Modeling global Hammond landform regions from 250‐m elevation data

Abstract

In 1964, E.H. Hammond proposed criteria for classifying and mapping physiographic regions of the United States. Hammond produced a map entitled "Classes of Land Surface Form in the Forty-Eight States,USA", which is regarded as a pioneering and rigorous treatment of regional physiography. Several researchers automated Hammond's model in GIS. However, these were local or regional in application, and resulted in inadequate characterization of tablelands. We used a global 250 m DEM to produce a new characterization of global Hammond landform regions. The improved algorithm we developed for the regional landform modeling: (1) incorporated a profile parameter for the delineation of tablelands; (2) accommodated negative elevation data values; (3) allowed neighborhood analysis window (NAW) size to vary between parameters; (4) more accurately bounded plains regions; and (5) mapped landform regions as opposed to discrete landform features. The new global Hammond landform regions product builds on an existing global Hammond landform featuresproduct developed by the U.S. Geological Survey, which, while globally comprehensive, did not include tablelands, used a fixed NAW size, and essentially classified pixels rather than regions. Our algorithm also permits the disaggregation of "mixed" Hammond types (e.g. plains with high mountains) into their component parts.

Mapping mountain areas: learning from Global, European and Norwegian perspectives

“…The second approach has been to consider mountains as one of a number of categories that, together, characterise either the entire landmass of the world, or parts of it, in terms of landforms, both globally (Sayre et al 2014;Karagulle et al 2017) and, for example, in China (e.g., Cheng et al 2011Cheng et al , 2017Tang 2017) or biogeographic, environmental or landscape zones (e.g., EEA 2018; Metzger et al 2005;Puschmann 2005). Some of these delineations have been used as the basis for further research.…”

“…In addition to these two maps which focus only on mountains, two recent global maps identify mountains as specific landforms (Sayre et al 2014;Karagulle et al 2017). The former map, commissioned by the inter-governmental Group on Earth Observations (GEO), is at a spatial resolution of 250 m: pixels with a slope of >8% and relative relief of 91-400 m are identified as low mountains, and those with a relative relief >400 m as high mountains.…”

“…The four layers are overlain to create of ecological land units (ELUs) with many anticipated uses, such as the assessment of ecosystem services and of climate change and its impacts, and setting priorities for biodiversity conservation. The map developed by Karagulle et al (2017) also has a spatial resolution of 250m, and identifies four mountain classes: low mountains; scattered low mountains; high mountains; and scattered high mountains. Together, the former two classes cover 27 percent of the Earth's land surface; the two latter cover 9 percent.…”

“…The 'Global Mountain Explorer' website (https://rmgsc.cr.usgs. gov/gme) now allows comparison of three of these: Kapos et al (2000), Körner et al (2016), and Karagulle et al (2017). One of these delineations was produced incidentally; the others were developed primarily for ecological purposes.…”

A new 30 meter resolution global shoreline vector and associated global islands database for the development of standardized ecological coastal units

“…Alternatively, the use of a geomorphic feature, such as the limit of a global coastal plains landform produced from terrain characteristics, will also be evaluated for use. A terrain-based global landforms layer (Karagulle et al 2017) derived from a 250 m digital elevation model (Danielson and Gesch 2011) identifies 16 classes of landforms (four mountain classes, four tablelands classes, four hills classes, and four plains classes). This global landforms layer could be used to produce a global coastal plains layer, which would represent the occurrence of coastal plains features that intersect with the GSV and are bounded inland by hills and mountains.…”