B.E. Elliott, P.G. Killeen, K.A. Pflug
and C.J. Mwenifumbo,
Geological Survey of Canada, 601 Booth St., Ottawa, K1A0E8,
LogView: Borehole Geophysical Software for Presentation Quality Output; in Proceedings of the 6th International MGLS Symposium on Borehole Geophysics for Minerals, Geotechnical and Groundwater Applications; Santa Fe, October 22-25, 1995.
The Borehole Geophysics Section of the Geological Survey of Canada (GSC) has developed LogView, a Microsoft Windows 3.1 application, to provide presentation quality screen and hardcopy output in both colour and black and white to display combinations of logs generated from a series of GSC logging probes. LogView has been released as GSC Open File 3055, and is available through the GSC bookstore.
LogView can be used to view, print and zoom/pan borehole logs and associated lithology. The data file formats and software allow logging parameters recorded with different depth intervals to be plotted beside one another. Logs of data can be stretched, compressed, depth shifted and smoothed for display and a limited amount of annotation can be added to enhance the presentation.
LogView creates 'log display list' files, that allow attributes for a specific layout of logs to be saved for future use and revision.
Windows on&endash;line help is provided, both from a HELP menu and from individual screens.
Details about the menus, file formats and features of LogView are presented, including examples of plots utilizing different features.
The Borehole Geophysics Section, Mineral Resources Division, of the Geological Survey of Canada (GSC), carries out research projects directed at advancing the use of borehole geophysical methods as applied to mineral exploration, geotechnical and environmental problems.
Applying ideas resulting from many years use of earlier GSC in-house software plotting packages and using Microsoft Windows 3.1, LogView was developed to facilitate the layout, viewing and printing of combinations of logs generated from a series of GSC logging probes used in this research.
Borehole geophysical logs, associated geology, and other related data such as assays can be viewed on screen (with zoom/pan mode available) and printed on any Windows 3.1 supported printer.
Logging parameters recorded with different probes and different sampling rates do not have to be interpolated to the same depth intervals. This allows the maximum detail in each data set to be retained.
Displayed logs of data can be stretched, compressed, depth shifted and smoothed. Attributes ranging from lithology log area fills, colours, line styles, titles and font sizes can be edited and annotation objects can be added to enhance the presentation. While manipulating screen displays, the cursor position can be displayed in terms of log units (depth and parameter) or as X-Y paper position in mm.
A lithology legend, with identifying labels for the lithology colours and patterns, can be placed anywhere on the layout. A depth axis reference grid at regular depth intervals or at specific depths can also be added to the display.
In the design of a single layout, LogView allows for three different colour tables to be used. This would, for example, let you design a layout in colour in one colour table, and in black and white in a second colour table, without having to specify size and other attributes twice.
The attributes for a specific layout can be saved for future use and revision.
The on-line help can be accessed from either the HELP MENU for a general look at contents and to search for keywords, or from individual menus and screens when specific help is required.
If hardcopies of some help items are desired, any section can be printed from the HELP menu.
LogView is a Microsoft Windows 3.1 application which requires an 80386 PC or better. Four MB of RAM are needed to run smoothly, and a math co-processor is recommended, since LogView relies heavily on floating-point calculations. The installed LogView files require less than half a MB of hard disk space. Hardcopy output quality will depend on the printer.
GSC Acquisition of Borehole Geophysical data
GSC borehole logs are acquired with several probes at different logging speeds and sampling rates. The depth ranges and the data sampling intervals recorded for each logging run will therefore vary. It is standard procedure to plot logs from several probes beside one another, so the data for each run in a borehole for each parameter are stored as separate data files. The file detailing the geology for the borehole is also stored as a separate lithology file. LogView was designed to plot any combination of these data files, and to allow the lithology file to be plotted as coloured or patterned infill underlying the log traces.
Filename Extensions:
GSC borehole logging data are archived in several different formats and internal structures. Filename extensions are used by our software to determine the internal structure and format of the file. The first character of the extension determines the format of the data. ( A for ASCII and B for binary). The second character of the extension determines the internal data structure of the file. (Z for depth-value data pairs, Y for data over equal depth intervals, H for histogram and L for lithology). The third character is left to the user. (For example: 1,2,3.. for version number, or P for permanent, T for temporary, O for original.)
