Color Conterminous United States Shaded Relief 200-Meter Resolution
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Frequently-anticipated questions:
- What does this data set describe?
- How should this data set be cited?
- What geographic area does the data set cover?
- What does it look like?
- Does the data set describe conditions during a particular time period?
- What is the general form of this data set?
- How does the data set represent geographic features?
- How does the data set describe geographic features?
- Who produced the data set?
- Why was the data set created?
- How was the data set created?
- How reliable are the data; what problems remain in the data set?
- How can someone get a copy of the data set?
- Who wrote the metadata?
What does this data set describe?
- Title:
- Color Conterminous United States Shaded Relief 200-Meter Resolution
- Abstract:
- The color conterminous United States shaded relief data were derived from National Elevation Dataset (NED) data, and show the terrain of the conterminous United States at a resolution of 200 meters. The NED is a raster product assembled by the U.S. Geological Survey, designed to provide national elevation data in a seamless form with a consistent datum, elevation unit, and projection. Data corrections made in the NED assembly process minimize artifacts, permit edge matching, and fill sliver areas of missing data.
- Supplemental_Information:
-
The associated world file is included as part of the GeoTIFF. The
contents of the world file are:
200.0000 0.000000 0.000000 -200.0000 -2262900.0000 1038900.0000
The following projection file can be used when using ESRI's ArcGIS to view the GeoTIFF (any line breaks should be removed): PROJCS["NAD_1983_Lambert_Azimuthal_Equal_Area",GEOGCS ["GCS_Sphere_ARC_INFO",DATUM["D_Sphere_ARC_INFO",SPHEROID ["Sphere_ARC_INFO",6370997.0,0.0]],PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]],PROJECTION ["Lambert_Azimuthal_Equal_Area"],PARAMETER["False_Easting",0.0], PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian", -100.0],PARAMETER["Latitude_Of_Origin",45.0],UNIT["Meter",1.0]]
- How should this data set be cited?
National Atlas of the United States, 200512, Color Conterminous United States Shaded Relief 200-Meter Resolution: National Atlas of the United States, Reston, VA.
Online Links:
- What geographic area does the data set cover?
- West_Bounding_Coordinate: -133
- East_Bounding_Coordinate: -59
- North_Bounding_Coordinate: 51
- South_Bounding_Coordinate: 19
- What does it look like?
- Does the data set describe conditions during a particular time period?
- Calendar_Date: Sep-2002
- Currentness_Reference: Date of elevation data download
- Calendar_Date: Sep-2002
- What is the general form of this data set?
- Geospatial_Data_Presentation_Form: Map
- How does the data set represent geographic features?
- How are geographic features stored in the data set?
This is a Raster data set. It contains the following raster data types:
- Dimensions 17280 x 25740, type Grid Cell
- What coordinate system is used to represent geographic features?
The map projection used is Lambert Azimuthal Equal Area.
- Projection parameters:
-
- Longitude_of_Projection_Center: -100.00
- Latitude_of_Projection_Center: 45.00
- False_Easting: 0.0
- False_Northing: 0.0
Planar coordinates are encoded using Row and column
Abscissae (x-coordinates) are specified to the nearest 200.0
Ordinates (y-coordinates) are specified to the nearest 200.0
Planar coordinates are specified in MetersThe horizontal datum used is None.
The ellipsoid used is Sphere.
The semi-major axis of the ellipsoid used is 6370997.0.
The flattening of the ellipsoid used is 1/1.0.
- How are geographic features stored in the data set?
- How does the data set describe geographic features?
- Shaded relief TIFF image grid cell
- Any of the data elements in the shaded relief file.
(Source: National Atlas of the United States)
- Shaded relief TIFF image values
- Color values for the TIFF image.
(Source: National Atlas of the United States)
Range of values Minimum: 0 Maximum: 255
Who produced the data set?
- Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
- National Atlas of the United States
- Who also contributed to the data set?
