Digital geologic mapping is the process by which geological features are observed, analyzed, and recorded in the field and displayed in real-time on a computer or personal digital assistant (PDA). The primary function of this emerging technology is to produce spatially referenced geologic maps that can be utilized and updated while conducting field work.
Traditional geologic mapping
Geologic mapping is an interpretive process involving multiple types of information, from analytical data to personal observation, all synthesized and recorded by the geologist. Geologic observations have traditionally been recorded on paper, whether on standardized note cards, in a notebook, or on a map.
Mapping in the digital era
In the 21st century, computer technology and software are becoming portable and powerful enough to take on some of the more mundane tasks a geologist must perform in the field, such as precisely locating oneself with a GPS unit, displaying multiple images (maps, satellite images, aerial photography, etc.), plotting strike and dip symbols, and color-coding different physical characteristics of a lithology or contact type (e.g., unconformity) between rock strata. Additionally, computers can now perform some tasks that were difficult to accomplish in the field, for example, handwriting or voice recognition and annotating photographs on the spot.
Digital mapping has positive and negative effects on the mapping process; only an assessment of its impact on a geological mapping project as a whole shows whether it provides a net benefit. With the use of computers in the field, the recording of observations and basic data management changes dramatically. The use of digital mapping also affects when data analysis occurs in the mapping process, but does not greatly affect the process itself.
Advantages
Data entered by a geologist may have fewer errors than data transcribed by a data entry clerk. Data entry by geologists in the field may take less total time than subsequent data entry in the office, potentially reducing the overall time needed to complete a project. The spatial extent of real world objects and their attributes can be entered directly into a database with geographic information system (GIS) capability. Features can be automatically color-coded and symbolized based on set criteria. Multiple maps and imagery (geophysical maps, satellite images, orthophotos, etc.) can easily be carried and displayed on-screen. Geologists may upload each other's data files for the next day's field work as reference. Data analysis may start immediately after returning from the field, since the database has already been populated. Data can be constrained by dictionaries and dropdown menus to ensure that data are recorded systematically and that mandatory data are not forgotten Labour-saving tools and functionality can be provided in the field e.g. structure contours on the fly, and 3D visualisation Systems can be wirelessly connected to other digital field equipment (such as digital cameras and sensor webs)
Disadvantages
Computers and related items (extra batteries, stylus, cameras, etc.) must be carried in the field. Field data entry into the computer may take longer than physically writing on paper, possibly resulting in longer field programs. Data entered by multiple geologists may contain more inconsistencies than data entered by one person, making the database more difficult to query. Written descriptions convey to the reader detailed information through imagery that may not be communicated by the same data in parsed format. Geologists may be inclined to shorten text descriptions because they are difficult to enter (either by handwriting or voice recognition), resulting in loss of data. There are no original, hardcopy field maps or notes to archive. Paper is a more stable medium than digital format.
Educational and scientific uses
Some universities and secondary educators are integrating digital geologic mapping into class work. For example, The GeoPad project describes the combination of technology, teaching field geology, and geologic mapping in programs such as Bowling Green State University’s geology field camp. At Urbino University (Italy) :it:Università di Urbino, Field Digital Mapping Techniques are integrated in Earth and Environmental Sciences courses since 2006 . The MapTeach program is designed to provide hands-on digital mapping for middle and high school students. The SPLINT project in the UK is using the BGS field mapping system as part of their teaching curriculum