The available geographic coordinate systems.
| Constant | Value | Description |
|---|---|---|
| esriSRGeoCS_Airy1830 | 4001 | Airy 1830. |
| esriSRGeoCS_ModifiedAiry | 4002 | Airy modified. |
| esriSRGeoCS_ATS1977 | 4122 | Average Terrestrial System 1977. |
| esriSRGeoCS_Australian | 4003 | Australian National. |
| esriSRGeoCS_Bessel1841 | 4004 | Bessel 1841. |
| esriSRGeoCS_ModifiedBessel | 4005 | Bessel modified. |
| esriSRGeoCS_BesselNamibia | 4006 | Bessel Namibia. |
| esriSRGeoCS_Clarke1858 | 4007 | Clarke 1858. |
| esriSRGeoCS_Clarke1866 | 4008 | Clarke 1866. |
| esriSRGeoCS_Clarke1866Michigan | 4009 | Clarke 1866 Michigan. |
| esriSRGeoCS_Clarke1880 | 4034 | Clarke 1880. |
| esriSRGeoCS_Clarke1880Arc | 4013 | Clarke 1880 (Arc). |
| esriSRGeoCS_Clarke1880Benoit | 4010 | Clarke 1880 (Benoit). |
| esriSRGeoCS_Clarke1880IGN | 4011 | Clarke 1880 (IGN). |
| esriSRGeoCS_Clarke1880RGS | 4012 | Clarke 1880 (RGS). |
| esriSRGeoCS_Clarke1880SGA | 4014 | Clarke 1880 (SGA). |
| esriSRGeoCS_Everest1830 | 4042 | Everest 1830. |
| esriSRGeoCS_Everest1962 | 4044 | Everest (definition 1962). |
| esriSRGeoCS_Everest1967 | 4016 | Everest (definition 1967). |
| esriSRGeoCS_Everest1975 | 4045 | Everest (definition 1975). |
| esriSRGeoCS_ModifiedEverest | 4018 | Everest modified. |
| esriSRGeoCS_GEM10C | 4031 | GEM gravity potential model. |
| esriSRGeoCS_GRS1967 | 4036 | GRS 1967. |
| esriSRGeoCS_GRS1980 | 4019 | GRS 1980. |
| esriSRGeoCS_Helmert1906 | 4020 | Helmert 1906. |
| esriSRGeoCS_Indonesian | 4021 | Indonesian National. |
| esriSRGeoCS_International1924 | 4022 | International 1927. |
| esriSRGeoCS_International1967 | 104023 | International 1967. |
| esriSRGeoCS_Krasovsky1940 | 4024 | Krasovsky 1940. |
| esriSRGeoCS_NWL9D | 4025 | Transit precise ephemeris. |
| esriSRGeoCS_OSU1986F | 4032 | OSU 1986 geoidal model. |
| esriSRGeoCS_OSU1991A | 4033 | OSU 1991 geoidal model. |
| esriSRGeoCS_Plessis1817 | 4027 | Plessis 1817. |
| esriSRGeoCS_Authalicsphere | 4035 | Authalic sphere. |
| esriSRGeoCS_Struve1860 | 4028 | Struve 1860. |
| esriSRGeoCS_WarOffice | 4029 | War Office. |
| esriSRGeoCS_WGS1966 | 4760 | WGS 1966. |
| esriSRGeoCS_Fischer1960 | 37002 | Fischer 1960. |
| esriSRGeoCS_Fischer1968 | 37003 | Fischer 1968. |
| esriSRGeoCS_ModifiedFischer | 37004 | Fischer modified. |
| esriSRGeoCS_Hough1960 | 37005 | Hough 1960. |
| esriSRGeoCS_ModifiedEverest1969 | 37006 | Everest modified 1969. |
| esriSRGeoCS_Walbeck | 37007 | Walbeck. |
| esriSRGeoCS_AuthalicsphereARCINFO | 37008 | Authalic sphere (ARC/INFO). |
| esriSRGeoCS_AssumedGeographic1 | 104000 | Assumed Geographic 1. |
