| I. | Island |
| IA | Infrastructure Analyst (BaySys Technologies Inc.); Iowa |
| IACWD | Interagency Advisory Committee on Water Data |
| IADO | Instituto Argentino de Oceanografia |
| IAEA | International Atomic Energy Agency |
| IAEG | International Assn. of Engineering Geologists |
| IAG | International Assn. of Geodesy |
| IAGS | Inter-American Geodetic Survey |
| IAH | International Association of Hydrogeologists |
| IAHS | International Assn. of Hydrological Sciences = Assn. Internationale des Sciences Hydrologiques |
| IALA | International Assn. of Lighthouse Authorities |
| IALS | Idaho Assn. of Land Surveyors |
| IAOO | International Assn. of Assessing Officers |
| IASI | Infrared Atmospheric Sounding Interferometer |
| IAT | Image Annotation Tape; International Atomic Time |
| IAWPRC | International Assn. for Water Pollution Research and Control |
| IB | Isobar |
| IBC | International Boundary Commission (U.S.-Canada) |
| IBDF | Instituto Brasileiro de Desenvolvimento Florestal |
| IBG | Inst. of British Geographers |
| IBGE | Instituto Brasileiro de Geografia e Estadistica |
| IBIS | Image-Based Information System |
| IBM | International Business Machines (corp.); International boundary marker |
| IBRD | International Bank for Reconstruction and Development (World Bank) |
| IBSP | Idaho Bureau of State Planning |
| IBWC | International Boundary and Water Commission (Mexico-U.S.) |
| IC | Integrated circuit(s) |
| ICA | International Cartographic Assn. = Assn. Cartographique Internationale |
| ICACET | International Cartographic Assn. Committee on Training |
| ICAITI | Instituto Centro Americano de Investigacion y Tecnica Industrial |
| ICAO | International Civil Aviation Organiztion |
| ICA-USNC | International Cartographic Assn. U.S. National Committee |
| ICC | Institut Cartografic de Catalunya; Interstate Commerce Commission (U.S.); International Cartographic Conference |
| ICCP | Inst. for Certification of Computer Professionals |
| ICE | Information Center for the Environment (UCD) |
| ICED | Intraprofessional Council on Environmental Design |
| ICES | Institution of Civil Engineers (UK); Initial Graphics Exchange Specifications |
| ICEX | Ice and Climate Experiment |
| ICGC | Instituto Cubano de Geodesia y Cartografia |
| ICGWM | International Clearinghouse for Ground Water Models |
| ICHC | International Conference on the History of Cartography |
| ICITV | Institut de la Carte International du Tapis Vegetale |
| ICM | Instituto Cartografico Militar |
| ICMP | Internet Control Message Protocol |
| ICMSSR | Interagency Committee on Meteorological Services and Supporting Research |
| ICONA | Instituto Nacional para la Conservacion de la Naturaleza (Spain) |
| ICR | Intelligent Character Reader |
| ICT | Information and communication technologies |
| ICW | International Computer Works, Inc. |
| ID | Identification; Interface device; Idaho |
| IDAS | Image Data Analysis Systems |
| IDC | International Data Corp. |
| IDCCC | Interior Digital Cartographic Coordination Committee (U.S.) |
| IDD | Information and data dissemination |
| IDE | Imbedded Drive Electronics |
| IDEN | Identification module |
| IDFG | Idaho Dept. of Fish and Game |
| IDIMS | Interactive Digital Image Manipulation System |
| IDIQ | Indefinite delivery/indefinite quantity |
| IDL | Idaho Dept. of Lands; Interactive Data Language; Interface Definition Language |
| IDLH | Immediately dangerous to life and health |
| IDR | Interface drawing |
| IDS | Information Decision Systems (firm) |
| IDWO | Intelligence Div., War Office (U.K.) |
| IDWR | Idaho Dept. of Water Resources |
| IEMVT | Institut d'Elevage et de Medecine Veterinaire des Pays Tropicaux |
| IEP | Independent electric plant |
| IERS | International Earth Rotation Service |
| IES | Inst. for Environmental Sciences |
| IF | Frame identification |
| IfAG | Institut fur Angewandte Geodasie |
| IFF | Interchange Format File (Commodore Amiga) |
| IFLA | International Assn. of Library Asociations and Institutions |
| IFN | Service de l'Inventaire Forestier National (France) |
