Fieldlog is a software tool developed by the Geological Survey of Canada (GSC) to aid geologists in the digital management of geologic field data. It provides a means to digitally record, retrieve, display and analyze field observations, and to supplement cartographic map preparation and geologic interpretation. Fieldlog maintains a relational database within an AutoCAD environment and provides connection to several popular GIS systems through export formats. It is founded on a data model which consists of geological concepts common to the mapping process. Project databases, their cartographic representation, referenced coordinate systems and glossaries of geologic terms are completely configured and modifiable by the geologist. The data model defines much of the internal database and cartographic behavior, insulating the geologist from many technical details and providing enhancements to traditional database and cartographic operations. Sophisticated data entry and database query, including specialized geologic diagrams, are present to augment the map-making process. Integration with mobile computing devices, as well as with more standard methods of field note-taking such as traditional field notebooks, permits a broad range of data recording options. Fieldlog has been an integral component of the GSC's regional mapping and rapid digital map publication methodology since 1991.
Geologic maps depict geologic observations and interpreted geologic objects which are often inferred from the observational data. The exact representation of these objects as map entities is scale dependent and the geometry may vary between point, line, polygon, surface and volumetric objects. The identification or deduction of geologic objects is iterative: evidence is gathered and hypotheses are formulated which are supported or refuted by further evidence. This is an analytic process where data are mutable and prone to re-classification or re-interpretation over the course of the mapping (fig. 1). In this context a field system must ultimately be an aid to the thinking process as much as it must be an efficient mechanism to record and store thoughts. Effective gathering of data is the first priority in this process, soon followed by a need to dissemble and recast the data into different scenarios.
Figure 1. A cartoon of the field mapping process. [60 K GIF]
Under Fieldlog a geologic map usually begins as one or more digital topographic base maps which are originally purchased from some third party, typically a government agency. The maps may also be directly scanned and digitized. Once acquired, the base maps are registered in some coordinate system which defines their geographic position. A project database is constructed by the field geologist to contain the field data and to interact with the maps. Project databases may be derived from corporate templates or may be begun anew. Once a project database is established data can be simultaneously added to the maps and to tables in the database. In this process field data may be displayed on several maps and a map may contain data from several projects. Though Fieldlog will allow several projects to be active during a session, its functions will only operate on one project at a time. For instance, query contents cannot be selected from more than one project in any one query.
Field observations typically are sites or boundaries, and these are added to the base map as points or line segments. Their attributes are entered into the database at the same time. These supporting data are manually entered into the Fieldlog database from field notebooks or forms, or are digitized from air photographs and topographic maps using small digitizing tablets. They may also be imported from mobile computing devices such as GPS (satellite-based Global Positioning Systems) and PDA (hand-held Personal Digital Assistants) or more sophisticated portable units. Some of the data are symbolized on the map--either via manual digitization or through importation and plotting via queries--and some of them reside in the database as supporting evidence. This data entry stage typically involves the entry of site information into the database and the display of select portions on the map. Boundary data may also be recorded and digitized at this time. Mesoscopic observations such as station locations, structural measurements and rock type characteristics are recorded and plotted with Fieldlog, and macroscopic observations such as contacts, folds and faults are drawn using AutoCAD's line and polygon drawing mechanisms--they may also be imported from preexisting digital geology maps or from portable field computers. Once in digital form, the evolving map is plotted at scale on a regular (i.e. daily) basis using page size printers. The plotted pages are joined, often with tape, and this growing paper mosaic represents the field map. Often interpretive features, such as geological contacts, are sketched by hand onto this mosaic, and subsequently digitized when and if confirmed. As the geological story unfolds, the various hypotheses--depicted as disconnected boundaries on the map--are joined to form polygons which eventually partition the geographic extent of the map. In this process observed supporting data are often reclassified using Fieldlog's editing capabilities which ensure that map and database equivalency is maintained. AutoCAD's standard functions are used to edit all non-Fieldlog data.
The evolution of geologic insight for a map area often involves the utilization of a myriad of tools such as stereographic plots as well as geophysical overlays. Fieldlog provides either the resources to perform these tasks or to export the data painlessly so that it can be further integrated into more sophisticated and specialized systems such as GIS or other geological plotting packages. Ultimately the results of such deliberation are returned to Fieldlog as new geologic objects on the map, or as changes to existing map entities. The end result is a geologic field map with an underlying database of field observations.
