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At least 397 records · Page 22

Planetary Nebulae with Supporting IR Data

We present new HST/WFPC2 imagery for the planetary nebula (PN) NGC 6818. Observations were made in line filters F437N, F487N, F502N, and F656N plus continuum filter F547M. The primary goal was to develop a high spatial resolution (approx. 0.1 in.) map of the intrinsic line ratio [O III] 4363/5007 and thereby evaluate the electron temperature (T(sub e)) and the mean-square T(sub e) variation (t(sup 2) across the PN. In this process we developed an extinction map from the F487N (H(beta)) and F656N (H(alpha)) images by comparing the observed line ratios in each pixel to the theoretical ratio and computing a c(H(beta)) map which was used to correct the observed 4363/5007 ratios for reddening. We also adjust for the continuum contribution to the line filter data. We present color-coded pictures of the reddening (c(H(beta))) map, the [O III] T(sub e) map, as well as our determinations of t(sup 2). The T(sub e) map shows a decline from approx. 14000 K in the inner regions to approx. 11000 K at the outer edge. Such a radial T(sub e) gradient is expected for a high-excitation nebula with a prominent He(++) zone such as NGC 6818. A composite of images taken in 3 filters (F656N, red; F487N, blue; and F502N, [O III] 5007, green) shows a roughly spherical outer envelope as well as a brighter vase-shaped interior "bubble". There is a prominent orifice to the North and a smaller one to the South, along the major axis, possibly caused by a blow-out from a fast wind. This nebula has an appearance remarkably similar to that of the PN NGC 3918 previously imaged with HST by H. Bond. We note from the continuum images (F547M) two stars in the nebular field that are fainter than the prominent central star; these are roughly 2-4 sec. N and NE of the central star. Further study is needed to establish whether or not there may be a physical association of either star with the central star.

Harrington, J. Patrick↗

Image Analysis for Facility Siting: a Comparison of Lowand High-altitude Image Interpretability for Land Use/land Cover Mapping

For two test sites in Pennsylvania the interpretability of commercially acquired low-altitude and existing high-altitude aerial photography are documented in terms of time, costs, and accuracy for Anderson Level II land use/land cover mapping. Information extracted from the imagery is to be used in the evaluation process for siting energy facilities. Land use/land cover maps were drawn at 1:24,000 scale using commercially flown color infrared photography obtained from the United States Geological Surveys' EROS Data Center. Detailed accuracy assessment of the maps generated by manual image analysis was accomplished employing a stratified unaligned adequate class representation. Both 'area-weighted' and 'by-class' accuracies were documented and field-verified. A discrepancy map was also drawn to illustrate differences in classifications between the two map scales. Results show that the 1:24,000 scale map set was more accurate (99% to 94% area-weighted) than the 1:62,500 scale set, especially when sampled by class (96% to 66%). The 1:24,000 scale maps were also more time-consuming and costly to produce, due mainly to higher image acquisition costs.

Borella, H. M.↗

Geologic and mineral and water resources investigations in western Colorado, using Skylab EREP data

The author has identified the following significant results. Discovery of three major north-trending, throughgoing faults in the Front Range, previously mapped only as isolated segments, demonstrates the utility of space photography and may lead to reinterpretation of the Front Range tectonic style. Faulting and alteration appear to be the most useful indicators of mineralization in central Colorado. These phenomena appear on Skylab photography as tonal lineaments and color anomalies. Twenty-three lineaments have been mapped in the San Juan Mountains, the longest of which is 156 km long. Twelve lineaments intersect or are tangent to calderas. Intrusive domes are aligned along lineaments, but calderas appear to occur at the intersections of major lineaments. Lineaments can be recognized on some EREP passes but not on other passes over the same area. The difference is attributed to solar elevation effects. Bedding attitudes can be photogeologically estimated down to surprisingly low dips, on the order of + or - 1-2 deg, and attitudes can be subdivided easily into quantitative groups. The primary application of Skylab photography to geologic mapping in montane areas is clearly limited to regional mapping at scales smaller than 1:24,000.

Lee, K.↗

An evaluation of satellite data for estimating the area of small forestland in the southern lower peninsula of Michigan

A winter black and white band 5, a winter color, a fall color, and a diazo color composite of the fall scene were used to assess the use and potential of LANDSAT images for mapping and estimating acreage of small scattered forest tracts in Barry County, Michigan. Forests as small as 2.5 acres were mapped from each LANDSAT data source. The maps for each image were compared with an available forest-type map. Mapping errors detected were categorized as boundary and identification errors. The most frequently misclassified areas were agriculture lands, treed-bogs, brushlands and lowland and mixed hardwood stands. Stocking level affected interpretation more than stand size. The overall level of the interpretation performance was expressed through the estimation of classification, interpretation, and mapping accuracies. These accuracies ranged from 74 between 74% and 98%. Considering errors, accuracy, and cost, winter color imagery is the best LANDSAT alternative for mapping small forest tracts. However, since the availability of cloud-free winter images of the study area is significantly lower than images for other seasons, a diazo enhanced image of a fall scene is recommended as the best next best alternative.

