OR/15/046 Log view

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Wood, B, Richmond, T, Richardson, J, Howcroft, J. 2015. BGS Groundhog® Desktop Geoscientific Information System External User Manual. British Geological Survey Internal Report, OR/15/046.

The Log View window component is known as ‘Porcupine’, which is a sub-component of Groundhog that is designed to also operate stand-alone for other purposes. It can be found in the Log View tab of the workspace panel. It is a combined borehole viewer and editor. It is linked to the BGS SOBI and Borehole Geology databases. You can use it to:

  • Visualize borehole logs and customize their appearance
  • Make changes to borehole log interpretations (or create new interpretations)

At present you cannot use Porcupine from within Groundhog to commit changes back to the Oracle (BoGe) database — that capability is still being tested and will be released in the non-BETA version.

Displaying borehole interpretations

Viewing logs

Create a new blank document using the Create new document button OR15046fig109.jpg on the Porcupine toolbar and give the document a name. The document will appear as a blank canvas in the Porcupine desktop.


To add an interpretation to a document, right click on the interpretation in the dataset tree and select View log in document > [DOCUMENT NAME].


The interpretation will then be added to the document as a graphical log.


Setting Log Display Properties

General document display properties can be controlled using the check-options along the bottom of the document window. From here, the log headers, ornaments, descriptions and stepping can be switched on and off.


To edit the display properties for an individual log in more detail open the display properties dialog for that log by either double-clicking in the log's header at the top of the document, or by right- clicking on the log itself (make sure to right-click on the actual log interval column rather than the scale or description columns) and choosing Log properties.


Fields can be added to or removed from the header and a title and notes added. Additional options can also be selected to display extra properties in the description area of the log to include or exclude lithology and/or lithostrat as full descriptions and/or codes.

Setting Colours and Ornaments — "Symbology"

Porcupine will apply its own set of colours and ornaments automatically using the matching values in the workspace legend. For more details on setting up a colour legend, refer to the Workspace section of this manual.

The colour and ornament of an individual log interval can also be edited manually via the interval properties dialog, which will manually over-ride the automatically applied legend values. To open the dialog for a desired interval, double click on the interval box in the log. The interval properties dialog has two tabbed panels — choose the tab marked "Symbology".


The textures panel displays a list of any currently displayed ornaments.

NOTE: Porcupine only loads a list of texture files that match the codes currently present in the loaded log data. If the interval you are currently editing is using one of the currently loaded textures as its ornament the name label will be highlighted in red.


To display a full list of all available texture images in the library click the Import all textures from library button. This will load all available images from the texture_library folder.

Choosing and Applying an Ornament

To set an ornament for the interval, left-click on the desired entry in the texture listing — its label will turn blue to indicate that it is selected and the selected texture will appear in the preview panel in the lower right of the dialog. If you are happy with the selection, click Apply.

To clear the ornament texture from the interval click the Clear texture button at the top of the texture listing panel

Choosing and Applying a Colour

To set the colour on the interval, use the colour button in the upper right of the dialog to open a colour chooser dialog, select the desired colour in the dialog and click OK. The selected colour will be applied in the preview panel in the lower right. If you are happy with the selection click Apply.


Choosing and Applying a Stepping Value

To set the stepping class for the interval (between 1 and 5) use the "Grainsize" selector on the right of the dialog to choose a classification for the interval. A smaller value will result in a narrower graphical display for the interval. Note that stepping is not automatically displayed in the document window; to switch stepping on use the Show interval stepping check-box control along the bottom of the document window.


Viewing Borehole Scans

Scans of the borehole driller's reports are available on the intranet for many of the SOBI entries. With some boreholes loaded into the session, these scans can be accessed from within Porcupine via a link to the Intranet scans application. Individual scans can be accessed via Right-click > View scan on the borehole in the Workspace object tree (note that scans are attached to the boreholes, not to the individual interpretations belonging to the boreholes). Scans are loaded in a web browser by linking to the Intranet scans application.

NOTE: this function is not reliable on all machines and some scans might fail to load, in which case hit refresh in the problematic browser window. This is not a problem with Groundhog/Porcupine but with the browser and/or the PDF plug-in for the browser.

Editing interpretations

You can use Porcupine to edit your borehole interpretations and then save your Groundhog project to store the interpretation in XML data files. You can also use Porcupine to edit any borehole interpretation simply for graphical display if you wish.

Editing Log Intervals

Switch the interpretation into edit mode either via Right-click > Switch on edit on the interpretations' entry in the object tree, or via Right-click > Switch on edit on the interpretations' actual log or header in the document window.


If the header is visible its border will be displayed in red, and also a red "Edit Mode" label will appear above the log in the document window to signal that the log is currently editable. The interpretation label in the object tree will also turn red.

With the interpretation now in edit mode, double click on the interval to be edited to open the Interval Properties dialog. Under the Attributes tab, changes can be made to the intervals attributes (top and base, base bed code, lithology, lithostratigraphy and descriptive field) and applied by clicking the Apply button. Clicking apply at this stage applies the changes within the Porcupine session and does not save the change to the XML data files.



NOTE: Edits can only be made in the interval properties dialog if the interpretation is in edit mode. If the interpretation is not in edit mode the various fields will be greyed-out and non-editable.

Under the Symbology tab of the Interval Properties dialog, changes can be made to the colour, ornament, and stepping used to display the interval in the document. See above for more detail on the options under this tab.


Any values entered for base bed code, lithology and lithostratigraphy are dictionary-linked (i.e. they must correspond with an entry in the appropriate Dictionary for lithology or lithostrat — refer to the Dictionaries section of this manual for further details). The fields expect the dictionary CODES rather than the full descriptions because the full descriptions are often too long to fit usefully in a small text field. To see the full description for the code in each text field, simply hover the mouse cursor over the field — the full description will appear as a popup tooltip. Hover over the base bed, lithology and lithostratigraphy fields in the image above to see an example of the tooltips (works in most browsers).

If you do not know the exact dictionary code required for your coding you can use the Dictionary button OR15046fig123.jpg to open the Dictionary lookup dialog for the field. Begin typing into the Search field to see a list of matching entries in the dictionary. Check the desired entry and click OK to populate the code into the field. If you want to search by full description rather than just by the code, un-check the "Search by codes" option at the top of the dictionary dialog.


NOTE: The dictionary dialogs "remember" recently used codes and display these automatically when re-opened to save time when applying the same sub-set of codes repetitively across a number of borehole interpretations.

Changes can be made to the top and base depth values for the interval. The ft/in button alongside each of the two fields allows the depths to be entered in imperial — Porcupine will automatically convert them to metric and place them in the appropriate field.

If changes are made to the top and base values without consideration of any adjacent intervals, an overlap may occur. This will be shown graphically as a red border in the strat column for any intervals with overlapping problems. To resolve the overlap the top and base values of adjacent intervals will need adjusting or, alternatively, overlapping intervals can be deleted and removed completely:


When an interpretation has been modified the borehole and interpretation icons will change in the dataset tree to indicate that changes have been made (a pen icon appears alongside the standard interpreter icon). Remember — edits are only held in the Porcupine session and not automatically applied back to the data files or the Oracle database. If Porcupine is closed without committing edits back to the database then the changes will be lost. For more detail on committing changes back to the database refer to the later section.


Inserting and Deleting Intervals

New intervals can be inserted into an interpretation by right-clicking on an existing interval and selecting Insert interval:


This will open the Interval Properties dialog allowing the attributes and symbology to be set for the new interval. The top depth value of the new interval will be set using the base value of the clicked-on interval (i.e. the new interval will be inserted below the clicked-on interval). Unless the new interval is being inserted at the base of the interpretation or into a gap in the interpretation, an overlap with adjacent intervals will occur. Overlap situations are highlighted by a red box in the strat column. Overlaps can be easier to see if log stepping is enabled (compare below images).


To resolve the overlap the top and base values of adjacent intervals will need adjusting or, alternatively, overlapping intervals can be deleted and removed completely. Double-clicking on an overlapping region will present a selection dialog allowing you to decide which of the two overlapping intervals to change in order to reconcile the overlap. Check the interval you want to edit and click OK.


Edit the depth values as appropriate to remove the overlap and click Apply > OK:


To delete an interval from the interpretation, right-click on the interval to be removed and select Delete interval:


This will create a gap in the interval, which will need to be filled by either inserting additional intervals or by editing the top or base values of the adjacent intervals:


Gaps can also be auto-filled by right-clicking on the interval above the gap and selecting Autofill gaps. If above rockhead the autofill will apply a generic DRFTU code (generic superficial/drift code from the Oracle dictionaries) and if below the rockhead a generic ROCK code will be applied.