| esriSRGeoCS_Abidjan1987 | 4143 | Abidjan 1987. |
| esriSRGeoCS_Adindan | 4201 | Adindan. |
| esriSRGeoCS_Afgooye | 4205 | Afgooye. |
| esriSRGeoCS_Agadez | 4206 | Agadez. |
| esriSRGeoCS_AGD1966 | 4202 | Australian Geodetic Datum 1966. |
| esriSRGeoCS_AGD1984 | 4203 | Australian Geodetic Datum 1984. |
| esriSRGeoCS_AinElAbd1970 | 4204 | Ain el Abd 1970. |
| esriSRGeoCS_Amersfoort | 4289 | Amersfoort. |
| esriSRGeoCS_Aratu | 4208 | Aratu. |
| esriSRGeoCS_Arc1950 | 4209 | Arc 1950. |
| esriSRGeoCS_Arc1960 | 4210 | Arc 1960. |
| esriSRGeoCS_ATFParis | 4901 | ATF (Paris). |
| esriSRGeoCS_Barbados1938 | 4212 | Barbados 1938. |
| esriSRGeoCS_Batavia | 4211 | Batavia. |
| esriSRGeoCS_BataviaJakarta | 4813 | Batavia (Jakarta). |
| esriSRGeoCS_Beduaram | 4213 | Beduaram. |
| esriSRGeoCS_Beijing1954 | 4214 | Beijing 1954. |
| esriSRGeoCS_Belge1950 | 4215 | Reseau National Belge 1950. |
| esriSRGeoCS_Belge1950Brussels | 4809 | Belge 1950 (Brussels). |
| esriSRGeoCS_Belge1972 | 4313 | Reseau National Belge 1972. |
| esriSRGeoCS_Bermuda1957 | 4216 | Bermuda 1957. |
| esriSRGeoCS_Bern1898Bern | 4801 | Bern 1898 (Bern). |
| esriSRGeoCS_Bern1938 | 4306 | Bern 1938. |
| esriSRGeoCS_Bogota | 4218 | Bogota. |
| esriSRGeoCS_BogotaBogota | 4802 | Bogota (Bogota). |
| esriSRGeoCS_BukitRimpah | 4219 | Bukit Rimpah. |
| esriSRGeoCS_Camacupa | 4220 | Camacupa. |
| esriSRGeoCS_CampoInchauspe | 4221 | Campo Inchauspe. |
| esriSRGeoCS_Cape | 4222 | Cape. |
| esriSRGeoCS_Carthage | 4223 | Carthage. |
| esriSRGeoCS_CarthageDegrees | 4223 | Carthage (degrees). |
| esriSRGeoCS_CH1903 | 4149 | CH 1903. |
| esriSRGeoCS_CH1903Plus | 4150 | CH 1903+. |
| esriSRGeoCS_CHTRF1995 | 4151 | Chua. |
| esriSRGeoCS_CHUA | 4224 | Chua. |
| esriSRGeoCS_Conakry1905 | 4315 | Conakry 1905. |
| esriSRGeoCS_CorregoAlegre | 4225 | Corrego Alegre. |
| esriSRGeoCS_CoteDIvoire | 4226 | Cote d'Ivoire. |
| esriSRGeoCS_Datum73 | 4274 | Datum 73. |
| esriSRGeoCS_DealulPiscului1933 | 4316 | Dealul Piscului 1933 (Romania). |
| esriSRGeoCS_DealulPiscului1970 | 4317 | Dealul Piscului 1970 (Romania). |
| esriSRGeoCS_DeirezZor | 4227 | Deir ez Zor. |
| esriSRGeoCS_DHDN | 4314 | Deutsche Hauptdreiecksnetz. |
| esriSRGeoCS_Douala | 4228 | Douala. |
| esriSRGeoCS_EuropeanDatum1950 | 4230 | European Datum 1950. |
| esriSRGeoCS_EuropeanDatum1950ED77 | 4154 | European Datum 1950 (ED77). |
| esriSRGeoCS_EuropeanDatum1987 | 4231 | European Datum 1987. |
| esriSRGeoCS_Egypt1907 | 4229 | Egypt 1907. |
| esriSRGeoCS_ETRF1989 | 104258 | European Terrestrial Ref. Frame 1989. |
| esriSRGeoCS_Fahud | 4232 | Fahud. |
| esriSRGeoCS_Gandajika1970 | 4233 | Gandajika 1970. |
