THE TruEarth® 1km LEGACY.
In 1998, TerraMetrics debuted its first global image dataset called "TruEarth® 1km." The TruEarth® 1km product was the first cloud-free global Earth image based on actual landcover coloring. TruEarth® 1km imagery was unsurpassed in color, luminance, and ground feature accuracy... a remarkable and stunning visual portrayal of our planet.

Fast forward to 2005 and the release of our TruEarth® 15-meter global dataset... wow, the world has gotten so much closer!

Nonetheless, TruEarth® 1km lives on in our hearts. This page serves to keep the TruEarth® 1km legacy alive. In fact, the complete TruEarth® 1km imagery collection is still available and perfect for those "crash-zoom" animations from outer space.

PRODUCT FEATURES.
At its full size, the TruEarth® 1km image is 43,200 pixels wide by 21,600 lines high with a nominal ground resolution of 1 kilometer x 1 kilometer per pixel (about 0.6 mile x 0.6 mile/pixel). TruEarth® 1km imagery is separated into two discrete categories: color base imagery and collateral grayscale imagery. The color base images are full-color 24-bit RGB images, while the collateral grayscale images are 8-bit grayscale images. All TruEarth® images are delivered in the .TGA image file format because of its simplicity and commonality across platforms and applications. 

COLOR BASE IMAGES.
TruEarth® 1km color base imagery comes in three primary forms, each of which has the identical land imagery combined with one of three ocean portrayals.

Natural Ocean
The natural ocean color TruEarth® 1km image shows the ocean as it appears to the eye. Natural coloring derived from phytoplankton concentrations and other ocean-specific datasets ranges from the natural ocean blues through the greener phytoplankton-rich regions. The TruEarth® 1km natural ocean image is the best choice for most productions involving the Earth as seen by a human observer. TruEarth® 1km color base imagery includes terrain sun shading from an Easterly-direction which naturally highlights landform features, providing a deep richness to the imagery.

We developed a second TruEarth® 1km natural ocean color balance that specifically matches higher-resolution imagery such as Landsat7 datasets. Referred to as the "TruEarth® 1km natural-color local balance" version, the imagery incorporates a local brightness balancing technique that brings out additional detail in otherwise darker areas of the imagery. The local balance version of the natural color imagery is sometimes preferred to the original natural color image for certain production applications. 

Clear Ocean
The clear ocean color TruEarth® 1km image shows the ocean floor relief as though the ocean itself were transparent. This unique view of the Earth shows off the drama of the ocean floor with imagery derived from actual bathymetric measurement data. The TruEarth® 1km clear ocean image is best for productions relating to Earth physical sciences where visualization of the ocean floor can be just as important as the landforms.

No Ocean
The no-ocean color TruEarth® 1km image shows only the landforms of the Earth; the ocean areas are black. Combined with the collateral grayscale mattes (see below), the color no-ocean image can be composited with any external ocean imagery or textures desired by the user. The TruEarth® 1km no-ocean image does not show north or south polar ice forms, like the natural and clear ocean image types, only actual land masses.

COLLATERAL GRAYSCALE IMAGES.
Thirteen grayscale images make up the set of TruEarth® 1km grayscale collateral images. These images round out the color base imagery by providing additional resources to the user. The thirteen images include two shaded relief maps, a night lights map, an elevation/displacement/bump map, five geo-political boundary maps, and four mattes.

Shaded Relief Maps
The shaded relief images come in two forms: one that is pure shaded relief terrain and the other that has ocean, lake, and waterways portrayed in black. These images can be used as simple texture maps showing the Earth's terrain without any color attributes.

Bathymetry Shaded Relief Map
The bathymetry shaded relief image provides shaded relief of the global sea floor. The bathymetry shaded relief is available down to the 4km-per-pixel resolution due to source data availability. Like the land shaded relief images, this images can be used as simple texture map showing the Earth's sea floor without any color attributes.

Night Lights Map
A truly cool image, the TruEarth® 1km night lights image shows the lights of the world as they appear at night. This grayscale image can be color-tinted and mixed with any of the TruEarth® 1km color base images to create compelling nighttime shots. Also, the night lights image is indicative of the Earth's population centers and can be used for visualizing populated locations of the world.

Elevation/Displacement/Bump Map (8-bit grayscale and 16-bit DEM versions)
The TruEarth® 1km elevation image represents terrain elevation with black equal to the lowest elevation and white equal to the highest elevation. This 8-bit grayscale image can be used as a displacement map to displace a planar or spherical grid of vertices to conform to the true ground terrain, thus creating a 3D terrain model. One of the TruEarth® color base images can then be used as a texture map applied to the terrain model. Similarly, the elevation image can be used as a bump map to create terrain-based shading on the no-relief versions of the color base images (see above).

The TruEarth® 1km elevation image is also available in a 16-bit per pixel format. The 16-bit elevation image provides full elevation resolution to 1-meter height increments. Each elevation pixel is a "short" data type (signed 16-bit integer) providing positive and negative height values. This version of the elevation/displacement/bump map image is perfect for high-resolution flight simulator and visualization applications.

Bathymetry/Displacement/Bump Map (8-bit grayscale and 16-bit DEM versions)
The TruEarth® 1km collection includes bathymetric elevation data of the global sea floor in both 8-bit grayscale and 16-bit DEM formats. The bathymetry datasets are available down to the 4km-per-pixel resolution due to source data availability. This dataset can be combined with the terrain elevation dataset to provide complete elevation coverage for both land and sea areas.

Geo-political Boundary Maps (Coastal Only)
The TruEarth® 1km geo-political boundary images provide an additional layer of information illustrating coastal, country, and internal political boundaries. Boundaries are composed of single-pixel-wide lines in white against a black background. Included is a coastal-only version (shown at right) and four additional versions (see below).

Geo-political Boundary Maps (Including Coastal)
The primary TruEarth® 1km geo-political boundary images contain geographic coastal boundaries and additional political boundaries, including: 1) country and internal; and 2) country-only versions. "Country" boundaries comprise international boundary and separation lines; "internal" boundaries comprise state and province lines.

Geo-political Boundary Maps (Without Coastal)
Like the geo-political boundary images with coastal boundaries, the non-coastal versions provides the option of letting the base imagery convey the coastline visually. The two non-coastal images include: 1) country and internal and 2) country-only versions.

Land/Ice Mattes
To help with modifying the TruEarth® 1km color base imagery and as textures themselves, the land/ice mattes separate land and ice from ocean. One land/ice matte is land plus polar ice masses in white and ocean in black; the second land/ice matte includes lakes and waterways in black along with the ocean. The matte images can also be used as displacement maps to create simple globe models with elevated land/ice masses.

Land-only Mattes
Like the land/ice mattes, the land-only mattes can be used to modify color base imagery or as textures themselves. The only difference is that polar ice masses are not portrayed. Land appears in white and ocean in black; the second matte includes lakes and waterways in black along with the ocean.

TruEarth® 1km SPECIFICATIONS AND TILE FORMAT.

TruEarth® 1km Specifications:

TruEarth® 1km imagery is provided in the industry-standard .TGA file format.

TruEarth® 1km Tile Format:

1km TruEarth®: 8 tiles x 4 tiles; each tile 5,400 x 5,400 pixels
Total size = 43,200 x 21,600 pixels

TruEarth® 1km PRICING.
The TruEarth® 1km imagery collection is available off the shelf with delivery on DVD media.