Geospatial Interface Settings

The Geospatial tab allows for conversion of models in a geospatial coordinate system. Here various attribute information about the model data can be specified. This is somewhat related to operations on the Grid tab, and the Interface Settings Color Mapping and Elevation tab.

The Geospatial Geospatial tab user interface is shown below.

Geospatial Input Units:

Coordinate System

The Original Orientation ["Right Hand (Z+Up)", "Right Hand (Y+Up)] selector applies a transformation on the 3D coordinates to a new orientation. The 3D PDF view coordinate system is "Right Hand", so incoming data is normally assumed to also conform to "Right Hand" coordinate assumptions.

This option selects one of two possible coordinate space orientations for the 3D view. The default is Z+Up, which is the normal Adobe Reader default view setting. In this orientation, X coordinates in a default home view will be along the horizontal left-right direction on screen, while the Z coordinates will be vertical top-bottom of screen view. The Y axes will be shown as depth into the screen, along viewing direction.

If the Y+Up option is selected, then the PDF is generated with an additional 90 degree scene rotation, by means of a root node level transformation matrix. In this modified orientation, X coordinates in a default home view are still along the horizontal left-right direction on screen, while the Y coordinates will be vertical top-bottom of screen view. The Z axes will be shown as depth into the screen, along viewing direction. You may observe this additional node in the 3D PDF viewer model tree.

The original orientation option setting does not change to Left hand coordinates or change the sign (directional meaning) of any axis. The selection of Z+Up or Y+Up affects all the scene's 3D contents, including axes, labels, animations, layers, etc, from any of the available interfaces and file types. It is not restricted to use with Geospatial data, however the menu is placed on the Geospatial tab because that is the most frequent use. The Mouse3D probe menu option reports the original coordinates, before rotation.

Prescale Factor, X Axis, Y Axis, Z Axis allow for special case where the input data is already pre-multiplied by some artificial scale factor. If this is known, then value can be entered here. This will allow Probe, Z Scaling, and other operations to correctly interpret the input data.

 

System - Coordinate System selected from Input, Cartesian, Geographic, Projected, Custom WKT conditions the input data according to the coordinate system used. If one of Geographic or Projected is selected, then a further menu appears for GCS (Geographic) or PCS (Projected) coordinate system specifications. If Input, then this setting will attempt to obtain the coordinate system from the input data where available. For non-geospatial applications, such as CAD or Engineering, the automatic input mode will not assume any coordinates, or the Cartesian (x,y,z) mode can be specified.

In Geographic or Project, a selection list of standard EPSG and WKT entries are provided for selection. If the designed coordinate system is not available in this list, a Custom WKT can be specified.

The coordinate system list can be very long to navigate. The blue/green icon at the right can be used to expose a search string box. Any text or numerical value can be entered which will subset the long list to only those entries containing the typed string.

Geospatial Image

Alternatively an image file can be selecting using Use Image File as Texture. Texture images are mapped fully onto the grid surface, so aspect ratio and alignment boundary must be arranged before use. For Panoramic 360 images, this menu is where the image file (JPEG, etc.) should be inserted.

A Georeference World-File, .jpw, tfw, or PROJ file, etc., if placed next the imported image, with exactly the same base filename, should be recognized and loaded. This extra world file specifies the geographic coordinate system for the image, and allows draping over georegisted grids, without requiring exact extent fitting. You don't need to explicitly load the world file, it will be picked up automatically when loading the image file.

If specifying a GeoTIFF image, the coordinate system in the header of the file will be used.

Enable High Resolution Textures option can be checked in order to increase the resolution and fidelity of the image, at the expense of larger file size and potentially less interactive performance. The Adobe Reader 3D display sub-system, for instance imposes a cap on possible texture image sizes. With this option in the default disabled state, texture images above this threshold are resampled to lower resolution, smaller images to retain good interactive performance and smaller file size. If this option is checked, then high resolution images above the threshold do not get re-sampled, and go through to the 3D scene. Note that texture splitting may be another option to achieve high quality images, by a method which splits up meshes and images so that each individual texture image is smaller, to avoid display-time re-sampling. Further note that where images are directly referenced from an external file, such as OBJ+JPEG this resolution re-sampling is avoided, and the original image encoding is used directly.

 

Default view generation is recommended to be set to "Geospatial" rather than "CAD", assuming the datum and coordinate system is North-aligned.

North Compass -A North direction indicator is available on the Scene Axes tab.

Texture Options

When an input image is too large and should be reduced, it can be subsampled to 1/2, 1/4... using the Divider parameter.

When the image used as a texture is larger than efficiently handled the viewer, a splitting algorithm may be enabled to tile the texture image and create sub-objects in the geometry tree to hold each tile mapping. Several splitting schemes are supported.