| IFOV | Instantaneous Field of View |
| IFP | Institut Francais de Pondicherry; Institut Francais du Petrole |
| IFR | Instrument Flight Regulation |
| IFREMER | Institut francais de recherche pour l'exploitation de la mer |
| iFS | Internet File System (Oracle Corp.) |
| IFSAR | Inter-ferometric Synthetic Aperture Radar |
| IFSARE | Inter-ferometric Synthetic Aperture Radar for Elevation |
| IG | Instytut Geologiczny (Poland) |
| IGA | Istituto Geografico de Agostini |
| IGAC | Instituto Geografico "Agustin Codazzi" |
| IGBF | Institut Geographique de Burkina Faso |
| IGBP | International Geosphere-Biosphere Programme |
| IGC | International Geologic Congress; Intelligent Graphics Controller; Informative Graphics Corp. |
| IGCI | Institut Geographique de la Cote d'Ivoire |
| IGCP | International Geological Correlation Program; Instituto Geografico e Cadastral (Portugal) |
| IGDC | Interagency Geographic Data Committee (U.S.) |
| IGDS | Interactive Graphics Design System (software); Intergraph Design Software |
| IGEBU | Institut Geographique de Burundi |
| IGES | Initial Graphics Exchange Specification; International Graphics Exchange System |
| IGF | Inset Graphics Format |
| IGFCOT | Institutul de Geodezie, Fotogrammetrie, Cartografie si Organizarea Teritoriului (Romania) |
| IGG | Institutul de Geologie si Geofizica (Romania) |
| IGGSP | Instituto Geografico e Geologico de S~ao Paulo |
| IGIF | International Geographic Information Foundation |
| IGIS | Integrated Geographic Information System; Intelligent GIS |
| IGL | Interactive Graphics Library |
| IGLD 85 | International Great Lakes Datum of 1985 |
| IGM | Instituto Geografico Militar |
| IGME | Inst. of Geology and Mineral Exploration (Greece); Instituto Geologico y Minero de Espa~na |
| IGMI | Istituto Geografico Militare Italiano |
| IGN | Institut geographique national; Instituto Geografico Nacional |
| IGNB | Institut Geographique National (Belgium) |
| IGNC | Institut Geographique National Congolaise |
| IGNTG | Instituto Geografico Nacional "Tommy Guardia" (Panama) |
| IGS | Information & Graphics Systems Inc.; International GPS Service; Idaho Geological Survey; Indiana Geological Survey; Geological Survey of Israel |
| IGSN71 | International Gravity Standardization Net 1971 |
| IGT | Integrated GPS Technologies Inc. |
| IGU | International Geographical Union; Instituto Geografico Universitario (Dominican Republic) |
| IGUG | Intergraph Graph Users Group |
| IGWMC | International Ground Water Modeling Center |
| IGY | International Geophysical Year |
| IGZa | Institut Geographique du Zaire |
| IHA | Instituto Hidrografico de la Armada (Chile) |
| IHAC | Instituto Hidrografico de la Armada, Chile |
| IHB | International Hydrographic Bureau |
| IHD | International Hydrological Decade |
| IHGC | International Health Geographics Conference |
| IHO | International Hydrographic Organization |
| IHP | International Hydrologic Program |
| IHSI | Institut Haitien de Statistique de d'Informatique |
| IIAF | Idaho Image Analysis Facility |
| IICT | Instituto de Investigac~ao Cientifica Tropical (Portugal) |
| IIGS | Initial Image Generating System |
| IIPL | Interactive Image Processing Laboratory |
| IIS | Internet Information Server |
| IJC | International Joint Commission (U.S. & Canada) |
| IKU | Institutt for Kontinentalsokkelundersokelse (Norway) |
| IL | Illinois |
| ILC | Interim Library Catalog |
| ILEX | Interactive Landsat Executive (NASA software) |
| ILH | Internationales Landkartenhaus (Stuttgart) |
| ILI | Inst. for Land Information |
| ILIM | Inst. for Land Information Management (University of Toronto) |
| Ill. | Illinois |
| ILLIAC | Illinois Institute for Advanced Computation |
| ILS | Intelligent Library System (Lockheed Martin) |
| ILWIS | Integrated Land and Water Information System (ITC) |
| IM | Information management |
| IMA | Intermap Analytic |
| IMACUAC | Information Management and Computer Utilization Advisory Committee |
| IMAG | Information Management Advisory Group |
| IMACS | Integrity Monitoring and Control Software (Javad Positioning Systems) |
