Search for catalog records

•  

  USGS_Eco_2_SurfForm - Land Surface Forms

  

   

  The U.S. Geological Survey (USGS) has generated land surface form classes for the contiguous United States. These land surface form classes were created as part of an effort to map standardized, terrestrial ecosystems for the nation using a classification developed by NatureServe (Comer and others, 2003). Ecosystem distributions were modeled using a biophysical stratification approach developed for South America (Sayre and others, 2008) and now being implemented globally (Sayre and others, 2007). Land surface forms strongly influence the differentiation and distribution of terrestrial ecosystems, and are one of the key input layers in the ecosystem delineation process. The methodology used to produce these land surface form classes was developed by the Missouri Resource Assessment Partnership (MoRAP). MoRAP made modifications to Hammond's (1964a, 1964b) land surface form classification, which allowed the use of 30-meter source data and a 1 km2 window for neighborhood analysis (True 2002, True and others, 2000). While Hammond's methodology was based on three variables, slope, local relief, and profile type, MoRAP's methodology uses only slope and local relief (True 2002). Slope is classified as gently sloping or not gently sloping using a slope threshold of 8%, local relief is classified into five classes (0-15m, 15-30m, 30-90m, 90-150m, and >150m), and eight landform classes (flat plains, smooth plains, irregular plains, escarpments, low hills, hills, breaks, and low mountains) were derived by combining slope class and local relief. The USGS implementation of the MoRAP methodology was executed using the USGS 30-meter National Elevation Dataset (NED) and an existing USGS slope dataset. In this implementation, a new land surface form class, the high mountains/deep canyons class, was identified by using an additional local relief class (> 400m). The drainage channels class was derived independently from the other land surface form classes. This class was derived using two of Andrew Weiss's slope position classes, "valley" and "lower slope" (Weiss 2001, Jenness 2006). The USGS implemented Weiss's algorithm using the 30-meter NED and a 1 km2 neighborhood analysis window. The resultant drainage channel class was combined into the final land surface forms dataset.

•  

  Natural Earth Rivers, Lake Centerlines (scale ranks + tapering) 1:50m

  

   

  Shapefile created using generalized single-line drainages including optional lake centerlines data from the 10 million rivers. The 50 million rivers primarily derive from World Data Bank 2. Double line rivers in WDB2 were digitized to created single line drainages. All rivers received manual smoothing and position adjustments to fit shaded relief generated from SRTM Plus elevation data, which is more recent and (presumably) more accurate. Lake centerlines obtained by manually drawing connecting segments in reservoirs. When available, Admin 0 and 1 political boundaries in reservoirs serve as the lake centerlines. Ranked by relative importance. Includes name and line width attributes for creating tapered drainages.

•  

  USGS - eco_4_Ecosystems - Terrestrial Ecosystems

  

   

  The U.S. Geological Survey (USGS) modeled the distribution of terrestrial ecosystems for the contiguous United States using a standardized, deductive approach to associate unique physical environments with ecological systems characterized in NatureServe's Ecological Systems of the United States classification (Comer et al., 2003). This approach was first developed for South America (Sayre et al., 2008) and is now being implemented globally (Sayre et al., 2007). Unique physical environments were delineated from a massive biophysical stratification of the nation into the major structural components of ecosystems: biogeographic regions (Cress et al., 2008c), land surface forms (Cress et al., 2008a), surficial lithology (Cress et al., 2008d), and topographic moisture potential (Cress et al., 2008b). Each of these structural components was mapped for the contiguous United States and then spatially combined to produce ecosystem structural footprints which represented unique abiotic (physical) environments. Among 49,168 unique structural footprint classes, 13,482 classes which met a minimum pixel count threshold (20,000 pixels) were aggregated into 432 NatureServe ecosystems through semi-automated labeling process using rule set formulations for attribution of each ecosystem.

•  

  Natural Earth, Rivers, Lake Centerlines (scale ranks + tapering) 1:10m

  

   

  Single-line drainages including optional lake centerlines and supplementary data for North America and Europe. Shapefile created using rivers data that primarily derive from World Data Bank 2. Double line rivers in WDB2 were digitized to created single line drainages. All rivers received manual smoothing and position adjustments to fit shaded relief generated from SRTM Plus elevation data, which is more recent and (presumably) more accurate. Lake centerlines obtained by manually drawing connecting segments in reservoirs. When available, Admin 0 and 1 political boundaries in reservoirs serve as the lake centerlines. Ranked by relative importance. Includes name and line width attributes for creating tapered drainages.