Karteris, M. A.↗

Lunar magnetic anomalies detected by the Apollo subsatellite magnetometers

Properties of lunar crustal magnetization thus far deduced from Apollo subsatellite magnetometer data are reviewed using two of the most accurate available magnetic anomaly maps, one covering a portion of the lunar near side and the other a part of the far side. The largest single anomaly found within the region of coverage on the near-side map correlates exactly with a conspicuous light-colored marking in western Oceanus Procellarum called Reiner Gamma. This feature is interpreted as an unusual deposit of ejecta from secondary craters of the large nearby primary impact crater Cavalerius. The mean altitude of the far-side anomaly gap is much higher than that of the near side map and the surface geology is more complex; individual anomaly sources have therefore not yet been identified. The mechanism of magnetization and the origin of the magnetizing field remain unresolved, but the uniformity with which the Reiner Gamma deposit is apparently magnetized, and the north-south depletion of magnetization intensity across a substantial portion of the far side, seem to require the existence of an ambient field, perhaps of global or larger extent.

Hood, L. L.↗

Geological features in Wyoming from Nimbus 1

The identification of ground features in Nimbus photography by comparisons with geology, soils, and vegetation maps is discussed for the Wyoming-Colorado area. It is concluded that in a semiarid region, high topographic relief shows good coassociation with exposed geology and with vegetation and, to a lesser degree, with soils types. In lower, flatter basins, most tonal patterns are related to subtle variations in soil color and vegetation cover. It is thought that maps based on spectral parameters as the proper descriptor of surface features may be required.

Short, N. M.↗

Evaluation of remote sensing in control of pink bollworm in cotton

The use of satellite data from the ERTS-1 satellite for mapping the cotton acreage in the southern deserts of California is discussed. The differences between a growing, a defoliated, and a plowed down field can be identified using an optical color combiner. The specific application of the land use maps is to control the spread of the pink bollworms by establishing planting and plowdown dates.

Coleman, V. B.↗

The Remote Sensing of Mineral Aerosols and Their Impact on Phytoplankton Productivity using Sea WiFS

The main objective of this proposal was to use SeaWiFs data to study the relationship between aerosols found in aeollan dust and photosynthesis of phytoplankton in open ocean surface waters. This project was a collaborative effort between myself and Dr. Neil Tindale at Texas A&M University and followed on our earlier funded proposal which had been designed as a proof-of-concept study to determine if ocean color sensors such as the Coastal Zone Color Scanner (CZCS) could be used to detect and map large-scale mineral aerosol plumes. Despite the large spatial and temporal gaps inherent in the CZCS data coverage, our results from this initial study indicated that an ocean color sensor could indeed be used to detect aerosols. These encouraging results led us to propose in this proposal the use of SeaWiFS data to study mineral aerosol transport and its impact on phytoplankton production. This proposal orignally intended to make use of SeaWiFS images, but as the launch delay of SeaWiFS dragged on, we had to make do with other satellite data sets. Thus, the focus of this proposal became the CSCS image archive instead. I detail my results and accomplishments with this data set.

Stegmann, Petra M.↗

Identification, definition and mapping of terrestrial ecosystems in interior Alaska

The author has identified the following significant results. A reconstituted, simulated color-infrared print, enlarged to a scale of 1:250,000, was used to make a vegetation map of a 3,110 sq km area just west of Fairbanks, Alaska. Information was traced from the print which comprised the southeastern part of ERTS-1 scene 1033-21011. A 1:1,000,000 scale color-infrared transparency of this scene, obtained from NASA, was used along side the print as an aid in recognizing colors, color intensities and blends, and mosaics of different colors. Color units on the transparency and print were identified according to vegetation types using NASA air photos, U.S. Forest Service air photos, and experience of the investigator. Five more or less pure colors were identified and associated with vegetation types. These colors were designated according to their appearances on the print: (1) orange for forest vegetation dominated by broad-leaved trees: (2) gray for forest vegetation dominated by needle-leaved trees; (3) violet for scrub vegetation; (4) light violet denoting herbaceous tundra vegetation; and (5) dull violet for muskeg vegetation. This study has shown, through close examinations of the NASA transparency, that much more detailed vegetation landscape, or ecosystem maps could be produced, if only spectral signatures could be consistently and reliably recognized and transferred to a map of suitable scale.