| esriSRGeoCS_Garoua | 4234 | Garoua. |
| esriSRGeoCS_GDA1994 | 4283 | Geocentric Datum of Australia 1994. |
| esriSRGeoCS_GGRS1987 | 4121 | Greek Geodetic Ref. System 1987. |
| esriSRGeoCS_Greek | 4120 | Greek. |
| esriSRGeoCS_GreekAthens | 4815 | Greek (Athens). |
| esriSRGeoCS_GuyaneFrancaise | 4235 | Guyane Francaise. |
| esriSRGeoCS_Hanoi1972 | 4147 | Hanoi 1972. |
| esriSRGeoCS_Hartebeesthoek1994 | 4148 | Hartebeesthoek 1994. |
| esriSRGeoCS_HeratNorth | 4255 | Herat North. |
| esriSRGeoCS_HitoXVIII1963 | 4254 | Hito XVIII 1963. |
| esriSRGeoCS_HuTzuShan | 4236 | Hu Tzu Shan. |
| esriSRGeoCS_Hungarian1972 | 4237 | Hungarian Datum 1972. |
| esriSRGeoCS_Indian1954 | 4239 | Indian 1954. |
| esriSRGeoCS_Indian1975 | 4240 | Indian 1975. |
| esriSRGeoCS_Indonesian1974 | 4238 | Indonesian Datum 1974. |
| esriSRGeoCS_Israel | 4141 | Israel. |
| esriSRGeoCS_Jamaica1875 | 4241 | Jamaica 1875. |
| esriSRGeoCS_Jamaica1969 | 4242 | Jamaica 1969. |
| esriSRGeoCS_Kalianpur1880 | 4243 | Kalianpur 1880. |
| esriSRGeoCS_Kalianpur1937 | 4144 | Kalianpur 1937. |
| esriSRGeoCS_Kalianpur1962 | 4145 | Kalianpur 1962. |
| esriSRGeoCS_Kalianpur1975 | 4146 | Kalianpur 1975. |
| esriSRGeoCS_Kandawala | 4244 | Kandawala. |
| esriSRGeoCS_Kertau | 4245 | Kertau. |
| esriSRGeoCS_KKJ | 4123 | Kartastokoordinaattijarjestelma. |
| esriSRGeoCS_KOC | 4246 | Kuwait Oil Company. |
| esriSRGeoCS_KUDAMS | 4319 | Kuwait Utility. |
| esriSRGeoCS_LaCanoa | 4247 | La Canoa. |
| esriSRGeoCS_Lake | 4249 | Lake. |
| esriSRGeoCS_Leigon | 4250 | Leigon. |
| esriSRGeoCS_Liberia1964 | 4251 | Liberia 1964. |
| esriSRGeoCS_Lisbon | 4207 | Lisbon. |
| esriSRGeoCS_LisbonLisbon | 4803 | Lisbon (Lisbon). |
| esriSRGeoCS_Locodjo1965 | 4142 | Locodjo 1965. |
| esriSRGeoCS_LomaQuintana | 4288 | Loma Quintana. |
| esriSRGeoCS_Lome | 4252 | Lome. |
| esriSRGeoCS_Luzon1911 | 4253 | Luzon 1911. |
| esriSRGeoCS_Mahe1971 | 4256 | Mahe 1971. |
| esriSRGeoCS_Makassar | 4257 | Makassar. |
| esriSRGeoCS_MakassarJakarta | 4804 | Makassar (Jakarta). |
| esriSRGeoCS_Malongo1987 | 4259 | Malongo 1987. |
| esriSRGeoCS_Manoca | 4260 | Manoca. |
| esriSRGeoCS_Massawa | 4262 | Massawa. |
| esriSRGeoCS_Merchich | 4261 | Merchich. |
| esriSRGeoCS_MerchichDegree | 104261 | Merchich (Degree). |
| esriSRGeoCS_MGI | 4312 | Militar-Geographische Institut. |
| esriSRGeoCS_MGIFerro | 4805 | MGI (Ferro). |
| esriSRGeoCS_Mhast | 4264 | Mhast. |
| esriSRGeoCS_Minna | 4263 | Minna. |
| esriSRGeoCS_MonteMario | 4265 | Monte Mario. |
| esriSRGeoCS_MonteMarioRome | 4806 | Monte Mario (Rome). |
| esriSRGeoCS_MPoraloko | 4266 | M'poraloko. |
| esriSRGeoCS_NADMichigan | 4268 | NAD Michigan. |
| esriSRGeoCS_NAD1927 | 4267 | North American Datum 1927. |
| esriSRGeoCS_NAD1983 | 4269 | North American Datum 1983. |
| esriSRGeoCS_NAD1983HARN | 4152 | North American Datum 1983 (HARN). |
| esriSRGeoCS_NAD1983CSRS98 | 4617 | NAD 1983 (Canadian SRS 1998). |
| esriSRGeoCS_Nahrwan1967 | 4270 | Nahrwan 1967. |
| esriSRGeoCS_Naparima1972 | 4271 | Naparima 1972. |
| esriSRGeoCS_NorddeGuerreParis | 4902 | Nord de Guerre (Paris). |
| esriSRGeoCS_NGN | 4318 | National Geodetic Network (Kuwait). |
| esriSRGeoCS_NGO1948 | 4273 | NGO 1948. |
| esriSRGeoCS_NGO1948Oslo | 4817 | NGO 1948 (Oslo). |
| esriSRGeoCS_NordSahara1959 | 4307 | Nord Sahara 1959. |
| esriSRGeoCS_NSWC9Z_2 | 4276 | NSWC 9Z-2. |
| esriSRGeoCS_NTF | 4275 | Nouvelle Triangulation Francaise. |
| esriSRGeoCS_NTFParis | 4807 | NTF (Paris). |
| esriSRGeoCS_NZGD1949 | 4272 | New Zealand Geodetic Datum 1949. |
| esriSRGeoCS_OSSN1980 | 4279 | OS (SN) 1980. |
| esriSRGeoCS_OSGB1936 | 4277 | OSGB 1936. |
| esriSRGeoCS_OSGB1970SN | 4278 | OSGB 1970 (SN). |
| esriSRGeoCS_Padang1884 | 4280 | Padang 1884. |
| esriSRGeoCS_Padang1884Jakarta | 4808 | Padang 1884 (Jakarta). |
| esriSRGeoCS_Palestine1923 | 4281 | Palestine 1923. |
| esriSRGeoCS_PointeNoire | 4282 | Pointe Noire. |
| esriSRGeoCS_PSAD1956 | 4248 | Provisional South American Datum 1956. |
| esriSRGeoCS_Pulkovo1942 | 4284 | Pulkovo 1942. |
| esriSRGeoCS_Pulkovo1995 | 4200 | Pulkovo 1995. |
| esriSRGeoCS_Qatar | 4285 | Qatar. |
| esriSRGeoCS_Qatar1948 | 4286 | Qatar 1948. |
| esriSRGeoCS_Qornoq | 4287 | Qornoq. |
| esriSRGeoCS_Rassadiran | 4153 | Rassadiran. |
| esriSRGeoCS_RT38 | 4308 | RT38. |
| esriSRGeoCS_RT38Stockholm | 4814 | RT38 (Stockholm). |
| esriSRGeoCS_SAD1969 | 4618 | South American Datum 1969. |
| esriSRGeoCS_SapperHill1943 | 4292 | Sapper Hill 1943. |
| esriSRGeoCS_Schwarzeck | 4293 | Schwarzeck. |
| esriSRGeoCS_Segora | 4294 | Segora. |
| esriSRGeoCS_Serindung | 4295 | Serindung. |
| esriSRGeoCS_Sudan | 4296 | Sudan. |
| esriSRGeoCS_Tananarive1925 | 4297 | Tananarive 1925. |
| esriSRGeoCS_Tananarive1925Paris | 4810 | Tananarive 1925 (Paris). |
| esriSRGeoCS_Timbalai1948 | 4298 | Timbalai 1948. |
| esriSRGeoCS_TM65 | 4299 | TM65. |
| esriSRGeoCS_TM75 | 4300 | TM75. |
| esriSRGeoCS_Tokyo | 4301 | Tokyo. |
| esriSRGeoCS_Trinidad1903 | 4302 | Trinidad 1903. |
| esriSRGeoCS_TrucialCoast1948 | 4303 | Trucial Coast 1948. |
| esriSRGeoCS_Voirol1875 | 4304 | Voirol 1875. |
| esriSRGeoCS_Voirol1875Degree | 4304 | Voirol 1875 (Degree). |
| esriSRGeoCS_Voirol1875Paris | 4811 | Voirol 1875 (Paris). |
| esriSRGeoCS_VoirolUnifie1960 | 4305 | Voirol Unifie 1960. |