•  

  Natural Earth I with Shaded Relief, Water, and Drainages 1:10m

  

   

  Shapefile created using satellite-derived land cover data and shaded relief presented with a light, natural palette suitable for making thematic and reference maps. Go to this website for more information on Natural Earth 1. Two sizes are offered: large size at 21,600 x 10,800 pixels and medium at 16,200 x 8,100. Coloring based on land cover.

•  

  Natural Earth, Gray Earth with Shaded Relief, Hypsography, and Flat Water 1:10m

  

   

  Shapefile created using relief shading and hypsography derived from modified SRTM Plus elevation data at 1km resolution. Modifications include patching the eastern Himalayas and southern Andes with better elevation data from Viewfinder Panoramas. Daniel Huffman, University of Wisconsin, Madison, created the regionally equalized hypsography that forms the foundation of Gray Earth. Two sizes are offered: large size at 21,600 x 10,800 pixels and medium at 16,200 x 8,100. The aim of Gray Earth is mapmakers working in black and white and those seeking a neutral terrain base map on which to overlay vibrant colors representing thematic data. Against the gray terrain, colors will pop. The terrain combines shaded relief and hypsography in even proportions and with just the right amount of contrast; Earth’s landforms are clear to see yet the terrain is light enough so as not to interfere with overprinting type and lines. Gray Earth is also highly malleable in Photoshop. A simple levels adjustment can make the terrain lighter or darker depending on your map design intent.

•  

  USGS_Eco_1_SurfLitho - Surficial Lithology

  

   

  The U.S. Geological Survey (USGS) has generated a new classification and map of the lithology of surficial materials for the contiguous United States. This was developed as part of an effort to map standardized, terrestrial ecosystem distributions for the nation using a classification developed by NatureServe (Comer and others, 2003). This ecosystem mapping methodology, which delineates ecosystems by mapping and integrating their major structural components, was first developed for South America (Sayre and others, 2008) and is now being implemented globally (Sayre and others, 2007). Surficial lithology strongly influences the differentiation and distribution of terrestrial ecosystems, and is one of the key input layers in the ecosystem delineation process. These surficial lithology classes were derived from the USGS map "Surficial Materials in the Conterminous United States", which was based on texture, internal structure, thickness and environment of deposition or formation of materials (Soller and Reheis, 2004). This original map was produced from a compilation of regional surficial and bedrock geology source maps using broadly defined common map units for the purpose of providing an overview of the existing data and knowledge (Soller and Reheis 2004). For the national terrestrial ecosystem mapping effort, the original 28 lithology classes were reclassified into a set of 18 lithologies that typically control or influence the distribution of vegetation types (Kruckeberg, 2002).

•  

  Natural Earth Lakes + Reservoirs - Natural and Artificial Lakes 1:50m

  

   

  Shapefile created using generalized data from 10 million lakes theme. The 10 million lakes primarily derive from World Data Bank 2 with numerous reservoir additions from imagery sources. Diminishing areal extent of Aral Sea and Lake Chad was digitized from recent satellite imagery. Ranked by relative importance, coordinating with river ranking. Includes name attributes.

•  

  USGS - ecosys_US (MapServer) (parent)

   

  This map presents the terrestrial ecosystems in the conterminous United States, and was developed as part of the United States Geological Survey’s (USGS) effort to model the distribution of terrestrial ecosystems using the geospatial mapping methodology that was developed from a deductive, biophysical stratification approach to delineate ecosystems by their major structural elements (Sayre and others, 2009). Each major structural component of ecosystems (land surface forms, surficial lithology, bioclimates, topographic moisture potential, and so forth) was modeled and then spatially combined to produce a new map of biophysical settings, termed ecosystem structural footprints. These ecosystem structure units characterize the abiotic (physical) potential of the environment. As the final step in this process, the unique structural footprints are aggregated into the terrestrial ecosystems classification that was developed by NatureServe (Comer and others, 2003). Additional information and access to this data is available at http://rmgsc.cr.usgs.gov/ecosystems/.

•  

  Natural Earth I with Shaded Relief and Water 1:50m

  

   

  Shapefile created using satellite-derived land cover data and shaded relief presented with a light, natural palette suitable for making thematic and reference maps. Natural Earth I is available with ocean bottom data, or without. File size: 10,800 x 5,400 pixels. Coloring based on land cover.