Grids & Datums Co-operative Republic of Guyana α The region known as Guiana or Guayana is on rectorate of Colonial Surveys (DOS) observed Hondo o = 40° 22' 45.96" (PE&RS, December the northeastern coast of South America. It some astro fixes, assessed the existing Lands 2000). La Canoa is about 657 km from is comprised of the former British Guiana, and Mines Department and Bauxite Company Georgetown Lighthouse, and the Zanderij now Guyana, the former Netherlands Guiana, work and agreed with them on an adjustment Datum origin in Suriname (PE&RS, March now Suriname (PE&RS, March 2002), and strategy to produce a unified set of coordi- 2002) is about 361 km from Georgetown Light- French Guiana. Originally inhabited by the nates from the disparate (albeit high quality) house. Surinen Indians, the coast was probably traverses and astro fixes. The method was to Of all of the borders of Guyana, only the sighted by Christopher Columbus in 1498 and accept certain fixes and traverses and to ad- Brazil-Guyana boundary appears to be cur- by Ojeda and Vespucci in 1499. Vicente Yáñez just weaker ones to fit; there was not a single rently stable and uncontested. Reading the de Pinzón in 1500 was the first to sail close datum station. The system adopted was the history of the region is a veritable jumble of along the shore. He entered some of the riv- British Guyana Grid on the Transverse squabbles among the European powers over ers, and the Oyapock River was at first called Mercator projection referenced to the Inter- centuries that were reflected in the whole of the Yáñez Pinzón River by the Dutch, and national ellipsoid where a = 6,378, 388 and the Guianas by the British, Dutch, French, ϕ Venezuelan, and Portuguese. Of late, there later called the Vincent Pinzón River by the 1/f = 297. Latitude of Origin, o = equator, French. Initially, both Spanish and Portuguese λ has even been some gunboat diplomacy be- Central Meridian, o = 59º West of Green- mariners avoided the coast between the wich, False Easting = 900,000 feet, False tween Guyana and Suriname over the min- Oyapock and Orinoco rivers. In 1597-1598, a Northing = nil, and the Central Scale Factor, eral (oil and gas) resources of the offshore Dutch expedition examined the river mouths continental shelf. Some of the diplomatic po- mo = 0.99975. The U.S. Inter American Geo- from the Amazon to the Orinoco. This started detic Survey observed a Hiran trilateration sition papers are available over the internet, a series of colonies settled initially by the between Venezuela and Brazil in the late and make for some fascinating reading about Dutch, then by the French and the English 1960s. DOS decided to use that as the basis the history of the border negotiations. that all attempted to simultaneously fight the of a new national network for Guyana and, in The latest transformation parameters avail- climate, the jungle, and the Indians. The coun- 1971, computed an adjustment based on the able from NIMA regarding the shift from the try was eventually ceded to Great Britain by 1970 Aerodist values of Hiran stations PSAD56 to the WGS84 Datum in Guyana are ∆ ∆ the Dutch in 1814, and it became the British Atkinson and Rose. DOS called the datum X = –298 m ±6 m, Y = +159 m ±14 m, ∆ Guiana Crown Colony in 1831. Guyana Provisional South American 1956. The Inter- Z = –369 m ± 6m, and this is based on a achieved independence in 1966, it became a national ellipsoid was retained but the UTM solution of nine points in Guyana. Early in republic in 1970, and it adopted a new con- Grid replaced the British Guyana Grid. That 1997, the U.S. National Geodetic Survey pub- stitution in 1980. system was used on all subsequent DOS lished NAD83 coordinates of several local Slightly smaller than Idaho, Guyana bor- mapping. Note that the 1978 readjustment of marks in Guyana that were observed by NGS ders Brazil (1,119 km), Suriname (600 km), the Aerodist trilateration by Matti Jaakkola personnel. Being consistent in the NGS and Venezuela (743 km). Its coastline on the was not used by DOS. The Royal Engineers “policy” that I consider to be ill conceived Atlantic Ocean is 459 km long; it claims a and DOS did a lot of Doppler work, DOS to and wasteful of U.S. taxpayer funds, no local territorial sea of 12 nautical miles, and it claims control the aerial photography for its 1:50,000 datum coordinates were researched by NGS mineral rights to 200 nautical miles or to the and large-scale coastal zone map series.” personnel nor published in the NGS data outer edge of the continental margin. Guyana According to John W. Hager, now retired sheets. Considering the expenses of a geo- terrain is mostly rolling highlands with a low, from NIMA, the DOS astro fix at Georgetown detic expedition, consistently not having “suf- swampy coastal plain and a savanna in the Lighthouse was published as a mean of deter- ficient funds” to research a local survey of- fice nor occupy original datum origin points south. The lowest point is the Atlantic Ocean minations observed in 1926 and 1951 where and the highest point is Mount Roraima (2,835 Φ Λ is a specious argument. Let’s try harder, NGS! o = 6º 49' 31.12" N and o = 58º 09' 52.76" m) in the Pakaraima Range along the Venezu- West of Greenwich. The International ellip- Ô ela-Brazil border. soid was used at the time, as published in the Cliff Mugnier teaches Surveying, Geodesy, According to Russell Fox of the Ordnance Guyana Trig List, 3rd edition, 1967. Hager went and Photogrammetry at Louisiana State Uni- Survey’s International Library, “In the first on to say, “Five stations were established in versity. He is the Chief of Geodesy at LSU’s half of the 20th century the Lands and Mines Guyana as part of the Hiran net from the Car- Center for GeoInformatics (Dept. of Civil and Department had observed some high-order ibbean to Brazil. Only station Eagle was held Environmental Engineering), and his geodetic astro fixes and traverses in the coastal zone fixed in the Terra Surveys Limited of Canada research is mainly in the subsidence of Loui- and along the main river valleys leading to network established about 1968. The posi- siana and in Grids and Datums of the world. the mining areas in the interior of the north- tion of Eagle is on the Provisional South He is a Board-certified Photogrammetrist and ern part of British Guyana. There were also a American Datum of 1956 where, for Aerodist Mapping Scientist (GIS/LIS), and he has ex- few railway traverses by other entities, such Station Eagle, ϕ = 5º 13' 23.6660” N and tensive experience in the practice of Foren- as the Bauxite Company. The only triangula- λ = 59º 06' 10.0549" W.” sic Photogrammetry. tion appears to have been the British Guyana- The origin of the Provisional South Ameri- The contents of this column reflect the views of the Brazil boundary survey of the 1930s. The ab- can Datum of 1956 (PSAD56) is at La Canoa, author, who is responsible for the facts and accuracy of the data presented herein. The contents do not neces- sence of a national triangulation network re- Anzoátegui Province, Venezuela where sarily reflect the official views or policies of the Ameri- sulted from logistical, topographical and eco- Φ = 08° 34’17.170" N, Λ = 63° 51' 34.880" W, can Society for Photogrammetry and Remote Sensing o o and/or the Louisiana State University Center for GeoInfor- nomic limitations. In the early 1950s the Di- and the defining azimuth to station Pozo matics (C4G). PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING April 2003 321.