| IMAGE | Integrated Mapping and Geographic Encoding System |
| IMAGE 100 | Interactive Multispectral Image Analysis System (GE) |
| IMAN | Image Analysis (system); Intermap Analytic Nucleus |
| IMAP | Input, Management, Analysis, and Presentation |
| IMC | Image Motion Compensator |
| IMCoS | International Map Collectors Society |
| IMDA | International Map Dealers Assn. |
| .IMG | ADRG image format (USDMA) |
| IMGW | Instytut Meteorologii i Gospodarki Wodnej (Poland) |
| IMLS | Institute of Museum and Library Services (US) |
| IMO | International Maritime Organization |
| IMP | Integrated Micro Products Inc. |
| IMPAC | Image Analysis Computer Package (Egbert Scientific) |
| IMS | Intermediate map scale; Image Manipulation System; Internet Map Server (ESRI) |
| IMSI | International Microcomputer Software, Inc. |
| IMT | Information Management Technologies (Firm); Internet Media Type |
| IMTA | International Map Trade Assn. |
| IMW | International Map of the World |
| in. | Inch; inches |
| IN | Indiana |
| INC | Institut National de Cartographie |
| INCG | Institut National de Cartographie du Gabon; Institut Geographique National Guineen |
| Ind. | Indiana |
| INDEC | Instituto Nacional de Estadistica y Censos (Argentina) |
| INE | Instituto Nacional de Estadistica (Ecuador, Guatemala) |
| INEAC | Institut National pour l'Etude Agronomique du Congo |
| INEGI | Instituto Nacional de Estadisticas, Geografia e Informatica (Mexico) |
| INETER | Instituto Nicaraguense de Estudios Territoriales |
| INFORM | Information Network for Operational Resources Management (Arizona) |
| INGEMMET | Instituto Geologico Minero y Metalurgico (Peru) |
| INGEO- MINAS |
Instituto Nacional de Investigaciones Geologico-Mineras (Colombia) |
| INGM | Instituto Nacional de Geologia |
| INLT | Inlet |
| INMARSAT | International Maritime Satellite (organization) |
| INMG | Instituto Nacional de Meteorologia e Geofisica (Portugal) |
| INMH | Instituto Nacional de Meteorologia y Hidrologia (Ecuador) |
| INPE | Instituto das Pesquisas Espaciais (Brazil) |
| INQUA | International Union for Quaternary Research |
| INRA | Institut National de Recherche Agronomique (France) |
| INRAT | Institut National de la Recherche Agronomique de Tunisie |
| INS | Inertial Navigation System |
| INSEE | Institut National de la Statistique et des Etudes Economiques (France) |
| INSMAP | International Symposium on Marine Positioning |
| Inst. | Institute |
| INSTAAR | Inst. of Arctic and Alpine Research (Univ. of Colorado) |
| INTA | Instituto Nacional de Tecnologia Agropecuaria (Argentina) |
| INTELSAT | International Telecommunications Satellite (organization) |
| INTRISCA | Integrated Resource Inventory for South-Central Alaska |
| INUPAL | Informaciones Unidas para America Latina (Chile) |
| IO | Input/output; Interior orientation |
| I/O | Input/output |
| IOC | Intergovernmental Oceanographic Commission; Initial operational capability |
| ION | Inst. of Navigation |
| IOP | International Organisation of Palaeobotany |
| IOS | Institute of Oceanographic Science (Great Britain) |
| IP | Internet protocol; Image point |
| IPA | Imagery Product Archive (USDMA) |
| IPAM | Instituto de Pesquisa Ambiental da Amazonia |
| IPCS | Image Production Control System |
| IPE | Image processing engine |
| IPF | Image Processing Facility (GSFC) |
| IPGP | Institut de Physique du Globe de Paris |
| IPRG | Inst. for Petroleum Resources and Geophysics (Israel) |
| IPLSA | Illinois Professional Land Surveyors Assn. |
| IPOSTEL | Instituto Postal Telegrafico (Venezuela) |
| IPP | Integrated Plotting Package |
| IPS | Image processing system; Inertial Positioning System |
| IPT | Informatica per il Territorio; Instituto de Pesquisas Tecnologicas (Sao Paulo, Brazil); Integrated Product Team |
| IPX | Internet Packet Exchange |
| IR | Imaging Radiometer; Infrared |
| IRAT | Institut de Recherches en Agronomie Tropicale (France) |
| IRC | Intergraph Registered Consultant |
| IR. CH. | Iron chimney |
| IR. CH.S.A. | Iron chimney with spark arrestor |
