About the Color Landform Atlas of the United States

About the Color Landform Atlas of the United States
This is version 2 of the Color Landform Atlas of the United States. It has less glitz ( see one of the old state pages) but more content. Each state link brings up a menu of links to maps and other online information about the state. There are two main types of links on each state page: maps and images local to this site, and links to external web sites. The external links may break from time to time but will be fixed where possible.

A couple important notes

The shaded relief maps are not satellite images.
They are created from arrays of elevation data. The elevation data was derived from contour maps elsewhere, some is available from the USGS. Actual satellite images are also available on this site.
If you want to use the maps check the section below titled Using these maps for your project.

What's New in version 2
New in version 2 of this page are:

Satellite images. These show landforms and vegetation patterns for each state. I have been collecting them since late 1995 from data acquired directly from the satellites by our ground station.
1895 state maps. I scanned these in from an old Rand McNally Atlas of the World. They are very detailed, almost hard to read. Railroads were a dominant means of transportation, they are shown on the maps instead of roads.
PostScript map. These are intended to be download and printed on a PostScript printer. If your web browser calls up a PostScript viewer the map may be displayed upside down, most viewers have an option to rotate the displayed page.
Black and white map. These are useful where black and white is needed.
Many new external links. A number of external pages that are organized by state have been included. Perhaps the most fun link is Roadside America (check it for Rhode Island, down under Other Attractions: Man-eating tree root)
Other items are in the works for these pages.

The maps
Currently the following maps are available for each state (with a few exceptions).

A topographic map optimized to show the landforms. The same color shading is used across the country.
A map showing counties in a state. The background topography has been somewhat suppressed to allow the county boundaries to show well.
A black and white version of the shaded relief map. If black and white is needed these maps work better than converting the color ones. They are not completely black and white but close enough to modify easily.
Satellite images of the state. These have been obtained here directly from the NOAA weather satellites and use the AVHRR image data.
An 1895 map of each state. These are from an old Rand McNally Atlas of the World. The 1895 map of Delaware is included on the 1895 Maryland map.
A PostScript map of counties in the state. These are intended for download and printing on a PostScript printer.
The first two maps all have the same maximum image length (900 pixels) so the actually scale varies from state to state. Long narrow states also have more detailed subsections available. More maps will be added later.
The elevation key is intended for the topographic maps. The county maps use the same colors but with less contrast. It may be convenient to start another browser window and view the elevation key image at the same time as the map of interest.
The same data and coloring is used for the state maps as for the previous JHU/APL Digital Relief Map of the U.S. which covers the U.S. at a uniform scale in 60 GIF images.
Even though the same color scheme is used as for earlier maps a new coloring algorithm is in use. The coloring for some maps is improved, for others it is not as good. The old coloring algorithm used a median cut technique which did not handle small areas of elevation extremes well. An example problem area is Mt. Washington in New Hampshire, it was miscolored on the previous maps. The new algorithm does a better overall job but has occasional problems along the coast.
The Shaded Relief Maps

The data
The elevation data has a horizontal resolution of 1/2 arc minute for both East/West and North/South, and a vertical resolution of 20 feet.
The data has some artifacts which are visible in the maps. One type of artifact is a minor ridge along seams of the original data. A few wild points cause extraneous high or low points. Vertical striations are also visible in a few places where no such feature should exist. The artifacts are not serious for the main purpose of these maps which is to show landforms.
Map projection and shading
The map projection is the simplest possible one, Cylindrical Equidistant. The shape is corrected for the latitude indicated. This is not the best projection as far as distortion goes but it has the big advantage of making it easy to write applications that can plot objects given their coordinates or read coordinates from the image.
Information on converting between image coordinates and latitude/longitude has been embedded in each image (as of about 1995 Jan 30 23:00 UT). This information is in the first 88 bytes of the bottom line of each image. If these bytes are displayed as ascii text they will appear as something like the following example:
1234567890 80 870 80 465 -89.7000 -81.9000 36.3000 39.3000
which happens to be for Kentucky. The first number is simply a flag to indicate that the scaling info is available in the image. The following numbers are in four pairs:
80 870 is the x range in screen pixels for the map window,
80 465 is the y range in screen pixels for the map window,
-89.7000 -81.9000 is the longitude range of the map, and
36.3000 39.3000 is the latitude range.
This information may be used to overlay additional graphics.
Since this information may be difficult to dig out of the map images it is also made available here (The B&W maps are slightly different scale, here are the coordinates).
The lighting is from the Northwest. Features with slopes toward or away from the lighting direction are shown well. Features with slopes at right angles to this direction may not be shown at their best. The low sun angle is a compromise between showing details in low relief areas and hiding too much in shadowed areas.
Creating the map
The map was created using the IDL programming language running on an HP 735 workstation. IDL includes extensive map projection support, but it was not used for this simple projection.
A web page on making 3-D maps (lost link) by Ryan Foster is available (thanks to David E. Stoner, Abu Dhabi, United Arab Emirates for bringing this to my attention).
The Satellite Images

The data
Data used to make the satellite images were obtained directly from the NOAA weather satellites. These satellites broadcast image data continously. We use a computer board and software from SeaSpace Corporation to capture the data and do some low level processing (such as calibrating and geographically registering images). The IDL programming language was used to do much of the work in generating the final images. More details are available on the list of satellite images for each state.

Using these maps for your project
If you would like to use one or more of these maps or images for a project, please contact Ray Sterner at ray.sterner@jhuapl.edu. Ray is the creator and owner (along with JHUAPL) of these images and maps. JHUAPL has recently licensed this content to North Star Science and Technology, LLC; and commercial user fees for the use and distribution of these maps and images will apply from 1/01/02 forward. User fees will be kept to a minimum, so please contact us with your proposed uses of this content. Permission will likely be granted, and user fees will be small. Some educational uses may receive a waiver of all user fees. But please send us information regarding the use you have in mind for this content, its likely distribution, and the nature of your host organization. Applications that would reflect poorly on the JHUAPL will not be allowed. Any use of this content must include the copyright and credit JHUAPL and Ray Sterner. In addition, any use of this content must reference or link back to this web page at http://fermi.jhuapl.edu/states/.