Querying DTMs

The DTM options from the DTM Query Menu allow you to query the triangles in a DTM as well as their relation to other DTMs.

Query DTM Triangles

The DTM Triangle option allows you to query a series of DTM triangles.  When selected, you will be asked to indicate a location in the DTM to query.  The current lock mode can be used to be more specific about the location of the query co-ordinates.  When a DTM triangle is found, a report view is displayed show you the information about the triangle and its associated properties.

The information displayed includes the co-ordinates of the apexes used for the triangle, the plan area of the triangle, the slope area of the triangle, the gradient of the triangle and the direction of that gradient going down.  A further set of co-ordinates shows the query point with the height being interpolated from the triangle.

The DTM Differences option allows you to query a triangle and display the height of the query co-ordinates in DTMs in the current backcloth.  The operation is the same as the option above.  For each DTM in the backcloth, the interpolated height will be displayed together with the difference from the current DTM to the backcloth DTM.  A positive value indicates that the current DTM is above the backcloth DTM.

Querying Boreholes

The DTM Borehole option allows you to query borehole information from a series of associated models.  To query a borehole, you should be in the model called “Ground Level” which was created when the borehole model was imported.

You will be asked to indicate the borehole point and n4ce will search the associated models to find the same borehole in the other strata. A dialog showing the strata information will then be displayed as shown below.

The Surface column lists the names of the models associated with the ground-level survey.  The remaining three columns show the level of the top of the next model, the depth from the ground level to that model and the thickness between the models.

Querying CAD Elements

The CAD Element from the DTM Query Menu allows you to query CAD elements that are in the current backcloth. You will be asked to indicate the CAD element concerned and a report view containing the attributes of the element will be displayed.