How to extract and display gradient information from a DTM surface in Surpac

A function within the Structural Suite of Surpac allows for the extraction of gradient information from a dtm surface.

The function drops a grid of points at user specified separation, over the surface. At each of these points, the dip and dip direction of the grid square is calculated and this information recorded. This means that surface slope data can be analysed and used to help with decision making on critical issues like safety protocols, ramp placement, or berm creation.

Additionally, it would be possible to make a comparison between datasets produced as a result of separate surveys taken over time for stability issues. The function will output either a .csv or .str file. The user can then chose to display the string file, or import the csv to a drillhole database for more display options using other Structural Suite functionality.

This blog post shows the steps needed for the database option.



Display your dtm file in the graphics window and from the menu select Database>Structural Suite>Generate dtm gradient data.

Select the trisolation by clicking on it in the graphics window.

In the form that appears, select the grid spacing you wish to use. This can be visualised to aid in selection.

Select the output file type – in this case we will select .csv and specify the filename to be used. It is advisable to check the box to include column headers.




The result from this will be a csv file, saved to the working directory, with the following columns: sample ID, x, y, z, dip, dip direction.

Please note that Surpac uses y,x,z for 3D points, and that therefore these columns will need to be specified carefully during the import process.



Create a new table for the database (database>database>administration>create table). The table type should be “discrete” and optional fields for “dip” and “dip_direction” should be created.

Don’t forget to make sure that lower and upper bounds make sense for the information being recorded.




Once the table has been created, the standard import process for data to the database can be followed.

After the import of the data, we can use the data visualiser to display the information taken from the dtm.

Select Database>Structural Suite>Data Visualiser and complete the form.



In this example, we will make selections such that arrows are displayed showing the dip direction, with colours showing dip ranging from blue (shallow) to red (steep).

By changing the specifications made in the data visualiser forms, we can change the type, size and colour of the icons used to display out data if we wish to do so.



The symbols displayed are placed in a new layer within Surpac, and can therefore be saved as a .str file for later use.



GEOVIA Surpac Structural Suite is a feature-rich module available now. For more information, please contact your local GEOVIA representative or email:




Chris Bates

Mining Knowledge Consultant (Geology), GEOVIA at Dassault Systèmes
Chris Bates is part of the GEOVIA Center of Excellence in EMENA. As an experienced Geologist, Chris previously specialized in exploration geology with a focus on gold exploration in Guyana, South America. Chris has also worked on resource estimations for phosphates, coal and precious metals as well as data review validation and management. Chris specializes in GEOVIA Surpac, GEMS and MineSched and is based in Coventry, UK.