Data Formats:
Data files (Z, Y and H) can be either ASCII or binary format. Lithology is stored as an ASCII file. Logview has a built in utility to convert ASCII files to binary, which may be used to save disk space.
Internal Structure of Data Files:
All files have two 8 character titles at the beginning of the file. For GSC data, we have used these titles as log-title and units. Logview allows you to change the 'titles' that will be plotted. Depth and data values are single precision floating point numbers.
Z data files have data values at non-regular depth intervals, and consist of two 8 character titles, followed by records of pairs of depth and measured value.
For example:
TC
(CPS)
40.01 79.41
40.06 72.76
40.11 86.47
40.16 79.42
...
Y data files have data values at regular depth intervals, and consist of two 8 character titles, then a record with depth-start and depth-increment, followed by records of measured values.
For example:
TC
(CPS)
1.0 .2
79.41
72.76
86.47
...
H data files, or histogram files can be used for data such as assays which may be taken at irregular depth intervals. H data files have triplets of data values, and consist of two 8 character titles, followed by records of two depth values; a start and stop depth for each sample, and the measured value.
For example:
K
(%)
40.2 41.0 1.05
41.0 42.5 3.57
42.5 43.2 1.66
43.2 44.8 2.47
...
L data files, or lithology files contain the geological units, and consist of two 8 character titles, followed by records of lithology unit label, (enclosed in double quotes if it has embedded blanks), and depth start and depth end for the lithology unit.
For example:
GEOLOGY
&endash;&endash;&endash;&endash;&endash;&endash;&endash;
MTSD 40.00 45.20178
"GRN SCH" 45.20 50.13953
AMPHIB 50.13 63.39832
CONGLOM 63.39 67.97031
MTSD 67.97 83.66749
"GRN SCH" 83.66 89.91588
...
'Log display List' Files
LogView creates ASCII 'log display list' (LDL) files to save the attributes of a specific layout. The LDL file can be opened to reproduce the layout as originally designed, or to copy and edit it to produce a similar layout.
The specifications stored in the LDL file include a list of the logs to be plotted, along with an associated set of attributes such as line styles, titles, font sizes, filters, transforms, and clipping options for each displayed log. Also stored in the LDL file are the attributes for the layout as a whole. These includes details such as page titles, reference grid and depth axis options and paper size. Before a new layout is created, a printer and paper size must be selected. Paper sizes available will depend on the chosen printer, and portrait or landscape orientation may be used. If the paper size is changed while designing the layout, LogView will give you the option to resize the logs to fit the new paper size.
Depth axes, which can be placed anywhere alongside the other logs, and annotation files which contain objects (eg. a box with text) that are drawn on the layout, are also included in the LDL list of files.
There are a few items that can not be changed in any LogView menu, but may be edited in the LDL file. These include setting the depth axis label on the right instead of on the default left, matching the log title colour to the axis colour, setting colours for the reference grid and page titles, and setting a font for the entire layout.
Annotation Files
'Annotation' (LAN) files can be added to the list of files to be plotted for a particular layout. Size specifications in annotation files are based on sizes in mm on paper, so the type of printer and the paper size to be used must be known. By turning on 'smart cursor' in the options menu and choosing 'show paper position', it can be determined where to place the annotation. The following annotations can be added:
LINES, BOXES, ROUNDED BOXES, POLYLINES, POLYGONS AND TEXT BLOCKS.
The annotations can use different fonts, line styles and colours/patterns.
This feature is particularly useful if there will be several pages of log output with the same surrounding annotation on each. One LAN file could be created and added to each LDL file.
The specific formats of each annotation feature are detailed in the LogView on-line HELP.
Support Files
LogView utilizes two types of support files.
The first support file is referred to as the 'LITHOLOGY LOOKUP' file (LLL). This file relates the names assigned to geological units to colours and patterns to be displayed for these units, for the three colour tables used in LogView. One master file can be created with all geological units to be used or individual files can be created for each project area. LogView allows you to choose the LLL file you wish to currently use.
The second support file is a 'CUSTOM PATTERN FILE' (PAT). This file allows you to create your own custom patterns to add to those provided by Windows.
