Creating Resolution Pyramids

A resolution pyramid stores a series of increasingly reduced resolution representations of a raster layer. Having a resolution pyramid enables rapid display of the raster at various resolutions, by allowing TerraBuilder to fetch only the data at the specific resolution required for display. When you are zoomed out of the layer and don’t require a high resolution representation, TerraBuilder can display a reduced resolution that draws faster. When you zoom in, levels with finer resolutions are drawn but performance is maintained because successively smaller areas are being drawn.

Although layers will display in the layer windows in the available resolutions, even if other resolution levels don't exist, TerraBuilder requires sufficient resolution levels for each layer to create the final 3D terrain output (MPT). If a layer has no resolution pyramid or only an incomplete or insufficient one, TerraBuilder creates it automatically before creating an MPT file. When publishing a project for streaming using DirectConnect, the DirectConnect project can be optimized by creating resolution pyramids for layers that do not have MPT resolution pyramids.

After a resolution pyramid is built for a layer, it is accessed each time the layer is viewed. If certain settings such as compression are changed for a layer, its resolution pyramid may also require updating. You can select the format MPU/MPT and format settings (compression) for the resolution pyramid in the Properties Sheet for each layer.

Some source file formats already have a built-in resolution pyramid. When you add a source to a project, TerraBuilder looks for an existing resolution pyramid, first in the source path directory, and then in the list of directories of the project. If multi-resolution data is available for the source for all resolution levels until the Max Visible UPP (maximum UPP in which the source is still visible) defined for the source, TerraBuilder marks the source as having a pyramid. The status of each layer's resolution pyramid (Complete, insufficient, no pyramid) is displayed in the Info column of the Layer List. This column contains one of the following icons:

pyr.gif - Layer has a sufficient resolution pyramid

  - Pyramid incomplete

nopyr.gif - No resolution pyramid  

 

Create Resolution Pyramid and Create Resolution Pyramid for All Layers create resolution pyramids, using the MPT or MPU formats, for layers that do not have resolution pyramids sufficient for the project. If resolution pyramids are not created, TerraBuilder creates them automatically before creating an MPT file.