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Package gov.nasa.worldwindx.examples.dataimport


See: Description

Package gov.nasa.worldwindx.examples.dataimport Description

This package contains examples that show how to import imagery and elevation data and how to use it to create layers, renderables and elevation models. Since this type of data is typically in the form of a raster, World Wind calls it raster data. World Wind can import many formats of raster data, including but not limited to JPEG, JPEG-2000, PNG, and DTED, and GeoTIFF for both imagery and elevations. Data can be imported from a local or network disk, or in many cases directly from a network URL. This overview describes the import process and identifies example programs showing exactly how import is done.

Note that World Wind can also draw data incrementally from web services such as WMS and WFS, but this overview covers only importing bulk data from files or streams.

When importing data, World Wind reprojects it to the WGS-84 datum and latitude, longitude coordinates, which is World Wind's internal coordinate reference system (also known as EPSG:4326).

In addition to some internal importer classes, World Wind uses ImageIO and the open-source GDAL library to read and potentially reproject data on import. This enables World Wind to import a very wide range of image formats and projection types. It also makes it possible to import very large data sets composed of many files.

Here is a list of the most commonly used formats supported, see for the full list:

Importing vs. Installing

Raster data can be imported for just the current session or installed for permanent availability.

Installing Imagery and Elevation Data

Installing data adds it to a permanent location on the local computer. It's installed in a way that facilitates rapid access by World Wind. Unlike the World Wind cache, installed data is never automatically deleted. Applications may specify the installation location, but by default the location is:

These locations are peers to the World Wind cache directory.

Installed imagery is typically displayed as a TiledImageLayer. Elevation data is typically used to create an ElevationModel. As these classes run, they automatically create sub-regions and reduced resolution versions of the data in order to optimize performance. This information is saved permanently in the installed-data location. Depending on the size and complexity of the data, World Wind may also create one or two levels of reduced resolution data during installation.

When installing data, the source data can be copied to the installed-data directory or left in its original location. If the data is not copied, it's of course necessary that it be available and accessible in the original location when subsequently needed. The data location is captured in a configuration file stored in the installed-data directory for the particular data set. The examples InstallImagery and InstallElevations shows how to use this file to create a layer and an elevation model, respectively.

Data Installation Examples

The example InstallImagery shows how to install imagery and use it to create a TiledImageLayer. The example InstallElevations shows how to install elevations and use them to create an elevation model. Both classes are heavily commented to describe their operation.

Importing Imagery and Elevation Data for One-time Use

It's often the case that data is needed only during a current session. In this case the data should be imported but not installed. The ImportImagery and ImportElevations examples show how to import data and use it to create a SurfaceImage for imagery and an ElevationModel for elevations.

Deploying Data Import Capability

See the package description of for data import deployment instructions, including deployment with Java Web Start.

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