Windows INI File
LogView creates and updates a LOGVIEW.INI file in your Windows directory. This file keeps track of your current choices in LogView for features such as background colour, cursor mode, memory option and auto-redraw. It also records the path of your last used lithology lookup table file and custom pattern file. This is an ASCII file which can be edited.
LogView menus are typical Windows 3.1 menus, and are listed below, with details about some of the functions:
FILE MENU
CREATE NEW LAYOUT
OPEN LAYOUT
CLOSE LAYOUT
SAVE LAYOUT
SAVE LAYOUT AS
CHANGE PAPER
GO TO DOS
EXIT
EDIT MENU
DISPLAY LIST
DEPTH VIEWING RANGE
LAYOUT & COLOURS
LOG DETAILS
Y&endash;AXIS
Y&endash;AXIS DETAILS
Z & Y TRANSFORMS
LITHOLOGY LEGEND
PAGE TITLES
REFERENCE GRID
Z AXIS APPEARANCE
Z AXIS MARGINS
COPY TO CLIPBOARD
VIEW MENU
REDRAW
ZOOM
ZOOM BY RANGE
UNZOOM
OPTIONS MENU
CONSERVE MEMORY
CROSSHAIRS
SMART CURSOR
COLOUR TABLE
SUPPORT FILES
TOOLS MENU
CONVERT ASCII LOGS TO BINARY
HELP MENU
CONTENTS
SEARCH FOR
ABOUT LOGVIEW
EXAMPLES
This paper was originally presented in poster format, taking full advantage of colour illustrations. Although the content will be similar to that presented in the poster, some of the impact is lost in black and white.
Figure 1 is an example of multiparameter logs plotted for a single hole. Other features to be noted in this example are the TempGrad axis plotted at the bottom of the log, Low and High used for relative Density values, and a legend created in LogView with legend notes created in an annotation file.
Figure 2 is an example of the Gamma Ray logs for several holes plotted with the geology beside as well as underlying each log. The legend and other text features were created in an annotation file.
Figure 3 is an example of assays plotted beside logged parameters. Text has been added for description. (SGG Ratio is the ratio of the counts in a high energy window to those in a low energy window for a spectral gamma-gamma probe measuring a full energy spectrum. It can be used as a 'heavy element indicator'.)
Figure 4 demonstrates some of the transforms available for both depth and value data. The Gamma Ray log appears as unsmoothed data and then with two smoothing filters. The Resistivity log is presented on a linear scale, and then as a logarithm to base e and as a logarithm to base 10. The Density log is shown untransformed and then with a depth shift, and with a value transformation (multiplied by 2). Note also, in this example, that grid lines at standard depth intervals have been added. (Grid lines at specific depths could have been added instead.) Y-axis baselines (with lines, labels and both) are also shown.
Figure 5 displays the use of clipping, at the minimum for IP and at the maximum for Resistivity, A lithology fill under the log is also shown.
Figure 6 shows portrait plot orientation. Note also that the geology is labelled beside the lithology file, instead of a legend.
Figure 7 presents some of the many types of annotation which can be added to a LogView layout.
CONCLUSION
Within the Borehole Geophysics Section of the GSC, LogView has become a standard viewing and plotting package. Since it was felt that others could use this type of software, LogView, version 1.0, was released as GSC Open File 3055 in April,1995 and is available through the GSC bookstore.
GSC Open File 3055 includes the following, on one diskette:
The GSC is continuing to upgrade LogView, and when a significant number of new features have been added, the next version of LogView will be released.
ACKNOWLEDGEMENTS
The authors wish to thank D. Markarian for writing LogView under the guidance of J.A. Grant, J.A. Grant for initial and continuing recommendations on LogView and J.M. Carson for the critical reading of this manuscript.
REFERENCES
Geological Survey of Canada Open File 3055
LogView - A Microsoft Windows 3.1 application to view borehole log (geophysical and geological) data; D. Markarian, J.A. Grant and B.E. Elliott
Distributed through the Geological Survey
of Canada Bookstore,
601 Booth St., Ottawa, Ontario, K1A 0E8.
Tel: (613) 995&endash;4342 Fax: (613) 943&endash;0646
e&endash;mail: gsc_bookstore@gsc.emr.ca