| esriSRGeoCS_VoirolUnifie1960Degree | 104305 | Voirol Unifie 1960 (Degree). |
| esriSRGeoCS_VoirolUnifie1960Paris | 4812 | Voirol Unifie 1960 (Paris). |
| esriSRGeoCS_WGS1972 | 4322 | WGS 1972. |
| esriSRGeoCS_WGS1972BE | 4324 | WGS 1972 Transit Broadcast Ephemer. |
| esriSRGeoCS_WGS1984 | 4326 | WGS 1984. |
| esriSRGeoCS_Yacare | 4309 | Yacare. |
| esriSRGeoCS_Yoff | 4310 | Yoff. |
| esriSRGeoCS_Zanderij | 4311 | Zanderij. |
| esriSRGeoCS_CarthageParis | 4816 | Carthage (Paris). |
| esriSRGeoCS_FD1958 | 4132 | Final Datum 1958. |
| esriSRGeoCS_LKS1994 | 4669 | LKS 1994. |
| esriSRGeoCS_Madrid1870Madrid | 4903 | Madrid 1870 (Madrid). |
| esriSRGeoCS_Madzansua | 4128 | Madzansua. |
| esriSRGeoCS_Moznet | 4130 | Moznet. |
| esriSRGeoCS_Observatario | 4129 | Observatario. |
| esriSRGeoCS_RT90 | 4124 | RT 1990. |
| esriSRGeoCS_Samboja | 4125 | Samboja. |
| esriSRGeoCS_Tete | 4127 | Tete. |
| esriSRGeoCS_Estonia1992 | 4133 | Estonia 1992. |
| esriSRGeoCS_PDO1993 | 4134 | PDO Survey Datum 1993. |
| esriSRGeoCS_Anguilla1957 | 4600 | Anguilla 1957. |
| esriSRGeoCS_Antigua1943 | 4601 | Antigua Astro 1943. |
| esriSRGeoCS_Dominica1945 | 4602 | Dominica 1945. |
| esriSRGeoCS_Grenada1953 | 4603 | Grenada 1953. |
| esriSRGeoCS_StKitts1955 | 4605 | St. Kitts 1955. |
| esriSRGeoCS_StLucia1955 | 4606 | St. Lucia 1955. |
| esriSRGeoCS_StVincent1945 | 4607 | St. Vincent 1945. |
| esriSRGeoCS_NAD1927Def1976 | 4608 | NAD 1927 Definition 1976. |
| esriSRGeoCS_NAD1927CGQ77 | 4609 | NAD 1927 CGQ77. |
| esriSRGeoCS_StGeorgeIsland | 4138 | St. George Island. |
| esriSRGeoCS_StLawrenceIsland | 4136 | St. Lawrence Island. |
| esriSRGeoCS_StPaulIsland | 4137 | St. Paul Island. |
| esriSRGeoCS_European1979 | 4668 | European 1979. |
| esriSRGeoCS_EverestBangladesh | 37202 | Everest - Bangladesh. |
| esriSRGeoCS_EverestIndiaNepal | 37203 | Everest - India and Nepal. |
| esriSRGeoCS_Hjorsey1955 | 4658 | Hjorsey 1955. |
| esriSRGeoCS_HongKong1963 | 4738 | Hong Kong 1963. |
| esriSRGeoCS_Oman | 37206 | Oman. |
| esriSRGeoCS_SouthAsiaSingapore | 37207 | South Asia Singapore. |
| esriSRGeoCS_Ayabelle | 4713 | Ayabelle Lighthouse. |
| esriSRGeoCS_Bissau | 4165 | Bissau. |
| esriSRGeoCS_Dabola | 4155 | Dabola. |
| esriSRGeoCS_Point58 | 4620 | Point 58. |
| esriSRGeoCS_BeaconE1945 | 4709 | Astro Beacon E 1945. |
| esriSRGeoCS_TernIsland1961 | 4707 | Tern Island Astro 1961. |
| esriSRGeoCS_Astro1952 | 4711 | Astronomical Station 1952. |
| esriSRGeoCS_BellevueIGN | 4714 | Bellevue IGN. |
| esriSRGeoCS_Canton1966 | 4716 | Canton Astro 1966. |
| esriSRGeoCS_ChathamIsland1971 | 4672 | Chatham Island Astro 1971. |