| IRD | Information Resources Division (Arizona) |
| IRDB | Integrated regional database |
| IRDS | Information Resource Dictionary System |
| IRF | Internal Raster File; Internal Raster Format |
| IRG | Inter-Record Gap |
| IRICC | Interagency Resource Information Coordination Council |
| IRIS | Infrared Interferometer/Spectrometer; Interim Research and Intelligence Service (U.S. Dept. of State) |
| IRIS R&A | Research and Analysis Branch, Interim Research and Intelligence Service (U.S. Dept. of State) |
| IRLSA | Illinois Registered Land Surveyors Assn. |
| IRRI | International Rice Research Inst. |
| IRS | Internal Revenue Service (U.S.); Information retrieval system; Indian Remote Sensing (Satellite) |
| IRSA | Inst. of Remote Sensing Applications |
| IRWA | International Right of Way Assn. |
| IRWD | Irvine Ranch Water District |
| Is. | Island |
| IS | International Standard |
| I.S. | John Speed |
| ISA | Institute of Surveyors of Australia; Internet Starter Applications |
| ISABU | Institut des Sciences Agronomiques au Burundi |
| ISAMS | Improved Stratospheric and Mesospheric Sounder |
| ISAPI | Internet Server Application Programming Interface |
| ISBD(CM) | International Standard Bibliographic Description for Cartographic Materials |
| ISBD(ER) | International Standard Bibliographic Description for Electronic Resources |
| ISC | Information Systems Council |
| ISCEM | International Society of Curators of Early Maps |
| ISD | Information Services Div. |
| ISDN | Integrated Services Digital Network |
| ISEA | Icosahedral Snyder equal area (projection) |
| ISERT | Institut Superieur pour les Etudes et Recherches Scientifique et Techniques (Djibouti) |
| ISGS | Illinois State Geological Survey |
| ISI | Image Subsystem Interface; Information Systems Inventory (EPA); Interpretation System, Inc. |
| I-SITE | Intelligent Screening of Imagery for Teleophthalmology |
| Isl. | Island |
| ISL | Island |
| ISLP | Land-tied island |
| ISLS | Islands |
| ISM | Interpretive Structural Modeling |
| ISMS | International Society for Mine Surveying |
| ISO | Imaging Spectrometer Observatory; International Standards Organization |
| ISP | Internet service provider |
| ISPI | Intermediate-scale Product Inventory |
| ISPLS | Indiana Society of Professional Land Surveyors |
| ISPRS | International Society for Photogrammetry and Remote Sensing |
| ISR | Information Storage and Retrieval |
| IS&T | Information Systems and Technology |
| ISTAT | Istituto Centrale di Statistica (Italy) |
| ISTD | Inter-Services Topographical Dept. (Great Britain) |
| ISTH | Isthmus |
| ISU | International System of Units |
| ISURL | Indiana State Univ. Remote Sensing Laboratory |
| IT | Information technology; Integration Technologies Inc. |
| I.T. | Idaho Territory |
| ITAA | Information Technology Assn. of America |
| ITC | International Inst. for Aerospace Survey and Earth Sciences (Netherlands; formerly International Training Centre for Aerial Survey); International Trade Commission |
| ITCA | International Topographic Composition Assn. |
| ITD | Interim Terrain Data |
| ITE | Institute of Terrestrial Ecology (Great Britain) |
| ITF | INTERLIS Transfer Format |
| ITFE | Inductive terrain feature extraction |
| ITRF | International Terrestrial Reference Frame |
| ITRM | Information Technology Resouces Management (standard, Virginia) |
| ITRS | International Terrestrial Reference System |
| ITS | Intelligent transportation system |
| ITSA | Independent Travel Stores Assn. |
| ITU | Image Transfer Unit; International Telecommunications Union |
| IUE | International Ultraviolet Explorer |
| IUGG | International Union of Geodesy and Geophysics |
| IUGS | International Union of Geological Sciences |
| IUSM | International Union for Surveying and Mapping |
| IVHS | Intelligent Vehicle Highway Systems |
| IW | Information Warfare |
| IWARDS | Iowa Water Resources Data System |
| IWIS | International Water Information System |
| IWPC | Inst. of Water Pollution Control |
| IWRA | International Water Resources Assn. |
| I2S | International Imaging Systems Inc. |