishing and maintaining the GPS observation station network and data processing center required by SIRGAS 2000 requires a lot of capital and technical investment, which may be difficult for some economically underdeveloped countries in Central and South America.

Application Scenario

SIRGAS 2000 is suitable for geodesy, geodynamic research, engineering construction, resource exploration and other fields in Central and South America that require high-precision geographic coordinates. It can provide these fields with a geocentric reference frame consistent with ITRF and meet the localized geographic information needs of Central and South America.

Example

Scope of application of SIRGAS 2000.

SIRGAS 2000.