Understanding the geology below cities is increasingly important for development
and decision making.
BGS creates urban geological models for some of our major cities
to provide a three dimensional characterisation of the rocks and deposits
that make up the upper tens to hundreds of meters of the ground.
These models provide regional scale information that can be used
to guide the planning process and develop conceptual ground models.
BGS is now making key models available for free for the first time
via a new interactive tool in the BGS GeoIndex.
The GeoIndex is our shop window and provides access to a wealth of BGS
geological datasets, including digital maps and borehole records.
In this video, we will show you how to use the new Urban
Interactive Models tool to create virtual boreholes,
cross-sections and horizontal slices through the geological models,
revealing the key geological units underground.
To access the urban interactive models tool
open up the BGS GeoIndex in your browser
and click on the Add Data button.
In the data list, search for the 3D geology section
and select the Urban Interactive models tool. Close the data list
and in the main screen, you will see the urban interactive models layer
in the table of contents and the toolbar at the top of the map view.
The available models are displayed on the map.
Currently, Glasgow, Cardiff and London are included.
In the toolbar,
you can toggle on the map top layer to view the geology at the ground surface
and select a model to zoom into your area of interest.
Once you have located your area of interest, you can start to investigate the model.
To create a virtual borehole through the model,
click the borehole button on the toolbar.
Clicking once within the model area will bring up a link in the toolbar,
which says Open Virtual Borehole.
Clicking on this link will open a new browser
window displaying the virtual borehole log you have created.
The page provides links to further information resources
about the geological model and access to the related BGS services.
A downloadable version of the log in a standard format PDF can be accessed
by clicking on the PDF button in the top right of the page.
To draw a cross-section, we need to go back to the model in the
GeoIndex page and click the cross section button. To draw a cross-section
we need to click once in the model area to start drawing a section
and then click again to finish the section line.
You will notice that the cross sections
are limited to straight lines up to five kilometers in length currently.
If your line goes beyond five kilometers, the top toolbar will turn red
to indicate that your section is too long. In the toolbar.
click the Open Virtual Cross Section link to open the cross section
in a new window.
The section display can be adjusted by first specifying a cutoff elevation
and clicking the update button.
Once the cutoff
elevation has been adjusted, you can adjust the vertical exaggeration.
Hovering over the question mark next to the entry box
will show you the range of vertical exaggeration values available
for the given section length and cutoff elevation.
Enter your preferred value and click the update button.
Just like the borehole log, you can generate the downloadable PDF
version of the section by clicking on the PDF button in the top right of the page.
To create a slice through the model,
click the horizontal slice button on the toolbar.
This tool allows you to draw a square area
in the model and specify a depth of interest for the slice.
Using the left mouse button, click once and hold to place the centre of your
square and drag away from the start point to expand the slice area.
When the desired coverage is reached, release the mouse button.
You will again notice that slice areas are limited
to a range between a quarter of a kilometer and ten kilometers square.
In the dialog box that
appears, you can specify the depth or elevation of your slice.
You can choose to display a depth below the ground surface or
an elevation relative to ordnance datum.
You can also select the resolution of the image,
higher resolutions will take longer to generate.
Click Continue and then click on the Open Horizontal Slice
link in the toolbar to open the slice in a new browser window.
The depth or elevation of the slice can be further adjusted in the page
using the input boxes, and a downloadable PDF can be generated
via the PDF button.
We will be continuing to develop and improve this tool,
so please do help us make sure it meets your needs by providing feedback
via our Enquiries service, citing urban interactive models tool in your email.
If you'd like to be part of a user forum to discuss future
developments to the tool and other 3D data services, please get in touch.