Data sets can be filtered interactively within Porcupine. The filters are under a right-click (on the data set entry) > Filter dataset.

Remove Boreholes Without/With Logs

These two options allow you to remove logs without logs (interpretations), or remove those with existing logs. The first is useful to filter out borehole records with no downhole data, the second is useful to see which borehole have yet to be interpreted.

Cascading Interpreter Filter

If the name of the intepreter is available within the borehole dataset, this presents a list of interpreter id’s (i.e. geologist names or drillers names) on the left. Click on an entry to highlight it and use the Copy to selection >>> button to copy it to the selection list on the right. Build the selection list up in order of preference, with the preferred interpreter at the top of the list. To re-order the list, highlight an entry and use the Move up and Move down buttons. When you are happy with the selection click Apply.


The filter will use the list to filter the data set in Porcupine. For each borehole it will look for your preferred interpreters in list order — if the first one is available it will be used, otherwise the second, otherwise the third etc... If a borehole has no matching interpreter it will be deleted from the data set completely.

Cascading Project Code Filter

If the name of the project is available within the borehole data, this operates in the same way as the cascading interpreter filter, but uses the CONTENT_CODE field (a.k.a project name field) of the interpretation for the filtering.

Cascading Interpreter + Project Code Filter

This operates in the same way as the cascading interpreter filter, but filters by unique combination of INTERPRETER and CONTENT_CODE.

Drilled Depth Filter

This allows you to filter by drilled depth and can be applied either as a more-than or less-than filter depending whether you are interested in only deeper or shallower boreholes. The settings below would retain only those interpretations that have a drilled depth of 25 m or more.


Lithostratigraphy Filter

This allows you to filter based on lithostrat codes. The unique list of lithostratigraphic coding is presented on the left and can be copied to the select on the right by selecting the entry and using the Copy to selection >>> button.

The order of the list on the right is not important, so there are no sorting options. The list is not cascading. Porcupine will use an OR test on this list when deciding whether to retain an interpretation — in the example below the filter would retain all interpretations that have CHALK GROUP or CRAG GROUP or LOWESTOFT FORMATION coded anywhere in them.


Confidentiality Filter

This allows you to filter on the confidentiality code of the borehole entry, if such a field is populated in the borehole data. There are 5 numeric codes:


You can find the confidentiality of a particular borehole by hovering over it in the dataset tree and reading the tooltip that appears. Also, if a borehole is level 2 or 3 you will see an amber asterisk to the right of the log icon — if it is a level 4 or 5 the asterisk will be red.


The filter gives you the option to remove levels of confidentiality from the dataset. Simply select the levels you wish to retain and click Apply. For example, if you do not want any confidential boreholes in your dataset, only select “1 — NO CONDITIONS APPLIED (NON-CONFIDENTIAL)”.

Filter Chaining

The filters can be applied successively against the same data set to refine it. For example, if you were only interested in having borehole interpretations with a drilled depth of more than 10m which have CRAG GROUP coded in them preferably by HBU but failing that by RTE then you could apply three successive filters to achieve this.

Viewing curve logs

How to load Well Log data into the workspace is described under the Interoperability section of this manual. Once the data has been loaded, it can be viewed graphically using the Log View. Each set of measurements is displayed within its own Log Track, but several Log Tracks can be viewed alongside each other within a Document. One or more Documents can be loaded into the Log View and can be viewed by clicking on the tab with the document name.

To view a set of Las file measurements, right click against the measurement heading in the tree structure and select View In Porcupine Document > New Porcupine Document. If a Porcupine document has already been created, this can be used as an alternative to creating a new one.


If a new Porcupine document is created, it is given a name here.


Once the document has been created it can be viewed by clicking on the Log View tab.


Details of the Las file are shown in the document. The Las file shown below does not have any measurements until after 15 metres, so nothing is shown here.


If the scale is changed to 1:500, measurements can now be seen.


A scroll bar allows the full log to be viewed.

At the top of the document, the heading details can be seen. These vary, depending on the source of the Well Log, but will normally include location and depth details. Double-clicking in the heading area, enables curve log settings to be changed, via a dialog box.


The information that is viewed in the heading can be enabled or disabled with a tick in the checkbox. It is also possible to change the colour of the curve, which has initially been set randomly, or to show grid lines, flip the diagram so that it is a mirror image of itself or show the curve using a logarithmic scale.


Las file data can be viewed alongside other borehole data.