Table of Contents

Pre-Processing Data using Construo

Construo, the Crusta data pre-processor, processes DEMs (topographic data), imagery (Satellite, Aerial, etc - basically anything with three 8bit bands) and scalar layers (difference maps, slope maps, etc - basically anything with a single scalar band). The processor accept numerous types of data (TIFF, ArcGrid, etc - anything that is supported by the GDAL library).

Before getting into the details on how Construo is used it is important to understand why it is even needed. The high-quality data visualization provided by Crusta in real-time is possible due to optimization in how the data is organized. Crusta assumes that a globe is partitioned into 30 patches which are in turn refined into a multi-scale hierarchy as needed by the spatial resolution of the visualized data. The set of these 30 hierarchies, combined with a meta-data descriptor, form a Crusta globefile. Construo is the tool used to build globefiles from traditional digital terrain data.

Construo Options

Construo can be run from a Terminal window. For a printout of how construo works, you can simply type:

construo

which displays all the options:

Usage:
construo -dem | -color | -layerf <globefile name>.globeFile
         [-offset <scalar> | -noOffset]
         [-scale <scalar> | -noScale]
         [-nodata <value> | -defaultNodata]
         [-pointsampling] [-areasampling]
         [-settings <settings file>]
         <input files>

IMPORTANT - Creating a Crusta globefile is like painting. At first you need to paint a base layer and then layer other paint on top that improves the painting. Thus, when processing a Crusta globefile with different resolution data - the input file order is important. First specify the coarsest resolution data and then the medium then the finest resolution (e.g. Blue Marble –> Aster –> LiDAR).

Mac OS X

The Construo.app application bundle replaces the command line usage. note: The Crusta.app and Construo.app bundles must both reside in the same folder for Construo to work. Please follow these steps to build globefiles:

  1. Double-click the Construo.app icon to bring up the configuration window. Here you must specify the type and name of globefile to produce. Please see the options -dem, -color and -layerf above. Click “Done” once you have completed the specification of the output globefile.
  2. Drag the desired input files on the Contruo.app icon. These data will be added to output globefile specified on the previous step.

You can edit how Contruo interprets the input files by clicking “Parameters” on the configuration window. The options are specified above. Edits are saved and reused whenever files are dragged onto the icon, so please make sure to setup the parameters accordingly.

Construo Examples

For the examples we provide the command lines and assume that ouput globefiles should be placed in the /Data/Processed folder and all the input files can be found in /Data/Raw

construo -dem /Data/Processed/topo.globeFile /Data/Raw/dem0.tif /Data/Raw/dem1.tif
construo -dem /Data/Processed/topo.globeFile /Data/Raw/dem2ArcGrid
construo -color /Data/Processed/color.globeFile /Data/Raw/color/*.tif

Other Notes: