Geoportale Nazionale: the national GIS portal for Italy provides a host of helpful resources, including orthophotos from multiple years, DEMs at various resolutions, the IGM 25000 series maps, and maps of erosion risk areas, protected areas, etc. Online consultation mainly, but one can create and print maps. Very useful for planning real or classroom-exercise surveys.

Getting Started with GIS and Computer Mapping: Harvard Maps Collection guide to GIS; focused on ArcGIS.

Links to Open Sources GIS Tools: selected by the Harvard Center for Geographic Analysis.

Map Links: Cartographic and Spatial Data on the Internet: the University of Chicago’s selected list of online resources.

Sistema Informativo Territoriale: Wikipedia entry with links to relevant Italian GIS sites.

Città metropolitana di Roma Capitale Geoportale cartografico/Sistema Informativo Geografico: a rich site that provides historical maps of Rome over the centuries (Tempesta, Falda, Nolli, Piranesi, Lanciani and many more) in digital version, as well as current maps (aerial, nautical, vegetation, etc.) documenting the city of Rome and its surroundings.

Cornell University Library’s Guide to GIS Data and Maps: a rich and detailed selection of sites, including online maps, gazetteers, GIS resources, etc.

The Mapping Rome site unites access to:

• Imago Urbis: Giuseppe Vasi’s Grand Tour of Rome, developed by the University of Oregon. A geographic database and website that references the work of two eighteenth-century masters of Roman topography: Giambattista Nolli (1701–1756) [see immediately below], who published the first accurate map of Rome (La Pianta Grande di Roma, 1748); and his contemporary Giuseppe Vasi (1710–1782), who documentated the city and its monuments in various publications, especially Delle Magnificenze di Roma antica e moderna (1747–61)
• The Interactive Nolli Map Website: the 1748 Nolli map of Rome as a dynamic, interactive tool; developed by the University of Oregon
• The Rodolfo Lanciani Digital Archive: the site offers virtual access to a collection of historic depictions amassed by Rodolfo Lanciani (1845–1929), including a vast archive of Lanciani’s notes and manuscripts, as well as works by others including rare prints and original drawings by artists and architects stretching back to the sixteenth century
• Lanciani’s Forma Urbis Romae: a cartographic synthesis of the history of Rome, depicting the city’s diachronic development from ancient to postclassical phases. (The project is in development.)

Old Maps Online: a collaboration between the Great Britain Historical GIS Project based at the University of Portsmouth, UK and Klokan Technologies GmbH, Switzerland that provides for searching historical maps across numerous different collections via a geographical search.

Omnes Viae: places on the road network of the Tabula Peutingeriana, including a re-creation of the missing western part.

Peutinger map: seamless whole, in color, with overlaid layers: a project by Richard Talbert at the University of North Carolina, Chapel Hill. The Peutinger Map is the only map of the Roman world to come down to us from antiquity. Featuring land routes across Europe, North Africa, and the Near East, it was rediscovered around 1500. After coming into the ownership of Konrad Peutinger, for whom it is named, it is today housed at the Austrian National Library in Vienna.

Le piante maggiori di Roma dei sec. XVI e XVII: riprodotte in fototipia. Rome: Biblioteca Apostolica Vaticana, Danesi: 19XX-1931.  
Reproductions of the main maps of Rome from the 16th and 17th Centuries.  Print volumes of this publication are held at the AAR Library. 

Reed College Digital Maps Collection: flood maps of ancient Rome scanned from Gregory S. Aldrete, Floods of the Tiber in Ancient Rome (Baltimore: Johns Hopkins University Press, 2007), maps by the author. Search by "aldrete" and keywords pertaining to your specific interests.

Territori: il portale italiano dei catasti e della cartografia storica: a rich portal uniting cartographic collections from all major Italian state archives. [As of December 2023, the portal is no longer accessible.]

The University of Chicago’s Speculum Romanae Magnificentiae: the Speculum Romanae Magnificentiae is a collection of engravings of Rome and Roman antiquities, the core of which consists of prints published by Antonio Lafreri and gathered under a title page he printed in the mid-1570s.

The University of North Carolina, Chapel Hill’s Ancient World Mapping Center: numerous maps of ancient Rome, Italy, and the Mediterranean; includes the Antiquity À-la-carte application that allows the user to create their own maps, as well as a bibliography and links to other important resources.

The University of Texas’ Perry-Castañeda Library’s Map Collection: includes the Historical Atlas by William Shepher and the maps of Rome.

WorldMap: a platform developed by the Center for Geographic Analysis (CGA) at Harvard. The platform permits to build custom maps, by editing and publishing geospatial information in a collaborative manner. WorldMap is open-source software.