| esriSRGeoCS_DOS1968 | 37218 | DOS 1968. |
| esriSRGeoCS_EasterIsland1967 | 4719 | Easter Island 1967. |
| esriSRGeoCS_Guam1963 | 4675 | Guam 1963. |
| esriSRGeoCS_GUX1 | 37221 | GUX 1 Astro. |
| esriSRGeoCS_JohnstonIsland1961 | 4725 | Johnston Island 1961. |
| esriSRGeoCS_Kusaie1951 | 4735 | Kusaie Astro 1951. |
| esriSRGeoCS_Midway1961 | 4727 | Midway Astro 1961. |
| esriSRGeoCS_OldHawaiian | 4135 | Old Hawaiian. |
| esriSRGeoCS_Pitcairn1967 | 4729 | Pitcairn Astro 1967. |
| esriSRGeoCS_SantoDOS1965 | 4730 | Santo DOS 1965. |
| esriSRGeoCS_VitiLevu1916 | 4731 | Viti Levu 1916. |
| esriSRGeoCS_WakeEniwetok1960 | 4732 | Wake-Eniwetok 1960. |
| esriSRGeoCS_WakeIsland1952 | 4733 | Wake Island Astro 1952. |
| esriSRGeoCS_Anna1_1965 | 4708 | Anna 1 Astro 1965. |
| esriSRGeoCS_Gan1970 | 4684 | Gan 1970. |
| esriSRGeoCS_ISTS073_1969 | 4724 | ISTS 073 Astro 1969. |
| esriSRGeoCS_KerguelenIsland1949 | 4698 | Kerguelen Island 1949. |
| esriSRGeoCS_Reunion | 4626 | Reunion. |
| esriSRGeoCS_AscensionIsland1958 | 4712 | Ascension Island 1958. |
| esriSRGeoCS_DOS71_4 | 4710 | Astro DOS 71/4. |
| esriSRGeoCS_CapeCanaveral | 4717 | Cape Canaveral. |
| esriSRGeoCS_FortThomas1955 | 37240 | Fort Thomas 1955. |
| esriSRGeoCS_Graciosa1948 | 37241 | Graciosa Base SW 1948. |
| esriSRGeoCS_ISTS061_1968 | 4722 | ISTS 061 Astro 1968. |
| esriSRGeoCS_LC5_1961 | 37243 | L.C. 5 Astro 1961. |
| esriSRGeoCS_Montserrat1958 | 4604 | Montserrat Astro 1958. |
| esriSRGeoCS_ObservMeteor1939 | 37245 | Observ. Meteorologico 1939. |
| esriSRGeoCS_PicodeLasNieves | 4728 | Pico de Las Nieves. |
| esriSRGeoCS_PortoSanto1936 | 4615 | Porto Santo 1936. |
| esriSRGeoCS_PuertoRico | 4139 | Puerto Rico. |
| esriSRGeoCS_SaoBraz | 37249 | Sao Braz. |
| esriSRGeoCS_SelvagemGrande1938 | 4616 | Selvagem Grande 1938. |
| esriSRGeoCS_Tristan1968 | 4734 | Tristan Astro 1968. |
| esriSRGeoCS_Samoa1962 | 4169 | American Samoa 1962. |
| esriSRGeoCS_CampArea | 4715 | Camp Area Astro. |
| esriSRGeoCS_DeceptionIsland | 4736 | Deception Island. |
| esriSRGeoCS_GunungSegara | 4613 | Gunung Segara. |
| esriSRGeoCS_Indian1960 | 4131 | Indian 1960. |
| esriSRGeoCS_S_42Hungary | 37257 | S-42 Hungary. |
| esriSRGeoCS_S_JTSK | 4156 | S-JTSK. |
| esriSRGeoCS_AlaskanIslands | 37260 | Alaskan Islands. |
Product Availability
Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.
Remarks
This enumeration contains entries for some of the predefined geographic coordinate systems. Please see esriSRGeoCS2Type and esriSRGeoCS3Type for other predefined geographic coordinate systems. A value corresponds to the factory code used in the Projection Engine library.