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Colwell, R. N.

Publications and source records attributed to Colwell, R. N..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Optical vs. electronic enhancement of remote sensing imagery

Basic aspects of remote sensing are considered and a description is provided of the methods which are employed in connection with the optical or electronic enhancement of remote sensing imagery. The advantages and limitations of various image enhancement methods and techniques are evaluated. It is pointed out that optical enhancement methods and techniques are currently superior to electronic ones with respect to spatial resolution and equipment cost considerations. Advantages of electronic procedures, on the other hand, are related to a greater flexibility regarding the presentation of the information as an aid for the interpretation by the image analyst.

Colwell, R. N.↗
NASA NTRS1975

Usefulness of LANDSAT data for monitoring plant development and range conditions in California's annual grassland

A network of sampling sites throughout the annual grassland region of California was established to correlate plant growth stages and forage production to climatic and other environmental factors. Plant growth and range conditions were further related to geographic location and seasonal variations. A sequence of LANDSAT data was obtained covering critical periods in the growth cycle. This was analyzed by both photointerpretation and computer aided techniques. Image characteristics and spectral reflectance data were then related to forage production, range condition, range site and changing growth conditions. It was determined that repeat sequences with LANDSAT color composite images do provide a means for monitoring changes in range condition. Spectral radiance data obtained from magnetic tape can be used to determine quantitatively the critical stages in the forage growth cycle. A computer ratioing technique provided a sensitive indicator of changes in growth stages and an indication of the relative differences in forage production between range sites.

Carneggie, D. M.↗
NASA NTRS1975

An integrated study of earth resources in the state of California using remote sensing techniques

The author has identified the following significant results. A weighted stratified double sample design using hardcopy LANDSAT-1 and ground data was utilized in developmental studies for snow water content estimation. Study results gave a correlation coefficient of 0.80 between LANDSAT sample units estimates of snow water content and ground subsamples. A basin snow water content estimate allowable error was given as 1.00 percent at the 99 percent confidence level with the same budget level utilized in conventional snow surveys. Several evapotranspiration estimation models were selected for efficient application at each level of data to be sampled. An area estimation procedure for impervious surface types of differing impermeability adjacent to stream channels was developed. This technique employs a double sample of 1:125,000 color infrared hightflight transparency data with ground or large scale photography.

Colwell, R. N.↗
NASA NTRS1975

California resource inventory via satellite sensing

There is a rapidly increasing need for wise management of such earth resources as agricultural crops, timber, forage, water, minerals, soils, fish, wildlife and oceanographic and atmospheric resources. An important first step leading to such management is that of obtaining accurate inventories of these resources, quickly, economically, and at suitably frequent intervals. Remote sensing from such manned satellites as Skylab, and from such unmanned satellites as those in the Landsat series, is proving to be of great value in the making of these inventories. Numerous examples are given of the uses made of satellite sensing as an aid to resource inventory in California. Also included is a consideration of the optimum uses that can be made of Skylab-EREP type data in conjunction with lower and higher resolution remote sensing data as acquired by Landsat-type vehicles and by aircraft, respectively.

Colwell, R. N.↗
NASA NTRS1974

An integrated study of earth resources in the state of California using remote sensing techniques

Progress and results of an integrated study of California's water resources are discussed. The investigation concerns itself primarily with the usefulness of remote sensing of relation to two categories of problems: (1) water supply; and (2) water demand. Also considered are its applicability to forest management and timber inventory. The cost effectiveness and utility of remote sensors such as the Earth Resources Technology Satellite for water and timber management are presented.

Colwell, R. N.↗
NASA NTRS1974

Introduction

There are no author-identified significant results in this report.

Colwell, R. N.↗
NASA NTRS1974

Water supply studies

There are no author-identified significant results in this report.

Colwell, R. N.↗