Aquae Urbis Romae: the Waters of the City of Rome: X3D files of 25' contours; GIS data of water related infrastructure with a timeline overlaid on a map of the modern city; includes a project bibliography; Leonardo Bufalini, Roma Map (Rome, 1551).

Archaeological Atlas of Antiquity: a community driven map of places, findspots, buildings, and sites of historical events from antiquity.

Cartographic Site of the Provincia di Roma: contains numerous of helpful links, including maps, data, and more.

CIPRO: Illustrated Catalogue of the Maps of Rome Online: a rich map collection of Rome from 1500 on, by the Bibliotheca Hertziana's Digital Humanities Lab.

Digital Atlas of Roman and Medieval Civilizations: the site provides a rich source of GIS information for Rome, it is mostly from Barrington atlas of the Greek and Roman World.

Digital Atlas of the Roman Empire: a digital atlas from Lund University’s Department of Archaeology and Ancient History; includes GIS in the Pelagios gazetteer interconnection format.

Digital Augustan Rome: the project overlays info from Mapping Augustan Rome (14 AD) on map of modern city; site also makes available a contour map in Acad format.

GeoData@Tufts: developed and maintained by Tufts University Information Technology, in in collaboration with Harvard; provides an open-source, federated web application to rapidly discover, preview, and retrieve geospatial data from multiple repositories. GeoData@Tufts is part of the Open Geoportal.

Geonames: the GeoNames geographical database contains over 10 million geographical names and consists of over 8 million unique features; geonames covers all of Italy and the Mediterranean basin and beyond. The database integrates geographical data such as names of places in various languages, elevation, population and others from various sources and provides lat/long coordinates in WGS84 (World Geodetic System 1984).

Geoportale della Regione Lazio: the GIS portal of the Regione Lazio.

A GIS for the City of Rome: Archives, Architecture, Archeology: articles that appeared in vol. 7, no. 1 (2012) [pp. 28–35] of the journal e-Perimetron, describing the creation of the WebGIS Catasto Gregoriano project; contains numerous references and links to relevant libraries, archives, and museums.

L’Istituto Geografico Militare: a rich source of GIS data for Italy in Shape file format.

The Open Geoportal: a consortium comprised of universities and organizations to help facilitate the discovery and acquisition of geospatial data across many organizations and platforms through a single common search interface. Current partners include: Harvard University, Massachusetts Institute of Technology, MassGIS, Princeton University, Columbia University, Stanford University, the University of California, Berkeley, the University of California, Los Angeles, Yale University, and the University of Connecticut.

Pleiades: this NEH-funded Pleiades is a community-built gazetteer and graph of ancient places providing topographical information about ancient places and spaces, via a search mask recognizing both antique and modern settlement names. The project is part of the STOA Consortium and receives the support of the Ancient World Mapping Center at the University of North Carolina, Chapel Hill, and the Institute for the Study of the Ancient World at New York University.

The Princeton Encyclopedia of Classical Sites: a Project Perseus text-based encyclopedia entry on the history and monuments of Rome.

Roma Sotterranea: underground touring and mapping organization.

Roman Aqueducts: website dedicated to Roman aqueducts, includes drawings and photographs and an article on the Geology of Rome by Evan J. Dembskey. The sister site, ROMAQ: The Atlas Project of Roman Acqueducts, provides additional information.

Stanford Geospatial Network Model of the Roman World (ORBIS): the project aims at reconstructing the time cost and financial expense associated with a wide range of different types of travel in antiquity; includes numerous maps and resources, among which the Stanford Digital Forma Urbis Romae Project, which is dedicated to exploring the Forma Urbis Romae, or Severan Marble Plan of Romemap carved in stone from 203 to 211 AD.

SITAR–Sistema Informativo Territoriale Archeologico di Roma: the SITAR geospatial database is a project of the Soprintendenza Speciale per i Beni Archeologici di Roma that draws on the talents of a joint team of archaeologists, topographers and computer experts. SITAR is a web-based GIS system with altimetric data that requires a username and password (posted on the site).

Struttura della Città: a course site by the Universita degli Studi Roma Tre with links to Rome maps and many other interesting things.

Yorescape: The site expands upon the VSim Repository and Archive and other work by Prof. Frischer at https://www.flyoverzone.com. Yorescape allows you to stream all of Flyover Zone’s virtual tours from web or mobile based devices. The virtual tours include major sites of the ancient world, such as the Roman Forum, the Pantheon, Hadrian's Villa, the Baths of Caracalla and more. The project provides for students, as well as anyone interested in the ancient world, to learn about the history of the sites to visualize what they looked like.

Le Plan de Rome: Restituer la Rome Antique: three-dimensional reconstructions and maps, including a hydrological map linked to year; in French by the Université de Caen, Basse-Normandie.