Canyon

Canyon is a general digital data modelling package. It is entirely integrated in Cadics and can be used with other modules of Cadics, such as the road and rail design or the drainage package to create the ground model for the project or to integrate the entire project into a ground model to create photorealistic pictures.

Data

Canyon can read data in (points, structure and break lines) in all common formats. It is also possible to define new data formats to adapt the program to specific applications. It is directly interfaced with the Topics database and indirectly with a large number of other surveying packages.
Canyon can also read in data in DXF and similar formats to create a ground model automatically.

Aerial survey data

Data produced from the numerical restitution of photogrammetrical flights can be read directly into CANYON (points and lines). It is then possible to define the style of each layer and which layers have valid altitudes for the ground model. Various control functions allow the quality and coherence of the input data to be tested.
Certain layers (buildings, lakes...) can be defined as dead zones which are excluded from the ground model. Others, which represent the edge points of rooves can be used to recreate the shape of buildings automatically for representation in cross-sections and perspective views.
Photogrammetric data: layers colours and line types are attributed automatically from a tabular definition. A digital ground model is automatically extracted from the layers representing the ground, rooves and dead zones. canyon1

Ground modeling

There are two families of methods to model a surface on the basis of discrete point information:

Statistical methods, in which the altitudes are first averaged within a predefined matrix.
Direct methods, in which plane or curved triangles are created between the points in the model.

Statistical methods are useful for cases where non-representative data may be present, without any criteria to eliminate them to produce a “clean” database. This is often the case in geology, climatology, etc.). The more recent direct methods (TIN or raster) are better adapted to modelling natural geographical models and buit-up areas:

The interpolated altitude of a point is always exact.
Zones with very different point density can coexist within the same model.
Smoothed surfaces can coexist with sharp breaks in continuity (road edges, walls, buildings).

Model of a dam showing the old and new states recorded by sonar.
Canyon uses the Delaunay triangulation method, giving the best possible interpolation quality. Break lines, structure lines and edges can be defined to guarantee the best possible conformity between the model and reality. There is no practical limit to the number of models or their size. Each model may be made up of one or more layers.

Construction

Models can be combined, added or subtracted. Part of a global model can be replaced by another model. Surfaces generated by other modules (for example Road design) can be integrated into existing models. Volumes (cut and fill) can be calculated by comparison.
If only a part of a large model is useful for a specific task, CANYON allows a submodel, defined by a polygonal line to be used.

Editing functions

Whatever their origin, (points, aerial survey, road design...) ground models can be modified or completed manually at any time. Functions include:

Adding new points, lines or triangles.
Deleting points, lines or triangles.
Modification of the coordinates of points or of the altitudes of points or groups of points.
More sophisticated functions, such as cutting or fitting of lines, intersections, merges, etc.
Information on the data, altitudes or the slope at any given point can be displayed.

Modifications can be made definitive or abandoned at any given time.

The result of a project or another model can replace part of a model. Links between the models are created automatically (green triangles). Contour lines allow the flow of rainwater on roundabouts or large junctions to be checked.

Printouts and drawings

All data and results contained in a CANYON database can be printed or exported in a simple ASCII format. The graphic representation of the model’s data can be completed by the numbers and/or the altitudes of the points.
Contour lines can be smoothed by interpolation of the surface (very high precision), by the use of splines (very fast but less precise) or by a combination of the two for optimal rendering quality.

Isopachytes represent the difference between two layers or the thickness of one layer in the form of contour lines. Cross-sections can be generated at any point of the model and can represent one or more layers of one or more models.

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