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| SIRGAS | |
|---|---|
| Name | SIRGAS |
| Established | 1990s |
| Region | South America, Caribbean |
| Type | Geocentric reference system |
| Coordinates | Geodetic coordinates, Cartesian coordinates |
| Datum realization | ITRF-based regional densification |
| Managing body | SIRGAS Council; national agencies |
SIRGAS SIRGAS is the geocentric reference system widely used across South America and the Caribbean for geodesy, surveying, mapping, and navigation. It provides a consistent horizontal and vertical datum tied to global systems and supports interoperability among national agencies, scientific projects, and infrastructure programs. SIRGAS underpins regional activities ranging from satellite altimetry to cadastral mapping and links national networks to global frameworks.
SIRGAS defines a continental-scale geodetic framework comparable to International Terrestrial Reference Frame, serving countries such as Brazil, Argentina, Colombia, Chile, Peru, Venezuela, Ecuador, Bolivia, Paraguay, Uruguay, Guyana, Suriname, and territories like the Caribbean. It integrates reference points maintained by national institutes including Instituto Brasileiro de Geografia e Estatística, Instituto Geográfico Nacional (Argentina), Instituto Geográfico Agustín Codazzi, and Instituto Geográfico Militar (Chile), aligning them with space geodetic products from missions such as GNSS, GRACE, GOCE, and Jason-3. The system facilitates interoperability with projects like Pan-American Geodetic Project and supports applications in fields tied to NASA, ESA, NOAA, and regional research centers.
The concept emerged during collaborative efforts in the 1990s among institutions including Observatorio Nacional (Brazil), Servicio Geológico Colombiano, and the IGN Spain technical exchanges, influenced by developments in HIPPARCOS and the establishment of the International Earth Rotation and Reference Systems Service. Workshops and symposia organized with participation from UNESCO, IAU, and FIG fostered protocols for homogeneous adoption. Major milestones involved the adoption of realizations linked to successive releases of the International Terrestrial Reference Frame and campaigns that densified stations promoted by agencies like USGS, CONAE, INETER, and universities including Universidad de Chile and Universidad Nacional de La Plata.
Governance combines a continental council with national correspondents and working groups; key stakeholders include national mapping agencies, research institutes, and international bodies such as IUGG and IAG. Administrative coordination has involved committees for reference frames, gravity field, and metadata, drawing expertise from organizations like IGN France, BKG, GFZ Potsdam, and academic groups at MIT, Universidad Complutense de Madrid, and University of Bonn. Funding and operational oversight often engage multilateral entities including Inter-American Development Bank and regional ministries through memoranda with institutions like CONACYT.
SIRGAS defines both a three-dimensional geocentric datum and a geopotential vertical reference consistent with the global geopotential model used by ITRF realizations. The horizontal component provides coordinates in geodetic latitude, longitude, and ellipsoidal height referenced to an ellipsoid compatible with WGS 84 and ITRF epochs. Station coordinates are expressed in Cartesian X, Y, Z for transformation with data from observatories such as Greenwich Observatory and space geodetic networks like IVS and EUREF. The vertical component uses gravimetric and leveling data tied to mean sea level observations from tide gauges maintained by ports such as Port of Callao and Port of Santos and linked to geopotential values from EGM2008 and successive global gravity models.
Realization is achieved through a combination of continuous GNSS networks, repeated relative and absolute gravimetry campaigns, and leveling lines maintained by national agencies and research centers. Continuous stations in networks comparable to CORS and international services provide time series analyzed with software packages developed in collaborations involving GFZ, JPL, and universities such as Ohio State University and ETH Zurich. Seasonal loading, plate tectonics, and crustal deformation are monitored through campaigns comparable to those performed for Andean geodynamics, with adjustments referenced to ITRF epochs. Maintenance procedures include metadata standards, periodic reprocessing of networks, and adoption of models for Earth tides, ocean loading, and atmospheric delays promoted by groups like IERS and IIUGG.
Users range from national cadastral agencies conducting land registration to seismic and volcanic monitoring institutions like INGV, Servicio Sismológico Nacional (Mexico), and regional observatories. SIRGAS supports hydrographic charting by services comparable to Hydrographic Office (Brazil), infrastructure projects such as transcontinental highways, and environmental monitoring programs run by UNEP and CEPAL. It is essential for precision agriculture projects led by universities like Universidad de São Paulo and for telecommunications and surveying firms working with satellite navigation providers including Galileo and GLONASS alongside GPS. Disaster risk management, oil and gas exploration, and urban planning also rely on SIRGAS-consistent coordinates.
SIRGAS aligns with international standards promulgated by IAG, IERS, and ISO technical committees, ensuring compatibility with reference frames such as ITRF and datums like WGS 84. Collaboration with space agencies including ESA, NASA, and Roscosmos supports access to satellite altimetry and gravity missions. Multilateral cooperation involves projects with PAIGH, regional development banks, and academic networks connecting institutions like Universidad de los Andes (Colombia), Pontificia Universidad Católica de Chile, and Universidad Nacional Autónoma de México to maintain harmonized practices and interoperability across boundaries.
Category:Geodesy Category:Geodetic datums Category:Geography of South America