Fieldlog maintains field observations in a relational database which is linked to one or more digital AutoCAD maps. In a typical project most field data are stored in the relational database, and a subset of these data are displayed on the map. However, some map entities, such as geological boundaries, may exist solely as cartographic objects without being additionally described in the field database. Fieldlog permits map entities of any geometric shape (e.g. points, lines or polygons) and cartographic type (e.g. symbols, text, lines, etc.) to be described in the database. Furthermore, the data entry process allows point entities to be simultaneously added to the database and map as symbols or text. This procedure does not hold for other map entities such as lines or polygons: they must first be added to the map using AutoCAD's standard cartographic functions, and then linked to a database description during data entry. Each AutoCAD map, and thus each map entity, has positional information referenced to a previously established coordinate system taken from Fieldlog's catalog of cartographic projections. Positional information is copied from the map to the Fieldlog database only for designated points, whereas positional information for other map entities remains in the AutoCAD map.
When entering data, field observations may be typed, locations may be digitized, and either can be imported from external text or database tables. A digital topographic map is usually used as a backdrop onto which the observations are plotted. When observations are imported from external sources such as mobile data collection devices, they are retrieved from the database and plotted to the map via a user directed query process. When observations reside in paper notebooks or forms, they are manually entered by selecting a table and entering information into the columns of a new row. Column contents are verified according to various parameters configured by the geologist. If verified, the new row is inserted into the table and the values of selected columns are optionally positioned on the digital map through visual location, or via digitization from some source such as a topographic map or air photograph. When several observations occur at a site, the data may be stored in more than one table or in more than one row in a table. In this case Fieldlog will then propagate critical values between rows, or from one table to another in order to reduce data entry time and to enforce proper data connectivity between database tables (i.e. referential integrity constraints). For example site identifiers will propagate to all rows and tables until a new site is specified. Fieldlog also permits customizable dictionaries of geological terms to be created and attached to columns for data entry purposes (fig. 2) and for the maintenance of semantic consistency of terminology. Once a dictionary is attached to a column, the contents of the column are restricted to one or, optionally, more terms from the dictionary. Dictionaries are unlimited in the number of terms they may contain.
Figure 2. Data entry using a hierarchical profile. [57 K GIF]
Fieldlog v3.0 takes advantage of affordable pen-based data entry technology offered by the Apple Newton, by exporting a field database structure to the Newton and importing collected data from it. The Fieldlog database format is transferred to the Apple Newton where it is displayed intact, including all relevant hierarchical profiles (fig. 3). Commercial software (Fieldworker) operates on the Newton to receive the Fieldlog project template and present it for data entry. Data may be hand-written on a touch-sensitive screen, or typed on a small, screen resident keypad. A GPS can be connected to the Newton and its locations directly read by the Fieldworker software, permitting complete data entry to occur in the field. The resultant data are exported to Fieldlog in a specialized text file format, and are merged into the project database. Fieldlog can also interface to mobile computing devices other than the Apple Newton using standard import/export formats.
Figure 3. A Fieldlog project database on the Apple Newton, using the Fieldworker software for data entry. [60 K GIF]
Underlying all Fieldlog components and functions is a data model which consists of geologic concepts and their rules of interaction (i.e. an articulation of intuitive geological heuristics). The data model is an abstraction of the geological mapping process where concepts common to most geologic mapping activities are identified and their general relationships defined. In this sense the mapping process is grossly distilled to a series of commonly performed activities and commonly observed geologic objects. Fieldlog provides this basic conceptual structure to the geologist and permits it to be implemented by individuals in very different ways by refining and adapting the concepts into a personalized database definition. In this process the data model's geologic concepts are translated into relational database constructs for data processing, and the geologist is insulated from many of the routine database operations.