- To whom should users address questions about the data?John Hutchinson
SAIC
USGS Center for EROS
Sioux Falls, SD 57198-0001
USA
605-594-6049 (voice)
hutch@usgs.gov
Why was the data set created?
The color shaded relief images were developed to portray the terrain of the United States. They are intended for visual purposes only. The original NED data must be used for conducting analysis and determining elevation values.
How was the data set created?
- From what previous works were the data drawn?
- National Elevation Dataset (source 1 of 4)
-
U.S. Geological Survey, 2002, National Elevation Dataset: U.S. Geological Survey, Sioux Falls, SD.
Online Links:
- Type_of_Source_Media: Online
- Source_Contribution: Elevation information.
- shorelp020l (source 2 of 4)
-
National Atlas of the United States, 1999, Shoreline file in Lambert Azimuthal Equal Area projection: National Atlas of the United States, Reston, VA.
- Type_of_Source_Media: Internal file
- Source_Contribution: Shoreline mask for area of coverage.
- ElevationUS_2002 (source 3 of 4)
-
USGS, Center for EROS, Unpublished material, Conterminous United States Color Elevation Grid.
- Type_of_Source_Media: Internal file
- Source_Contribution: Elevation information.
- GrayscaleUS (source 4 of 4)
-
for, USGS Center EROS, 200509, Grayscale Conterminous United States Shaded Relief 200-Meter Resolution: National Atlas of the United States, Reston, VA.
Online Links:
- Type_of_Source_Media: Online
- Source_Contribution: Elevation information.
- How were the data generated, processed, and modified?
- Date: Dec-2002 (process 1 of 2)
-
Four elevation mosaics were extracted from the National Elevation
Dataset (NED) and used to produce the shaded relief images of the
conterminous United States, Alaska, Hawaii, and Puerto Rico and the U.S.
Virgin Islands. A separate image was created for each of the four
areas because, at 200-meter resolution, file size for an elevation
mosaic of all of the United States would exceed the processing capacity
of some commonly-used GIS and image processing software packages.
For the conterminous United States, elevation data were extracted from the NED and projected to a Lambert Azimuthal Equal-Area (LAZ) projection centered on 100 degrees West, 45 degrees North, with a pixel size of 200 meters. The datum for NED data is NAD83, except for Alaska which uses NAD27. Because there is no ellipsoidal form of the Lambert Azimuthal Equal-Area projection, once data have been projected to LAZ they lose any datum affiliation and instead are based on a sphere with a radius of 6370997 meters. However, some commonly-used software packages will report an error if a datum is not specified, so to accommodate such software, the GeoTIFF for this shaded-relief map layer retains the NAD83 datum associated with the original NED data from which it was derived.
Using the ArcInfo Polygrid command, a 0/1 land/water mask was created for the conterminous United States at the same 200 meter resolution as the elevation data, using coastline data clipped from the National Atlas shoreline file. The land/water mask was applied to the 16-bit elevation grid. The masked elevation grid as well as the mask itself is available on request. More information on the NED may be found by following the links at <http://ned.usgs.gov>.
A color elevation image was created by slicing the elevation data using the ranges (listed in feet; divide by 3.2808 to get meters) and RGB color values below.
From To index red green blue --------------------------------------------------- -250 0 1 220 220 220 1 249 2 127 159 101 250 499 3 130 176 112 500 999 4 160 194 124 1000 1499 5 185 214 124 1500 1999 6 207 224 156 2000 2499 7 223 233 168 2500 2999 8 241 238 166 3000 3499 9 237 223 159 3500 3999 10 240 210 141 4000 4499 11 230 188 138 4500 4999 12 216 165 133 5000 5499 13 197 149 135 5500 5999 14 217 165 156 6000 6499 15 227 183 177 6500 6999 16 223 192 191 7000 7499 17 239 205 217 7500 7999 18 244 215 225 8000 8499 19 243 223 233 8500 8999 20 248 227 232 9000 9499 21 248 233 238 9500 9999 22 246 240 245 10000 19476 23 255 255 255 Water 0 132 193 255
Data sources used in this process:
- National Elevation Dataset
- shorelp020l
Data sources produced in this process:
- ElevationUS_2002
- Date: Aug-2005 (process 2 of 2)
-
ElevationUS_2002 was converted in Adobe Photoshop from RGB to CMY (no
black generated).
