Engineering topics

Poonai, P.

Publications and source records attributed to Poonai, P..

6 records

NASA NTRS1977

Generalized vegetation map of north Merrit Island based on a simplified multispectral analysis

A simplified system for classification of multispectral data was used for making a generalized map of ground features of North Merritt Island. Subclassification of vegetation within broad categories yielded promising results which led to a completely automatic method and to the production of satisfactory detailed maps. Changes in an area north of Happy Hammocks are evidently related to water relations of the soil and are not associated with the last winter freeze-damage which affected mainly the mangrove species, likely to reestablish themselves by natural processes. A supplementary investigation involving reflectance studies in the laboratory has shown that the reflectance by detached citrus leaves, of wavelengths lying between 400 microns and 700 microns, showed some variation over a period of seven days during which the leaves were kept in a laboratory atmosphere.

Poonai, P.↗

NASA NTRS1975

Environmental monitoring of North Merritt Island

The environmental impact of the space shuttle operation on North Merritt Island was studied mainly by means of color infrared photos and field visits. An attempt was also made to generate character maps of the Island using LANDSAT data with a view to decreasing the cost of monitoring and making the process more flexible in terms of rapid estimation of the extent of selected ground features. It seems possible that the IMAGE-100 output can be improved by using it in conjunction with software systems which are used for generating character maps. All the methods for generating maps show six main plant associations on North Merritt Island. It was shown that the six associations are related by ecological succession, merge into their neighbors in terms of component species and can be observed for changes in terms of component species.

Poonai, P.↗

NASA NTRS1975

Remote sensing over North Merritt Island

The author has identified the following significant results. For monitoring the surface environment of North Merritt Island, two methods are studied, namely, color infrared photography and machine processing of LANDSAT multispectral scanner data. C.I.R. photos made at a height of about 12,000 ft were found to define the borders of ground features around the space shuttle runway with a nonsignificant mean error of 0.138 meters but a wide range, which can be reduced with photos taken at about 6,000 ft. LANDSAT multispectral scanner data, transformed by use of the function f(g) = g1 + g2 -g3 -g4 where g1, g2, g3, and g4 represent reflectance or grey levels of multispectral channels 1,2,3, and 4, gave values which are classifiable into a relatively small number of categories.

Poonai, P.↗

NASA NTRS1974

A study of lagoonal and estuarine processes and artificial habitats in the area of the John F. Kennedy Space Center

In order to study the influence of an artificial habitat of discarded automobile tires upon the biomass in and around it, three sites were selected in the Banana River, one of which will serve as a control and the other two as locations for small tire reefs. Measurements and correlation studies of the biomasses and the species indicate that the biodynamics of the sites are appreciably the same in the three cases, that there are probably adequate populations at the lower trophic levels, that there are perhaps reduced numbers of upper level carnivores, and that it is likely that small artificial havens can contribute to an increase in populations of certain species of gamefish.

Poonai, P.↗

NASA NTRS1974

Remote sensing by ERTS satellite of vegetational resources believed to be under possible threat of environmental stress

The distribution of natural vegetation types on North Merritt Island, Florida, was studied by analysis of ERTS multispectral scanner data on the image-100 computer system. The boundaries of six distinct plant associations were located on photos made on the image analyzer, with an insignificant mean error of -24.38 meters. The six plant associations are described; each had a characteristic spectral signature. The difference in average reflectance grey level between the lowest of the four spectral scanning bands and the highest spectral scanning band for the six vegetation types was determined. The decreasing trend of the differences is strongly negatively correlated with height of land.

Poonai, P.↗

NASA NTRS1973

Evaluation of an artificial estuarine habitat-initial stage

In order to study the influence of an artificial habitat of discarded automobile tires upon the biomass in and around it, three sites were selected in the Banana River of which two will contain small groups of tires and one will not. Over a given period, the populations in and around the tires will be compared with those which existed initially or prevail on the natural site. Preliminary observations indicate that adequate numbers may be present in the lower trophic levels but that there are perhaps inadequate populations of upper level carnivores which it appears can be increased by an artificial habitat.

Poonai, P.↗