John K. Wright

Bio: John K. Wright is an academic researcher. The author has contributed to research in topics: Historical geography & Geographer. The author has an hindex of 13, co-authored 50 publications receiving 7294 citations.

Remote Sensing and Image Interpretation

Abstract: Concepts and Foundations of Remote Sensing Elements of Photographic Systems Basic Principles of Photogrammetry Introduction to Visual Image Interpretation Multispectral, Thermal, and Hyperspectral Sensing Earth Resource Satellites Operating in the Optical Spectrum Digital Image Processing Microwave and Lidar Sensing Appendix A: Radiometric Concepts, Terminology, and Units Appendix B: Remote Sensing Data and Information Resources Appendix C: Sample Coordinate Transformation and Resampling Procedures

A Method of Mapping Densities of Population: With Cape Cod as an Example

Abstract: HE first of the maps presented on page I05 is a conventional population map of Cape Cod in which a symbol for the density covers the whole area of each township. The map is not particularly realistic. Anyone who has visited the region knows that large parts of it are uninhabited. Terminal-moraine ridges run parallel to the north and east shores of the Cape's "upper arm "-to use a term implying comparison of the Cape to an arm shaking its fist at the Atlantic. These moraines are wildernesses of burnt-over land covered with scrub oak and stunted pine. Fringing Nantucket Sound is a string of villages, but elsewhere the sandy outwash plains that intervene between the moraines and the sound are thinly peopled, and one often drives for several miles without seeing a house. At the tip end of the Cape the map shows a density of 200 to 500 to the square mile in the "fist. " As a matter of fact, nearly all the people here live in the compact village of Provincetown along the harbor, and the greater part of the "fist" consists of sand dunes, where the density actually approaches zero. Most of this tract of dunes is maintained by the state as a reservation known as the Province Lands, where the vegetation is carefully fostered in order to prevent the sands from overwhelming the village. Figure I gives no idea whatever of these local differences.

The Open Polar Sea

Abstract: N rOT a speck of ice" was to be seen. "As far as I could discern, the sea was open, a swell coming in from the northward and running crosswise, as if with a small eastern set. The wind was due N.,-enough of it to make white caps,-and the surf broke in on the rocks in regular breakers." The Open Polar Sea! The time was June 24, i854. William Morton, one of the crew of Dr. Elisha Kent Kane's "Second Grinnell Expedition,", stood on the summit of the mighty cliffs along the Greenland northwest coast to which Kane later gave the name "Cape Constitution." The latitude was 800 30' N., farther north than any white man had yet reached in the Western Hemisphere, and the coast line before Morton marked the northernmost known land on the face of the earth. On the other side of Kennedy Channel, Grinnell Land stretched off some 50 miles toward the North Pole. Morton, alas, was mistaken. There is no Open Polar Sea. But during the next 25 years his report and the interpretation Dr. Kane and others put upon it gave a feverish vitality to a dying theory. Belief in open water and a mild clime in "the realm of the Boreal Pole" had persisted for centuries. Inherently it was neither an absurd nor an unimportant theory. Hardheaded seamen and explorers and reputable geographers upheld it, and its record helps explain much that would otherwise be obscure in the history of Arctic discovery. Today it is perhaps of greatest interest as providing an illustration of the nature and growth of scientific error. Since it has been conclusively disproved, we may compare it with the facts and see clearly wherein its proponents went astray.

Vertex component analysis: a fast algorithm to unmix hyperspectral data

Abstract: Given a set of mixed spectral (multispectral or hyperspectral) vectors, linear spectral mixture analysis, or linear unmixing, aims at estimating the number of reference substances, also called endmembers, their spectral signatures, and their abundance fractions. This paper presents a new method for unsupervised endmember extraction from hyperspectral data, termed vertex component analysis (VCA). The algorithm exploits two facts: (1) the endmembers are the vertices of a simplex and (2) the affine transformation of a simplex is also a simplex. In a series of experiments using simulated and real data, the VCA algorithm competes with state-of-the-art methods, with a computational complexity between one and two orders of magnitude lower than the best available method.

Measuring phenological variability from satellite imagery

Abstract: Vegetation phenological phenomena are closely related to seasonal dynamics of the lower atmosphere and are therefore important elements in global models and vegetation monitoring. Normalized difference vegetation index (NDVI) data derived from the National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiom- eter (AVHRR) satellite sensor offer a means of efficiently and objectively evaluating phenological characteristics over large areas. Twelve metrics linked to key phenological events were computed based on time-series NDVI data collected from 1989 to 1992 over the conterminous United States. These measures include the onset of greenness, time of peak NDVI, maximum NDVI, rate of greenup, rate of senescence, and integrated NDVI. Measures of central tendency and variabil- ity of the measures were computed and analyzed for various land cover types. Results from the analysis showed strong coincidence between the satellite-derived metrics and pre- dicted phenological characteristics. In particular, the metrics identified interannual variability of spring wheat in North Dakota, characterized the phenology of four types of grasslands, and established the phenological consistency of deciduous and coniferous forests. These results have implications for large- area land cover mapping and monitoring. The utility of re- motely sensed data as input to vegetation mapping is demon- strated by showing the distinct phenology of several land cover types. More stable information contained in ancillary data should be incorporated into the mapping process, particu- larly in areas with high phenological variability. In a regional or global monitoring system, an increase in variability in a region may serve as a signal to perform more detailed land cover analysis with higher resolution imagery.

Physical Place and Cyberplace: The Rise of Personalized Networking

Abstract: Computer networks are social networks. Social affordances of computer-supported social networks – broader bandwidth, wireless portability, globalized connectivity, personalization – are fostering the movement from door-to-door and place-to-place communities to person-to-person and role-to-role communities. People connect in social networks rather than in communal groups. In-person and computer-mediated communication are integrated in communities characterized by personalized networking. Les reseaux informatiques sont des reseaux sociaux. Les possibilites sociales qu’offrent les reseaux sociaux informatises – bande passante plus large, portabilite sans fil, connectivite mondiale, personnalisation – sont en train de favoriser le passage de communautes de porte-a-porte et de lieu-a-lieu vers des communautes d’individu-a-individu et de role-a-role. Ainsi, les gens se lient davantage dans des reseaux sociaux que dans des collectivites. Les communications directes et via l’informatique sont integrees dans des communautes caracterisees par un maillage personnalise.