The contrast of GrayscaleUS was enhanced in Adobe Photoshop by using a tritone technique. The enhanced grayscale image was added as a black band to the converted color elevation image to create a CMYK color shaded relief image. The CMYK image was converted in Photoshop to RGB for use in the online National Atlas.
In the combined image, the water and non-U.S. land areas no longer had the correct values, so they were reset to meet the requirements of the National Atlas Map Maker. Open water areas were selected using Adobe Photoshops magic wand function and set to a RGB value of (132, 193, 255). The same technique was used to select non-U.S. land, and the RGB value was set to (132, 158, 172).
The Photoshop image was saved in as a TIFF, ingested into ArcInfo as a grid using the command IMAGEGRID, saved as a TIFF from ArcInfo using the command GRIDIMAGE, and then processed through a USGS GeoTIFF software program to create a fully-compliant GeoTIFF with valid header information.
Data sources used in this process:
- ElevationUS_2002
- GrayscaleUS
- What similar or related data should the user be aware of?
National Atlas of the United States, 200512, Color Alaska Shaded Relief 200-Meter Resolution: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200512, Color Hawaii Shaded Relief 200-Meter Resolution: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200512, Color Puerto Rico and the U.S. Virgin Islands Shaded Relief 200- Meter Resolution: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200603, Color Conterminous United States Shaded Relief 200-Meter Resolution, Albers projection: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200603, Color Alaska Shaded Relief 200-Meter Resolution, Albers projection: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200603, Color Hawaii Shaded Relief 200-Meter Resolution, Albers projection: National Atlas of the United States, Reston, VA.
Online Links:
National Atlas of the United States, 200603, Color Puerto Rico and the U.S. Virgin Islands Shaded Relief 200- Meter Resolution, Albers projection: National Atlas of the United States, Reston, VA.
Online Links:
How reliable are the data; what problems remain in the data set?
- How well have the observations been checked?
- How accurate are the geographic locations?
- How accurate are the heights or depths?
- Where are the gaps in the data? What is missing?
Data completeness reflects the content of the original NED elevation data.
- How consistent are the relationships among the observations, including topology?
No tests for logical consistency have been performed on this map layer.
How can someone get a copy of the data set?
Are there legal restrictions on access or use of the data?
- Access_Constraints: None.
- Use_Constraints:
- None. Acknowledgment of the U.S. Geological Survey, Center for EROS and (or) the National Atlas of the United States would be appreciated in products derived from these data.
- Who distributes the data set? (Distributor 1 of 1)Earth Science Information Center, U.S. Geological Survey
507 National Center
Reston, VA 20192
USA
1-888-ASK-USGS (1-888-275-8747) (voice)
- Contact_Instructions:
- In addition to the address above there are other ESIC offices throughout the country. A full list of these offices is at <http://ask.usgs.gov/esic_index.html>.
- What's the catalog number I need to order this data set?
- What legal disclaimers am I supposed to read?
Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the U.S. Geological Survey regarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. Use of trademarks or formats does not constitute endorsement by the U.S. Geological Survey. There are no copyright restrictions on the use, redistribution, or further processing of this map layer. No responsibility is assumed by the U.S. Geological Survey in the use of these data.
- How can I download or order the data?
- Availability in digital form:
Data format: TIFF Network links: <http://nationalatlas.gov/atlasftp.html?openChapters=chpgeol#chpgeol>
- Cost to order the data: There is no charge for the map layer.
- Availability in digital form:
Who wrote the metadata?
- Dates:
- Last modified: 29-Aug-2006
- Metadata author:
-
Peg Rawson
National Atlas of the United States
12201 Sunrise Valley Drive
Reston, VA 20192
USA
703-648-4183 (voice)
atlasmail@usgs.gov
- Metadata standard:
- FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
