Topography
It's topo-licious!
Oddly, there is a plethora of topographical information available on the Internet. And coincidentally, making real and fictitious computer-generated landscapes is also quite easy. This page will serve as a gallery of images, a tutorial, and an index to resources.

Gallery
Click on the small images to see a larger version.
New images are added to the top.

Marsface Mars Face The real face on Mars.
Sunrays 1 Sunrays I Another ocean view, now with volumetric lighting so the beams of light can be seen going through the atmosphere. Compare with Sky & Water below.
Mountain 3 Mountain III A generic mountain view.
Mountain 2 Mountain II Yet another lovely mountain vista.
Canyon I Canyon I Fairy unrealistic water...
River I River I Another one of my first images made with Terragen 0.7 (reflective water). One of my favorites - a realistic river with muddy water.
Water Sunset Sky & Water A Terragen-rendered image. Basically, it's the sky... and a sunset... and the ocean.
Steptoe Butte Steptoe A geological feature in eastern Washington state. The color's a bit off and the vertical scale isn't exact, but other than that...
Sunset Sunset A generic Terragen image.
Pyramids Pyramids The height field was created for the pyramids by using a rectangular gradient fill pattern in Paint Shop Pro and pasting differently-sized copies of the fill pattern in different places across the map. This creates three-dimensional pyramid shapes.
Temple Temple This was created similarly to the method for the pyramids, using a gradient pattern. But, after the pattern was in place, I used non-standard color reduction to reduce the image to 30 colors, which had the effect of turning what would normally be a smooth pyramid into a stepped pyramid. It can hardly be seen, but the steps are covered in green on top while the sides are rock-colored.
Two Worlds Two Worlds Terragen and Raytracing come together. The mountains in the foreground are a Terragen-generated image which I used as an image map (with the sky part transparent) and stuck in a raytraced scene with the galaxy and stars in the background.
Real/Fake Helen Mt. St. Helen's An actual satellite view of Mt. St. Helen's (top) and an image created from digital data (bottom).
Mt. St. Helen's Mt. St. Helen's Created with data from the USGS and the program Terragen. Since Terragen can only import raw 8-bit graphical data*, I converted the DEM information to a Targa, which I resized to 257x257 resolution in Paint Shop Pro. Then I saved it as an 8-bit greyscale RAW file and imported it into Terragen where I added the texture and 3-D clouds.

* Or there are programs listed below to import and export in Terragen's TER format.
Mt. St. Helen's...Before Mt. St. Helen's Before Image The mountain on the morning before its Big Day? The USGS has data from before and after.
Fake Terrain Fake Terrain The first image I ever created in Terragen, using random terrain.
Dawn Dawn Morning scene of a fictitious mountain created in Terragen. I increased the contrast in Paint Shop since I couldn't get the sun bright enough using Terragen.
Spokane Spokane I can't remember what data I used for this, but I think it's from around Spokane (eastern Washington state). Kashmir has two rendering modes: Z-buffer and raytrace. This shows Kashmir's raytraced and perfectly reflective water. As usual, Kashmir's ground textures are very unrealistic since it simply maps a texture onto the heightfield.
Generic Mountain Generic Mountain A generic mountain with interesting clouds. Actually taken from USGS data for Steptoe Butte (see above), but the vertical scale was stretched and a different texture was used for the mountain.
Near Asotin Asotin, Washington Comparison of an image created electronically (using DLGv32) and an actual aerial photograph. The Snake River is the vertical waterway on the east side; the horizontal branch at the top of the image is Asotin Creek. The sleepy villa of Asotin exists in the area where the two waterways connect at the top of the image; about 32 miles south of Pullman. Clarkston is just out of range north of this map. The area of this is about 18 miles wide by 20 miles high. The original aerial photograph was very dark grey, so I increased the brightness, contrast, and added some color. Took a bit of time trying to figure out how these maps are related since the digital data covers an enormous area and I wasn't even sure the picture I had showed anything relating to the data or even if they both were at the same scale.
Information
Also see the Programs and Data sections.

Bitmap
A file containing a rectangular array of color values, as opposed to other formats that might store line-based information. I don't believe formats like JPG are considered bitmapped since they actually lose image information during compression and there is no certain color for any single point, whereas formats like GIF, though they compress, don't lose information in the process and store every pixel as a certain color. Other commonly used bitmap formats are Targa (TGA) and Windows bitmap (BMP). Bitmapped images are usually used for heightfields.
DEM
Digital Elevation Map. A file which contains topographical information over a set area. Information is usually stored as a text file and typically contains such information as the geographical location of the four corners of the data, the values of the highest and lowest points, and which units are used in the DEM to measure these (typically arc-seconds and meters). The data consists of an array of numbers telling the height at each point over the whole area.
DRG
Digital Raster Graphic. A digital image (not vector or topographical data), usually mapped to the coordinates on the globe where it appears. Often similar in appearance to a regular "roadmap." May have names of locations, roads, rivers, and topographical features written directly on it along with contour lines.
GIF
Graphics Interchange Format. Used for web graphics but rarely for heightfields since, though GIF files have relatively good compression, they only allow up to 256 colors and are more difficult to read.
Heightfield
Grand Canyon WestA two-dimensional representation of a three-dimensional object. The image to the right is a heightfield image converted from a USGS DEM file of the western Grand Canyon. The "Topography" image at the top of this page was made with a simple heightfield. Usually the brighter color values correspond to higher land areas, but programs such as POV-Ray also accept specially-encoded 16-bit bitmapped files which look like noise when viewed. (16-bit means more values can be used for a single point - up to 65,536 whereas 8-bit only allows 256.)
SDTS
Spatial Data Transfer Standard. A standard for encoding spacial information for use across various computer platforms. It includes the ability to encode DEM-type data, line-based data (for boundaries, transportation, and hydrography among others), and various points of interest (cities, counties, etc). For creating graphical renderings it's not as useful as the DEM format since the height data isn't as readily converted to other formats, but there are programs listed below to do just this. SDTS information usually comes in packets of multiple files with the extension DDF and a catalog directory file ending in CATD.DDF. One of its uses is overlaying hydrographic or transportation data over a DEM file to see how roads and waterways are related to the actual geography of the land. (DLGv32 is excellent for this.)
Targa
A bitmapped file format, usually with a TGA extension. Very commonly used.

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This page created and maintained by Sean O'Malley.