The Fieldlog data model necessarily deals with spatial as well as geologic concepts. Observed data originates from a geographic location which may be a region (outcrop) or a site (field station). Often these observations are made along a traveled path which defines a geographic route (traverse). In the course of a survey, sites and regions are encountered on one or more routes, and sites may occur within regions. Some observations are further defined by a spatial partition, often vertical, within their site or region of origin such as a stratigraphic section at some field site or drill core segments within a drill hole. Once spatial positioning is accounted for, the relationships between observed data are semantic in nature as observers are discipline specific. Geologists observe rock, soil scientists observe soil, biologists observe flora or fauna, etc. These themes are generally described in terms of their composition or disposition, all of which may be sampled. Composition describes a theme's internal constitution, such as mineralogy or alteration within rocks, whereas disposition describes the theme in terms of its setting and the processes leading to its specific, often physical, configuration. Disposition may be described within a specific theme type or it may be macroscopic to the theme. For instance, structural processes display the following characteristic: it is possible to discuss faulting within a rock type at a site, and also to discuss regional scale faulting which encompasses the site. All of themes (rocks), compositions (minerals) or dispositions (structures) may be sampled. Samples may further undergo various analyses such as geochemical, geochronological, petrographic, etc. Themes, compositions, dispositions, samples and analyses can be attributed to any spatial location, whether it is a site or partition within a site. Therefore, other than their vertical partitions, stratigraphic sections and drill hole segments can be described in the same general manner as non-partitioned sites or regions. This implies that field survey, drill hole and stratigraphic section data can coexist within one semantic model, and also within a single database structure. Fieldlog has indeed often been applied in these various situations. Finally, Fieldlog also recognizes geologic boundaries, units, legends, and references as valid data types. The data model is summarized below (fig. 4):
Figure 4. Fieldlog's General Field Data Model. Reference and Dictionary concepts have been omitted for presentation purposes. References and Dictionaries may be related to any of the general concepts portrayed in this diagram The influenced-by relation between units, boundaries and traverses, outcrops has also been omitted for presentation purposes. [66 K GIF]
Fieldlog operates in AutoCAD's cartographic environment which it extends to include additional geographic and geologic processing capability. AutoCAD was initially chosen because of its wide usage, its cartographic excellence, its liberal development environment and its ability to operate on many hardware and operating system platforms. Of the many operating systems supported by AutoCAD, Fieldlog will currently function within DOS, Windows 3.1, 95 and NT. It also currently utilizes AutoCAD release 12, but it is expected to operate within AutoCAD release 13 by the 1997 summer field season.
Fieldlog is able to interact with a variety of database systems, primarily because all relational database activity is performed transparent to the geologist using SQL (Structured Query Language), which is platform independent. Relational databases such as dBase, ODBC (e.g. MS-Access), Oracle, etc., are thus accessible from this modern client-server environment.
Queries are performed using a visual interface which permits the user to thematically filter the database and view the results in tabular form. Database filters are constructed using conditional statements which are composed of thematic, spatial or hierarchical components and which are connected with "AND" or "OR" logical operators (fig. 5a). Query results are displayed as a virtual table (fig. 5b). Row contents in the resulting table may be browsed, deleted and modified singly or globally. The results may also be plotted to the active AutoCAD map using customized geological map symbols (fig. 5c), they may be manipulated to produce custom diagrams (i.e. stereonet, rose, geochemical, and pie diagrams) and may be exported to a variety of formats. Supported query export formats include tabular representations as text files and database tables, as well as direct translations to GIS using the following exchange mechanisms: Arc/Info-ArcView E00, MapInfo MIF, and SPANS TBA formats. The user can designate which columns to export and can scale the symbology or alter the coordinate system for each type of format.
Figure 5A. Query menu. [Total of 160 K for 3 GIFs]
Figure 5B. Query results and plot options.
Figure 5C. Query results plotted as symbols, rose and stereo diagrams -- overlain on geological contacts.
Fieldlog permits ellipsoids, projections and transformations to be created and modified. In this way it is possible to create a personalized catalog of coordinate systems. Projections are restricted to variations of the following basic kinds: geographic, transverse mercator, universal transverse mercator, lambert conformal conic, double stereographic, and user defined coordinate systems. Coordinates and map entities may be converted from one projection to another. Transformations may further be defined to convert coordinates from a user grid to other grids or orthogonal projections.
At present, fieldlog is distributed electronically, on an "as is" basis, at no cost from the following Internet address: http://gis.nrcan.gc.ca. The Internet site presents a registra-tion form which must be completed prior to downloading the software. A bound version of the users guide and tutorial will also be available for purchase as a GSC open file from the GSC Publications office after the 1997 summer field season. This manual is available, and will remain available in the future, in electronic formats on the Internet site. Formal software support is not provided by the GSC, but the author will respond to questions and comments regarding the software. Short courses on its use are occasionally presented at scientific meetings and at the GSC.
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