Module: Projection Settings ()

Description:

This module displays as projected shapes the modules with the port projection connected to it. Connecting a module to a Projection Settings one can be done automatically by pressing the module's projection button

The projection applies only to the visualized shapes. Data modules won't be modified according to the chosen projection.

The whole bounding box of data coordinates must be expressed in geodetic coordinates :

• X coordinates degrees of longitudes in interval [-180,180]
• Y coordinates degrees of latitudes in interval [-90,90]
• Z coordinates meters

In order to fit those intervals the bounding box can be modified with the crop editor.

When using projection on a vector type module, the starting and the end point of each vector is projected. Then, a scale computed with the diagonal of the data set is applied.

It can happen that a vector data set is expressed in meters in a geodetic coordinate system. A transformation in degrees of longitudes/latitudes must then been done before projecting. This transformation is automatically done if :

• a parameter "units" with value "m/s" or "m s-1" is registered in the data parameters and
• The data is a NetCDF data or a parameter "coordSys" with value "GEODETIC" is registered.

Ports:

Parameters

General parameters for Proj4 projections.

Types

Available types of applied projection are :

• None: No projection is applied.
• Spherical: A spherical projection is applied. The radius of the sphere can be set.
• Mollweide: A Proj4 projection is applied. Proj4 documentation can be found here: http://trac.osgeo.org/proj/ .

  If bounding boxes don't fit the following intervals: X coordinates (longitudes) : -180 180 Y coordinates (latitudes) : -90 90 Projected shapes will appear cropped, unless zero longitude reference is specified.

Quality

Quality used when projection needs resampling. This port is only used for Ortho Slice and Slice modules. It controls the texture quality.

Radius

Radius used for spherical projection.

Z-factor

This factor controls the scale applied to the original z coordinates of the data. The computed radius of a point p(x,y,z) is given by the formula : computedRadius = z * z-factor + radius A negative z value can imply a negative radius.

LongitudeZero

This port controls the zero longitude reference when a Proj4 projection is selected. It can be used when the bounding box of the data is out of the interval [-180,180] for X coordinates.

It must not be used to switch the zero longitude reference when the bounding box is in this interval, otherwise visualisation artifacts will appear.