DOQQ

DOQQ stands for Digital orthophoto quarter quadrangle. The image above is a digital orthophoto of Sabine Pass, Texas enlarged to show a one meter resolution.

DEM - Digital elevation model

A digital elevation model (DEM) is a digital file consisting of terrain elevations for ground positions at regularly spaced horizontal intervals. This is an image of global elevation.

DLG - Digital line graph

Digital line graphs are digital vector representations of cartographic information derived from USGS maps and related sources. Depending on the scale, layers such as PLSS, boundaries, transportation, hydrography, hypsography, non-vegetative features, survey control and markers, manmade features and vegetative surface cover may be available. The image above is of a 7.5 minute DLG showing boundary, hydrography and transportation layers in Dancyville, TN.

DRG - Digital raster graphic

A digital raster graphic (DRG) is a scanned image of a U.S. Geological Survey (USGS) standard series topographic map, including all map collar information. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Universal Transverse Mercator projection. The horizontal positional accuracy and datum of the DRG matches the accuracy and datum of the source map. The map is scanned at a minimum resolution of 250 dots per inch. This information was taken from http://topomaps.usgs.gov/drg/.

Isopleths

Isopleths are contour lines that connect points of equal value. Used by meterologists some typical isopleths include isotherms, isobars and isotachs among others. This image shows rainfall isopleths in the Ten Mile River water shed in California during the years 1961-1990.

Isopach

Isopachs are contours that display the stratigraphic thickness of a rock unit as opposed to the true vertical thickness. This is an image from the Kansas Geological Survey of the Riverton coal. It shows that Riverton coal stays at a fairly consistent thickness over an average distance of 5 miles.

Isohyets are lines joining equal precipitation on a map. This map shows the mean annual rainfall in Tasmania in the year 2006.

Isotachs are lines on a given surface connecting points with equal wind speed. This image is from a 12 Hour Forecast of 250-850 mb Qn vectors,thickness and isotachs on May 12, 1997.

Isobars

Isobars are constant lines of equal pressure generated from mean sea level pressure reports. This image is from a diagnosis of a distinct warm front band over Finland in June 1998.

LIDAR

LIDAR is a remote sensing system used to collect topographic data. This is a LIDAR image of Ground Zero taken September 27, 2001.

Doppler radar

Doppler radar uses the doppler effect to measure relative velocity information from a radar system. This is a Doppler radar of Hurricane Katrina.

Black and white aerial photo

This black and white aerial photo was used to determine whether or not dredged material from Pearl and Honolulu Harbors had any geological and environmental impacts on Mamala Bay. The photo showed that the dredged material dumped into Mamala Bay left a distinct acoustic signature.

Infrared aerial photo

Aerial infrared photos give scientists a tool to study landforms, health of vegetation, environmental pollution, and other effects that human activities have on the Earth's surface. This photo is of an upland study forest in Fort Leavenworth, Kansas in May 2000. Active vegetation is shown as reds and pinks.

Cartographic animations

Cartographic animation is a visualization technique that is used to represent geographic phenomena through interrelations with the data's components, location and time. This map represents deaths in Colorado due to certain diseases. If you were to roll your cursor over each box on the right-hand side, it would show on the map the percentages of death due to that certain disease.

Statistical map

A statisical map displays a certain variable distributed across a geographical region. This map shows the ratio of unmarried men to unmarried women in the U.S. in the year 2000.

Cartogram

This example of a cartogram was found at issrweb.asu.edu/services/gis/sample-maps.html