Anderson, J. H.↗

Applicability of ERTS-1 to Montana geology

The author has identified the following significant results. A detailed band 7 ERTS-1 lineament map covering western Montana and northern Idaho has been prepared and is being evaluated by direct comparison with geologic maps, by statistical plots of lineaments and known faults, and by field checking. Lineament patterns apparent in the Idaho and Boulder batholiths do not correspond to any known geologic structures. A band 5 mosaic of Montana and adjacent areas has been laid and a lineament annotation prepared for comparison with the band 7 map. All work to date indicates that ERTS-1 imagery is very useful for revealing patterns of high-angle faults, though much less useful for mapping rock units and patterns of low-angle faults. Large-scale mosaics of U-2 photographs of three test sites have been prepared for annotation and comparison with ERTS-1 maps. Mapping of Quaternary deposits in the Glacial Lake Missoula basin using U-2 color infrared transparencies has been successful resulting in the discovery of some deposits not previously mapped. Detailed work has been done for Test Site 354 D using ERTS-1 imagery; criteria for recognition of several rock types have been found. Photogeologic mapping for southeastern Montana suggest Wasatch deposits where none shown of geologic map.

Weidman, R. M.↗

Multispectral techniques for general geological surveys evaluation of a four-band photographic system

A general geological survey at 1:62,500 scale of the well exposed rocks of the White Mountains and the adjacent volcanic desert plateau is reported. The tuffs, granites, sedimentary rocks and metavolcanic rocks in this arid region are varicolored and conventional black and white aerial photographs have been a useful mapping aid. A large number of true color and false color aerial photographs and multispectral viewer screen images of the study area are evaluated in order to consider what imagery is the most useful for distinguishing rock types. Photographs of true color film are judged the most useful for recognizing geographic locations.

Crowder, D., F.↗

Land use of northern megalopolis from ERTS-1 imagery

The author has identified the following significant results. A color-coded urban-type land use map of the three northern megalopolitan states of Massachusetts, Connecticut, and Rhode Island has been completed from ERTS-1 images. A computer data bank containing 11 categories of land use for the entire area by 1/4-square-kilometer cells is 80% completed. When completed, the data bank will permit the investigation to proceed to brief analytical studies for completion of the study.

Simpson, R. B.↗

Collection and analysis of remotely sensed data from the Rhode River Estuary Watershed

The remote sensing study to survey the Rhode River watershed for spray irrigation with secondarily treated sewage is reported. The standardization of Autumn coloration changes with Munsell color chips is described along with the mapping of old field vegetation for the spray irrigation project. The interpretation and verification of salt marsh vegetation by remote sensing of the water shed is discussed.

Jenkins, D. W.↗

Concepts of integrated satellite surveys

The United Nations initially contracted with NASA to carry out investigations in three countries; but now as the result of rapidly increasing interest, ERTS imagery has been/is being used in 7 additional projects related to agriculture, forestry, land-use, soils, landforms and hydrology. Initially the ERTS frames were simply used to provide a synoptic view of a large area of a developing country as a basis to regional surveys. From this, interest has extended to using reconstituted false color imagery and latterly, in co-operation with Purdue University, the use of computer generated false color mosaics and computer generated large scale maps. As many developing countries are inadequately mapped and frequently rely on outdated maps, the ERTS imagery is considered to provide a very wide spectrum of valuable data. Thematic maps can be readily prepared at a scale of 1:250,000 using standard NASA imagery. These provide coverage of areas not previously mapped and provide supplementary information and enable existing maps to be up-dated. There is also increasing evidence that ERTS imagery is useful for temporal studies and for providing a new dimension in integrated surveys.

Howard, J. A.↗

Investigation of LANDSAT imagery on correlations between ore deposits and major shield structures in Finland

The author has identified the following significant results. Several regional lineaments appear to correlate with the distribution of ore deposits and showings. Combined study of LANDSAT summer and winter mosaics and color composites of geological, geomorphological, and geophysical maps makes the correlation more perceptible. The revealed pattern of significant lineaments in northern Finland is fairly regular. The most significant lineaments seen in LANDSAT mosaics are not detectable in single images.

Tuominen, H. V.↗

Large scale 20mm photography for range resources analysis in the Western United States

Large scale 70mm aerial photography is a valuable supplementary tool for rangeland studies. A wide assortment of applications were developed varying from vegetation mapping to assessing environmental impact on rangelands. Color and color infrared stereo pairs are useful for effectively sampling sites limited by ground accessibility. They allow an increased sample size at similar or lower cost than ground sampling techniques and provide a permanent record.

Tueller, P. T.↗

Investigation of remote sensing techniques as inputs to operational resource management

The author has identified the following significant results. Visual interpretation of 1:125,000 color LANDSAT prints produced timely level 1 maps of accuracies in excess of 80% for agricultural land identification. Accurate classification of agricultural land via digital analysis of LANDSAT CCT's required precise timing of the date of data collection with mid to late June optimum for western South Dakota. The LANDSAT repetitive nine day cycle over the state allowed the surface areas of stockdams and small reservoir systems to be monitored to provide a timely approximation of surface water conditions on the range. Combined use of DIRS, K-class, and LANDSAT CCT's demonstrated the ability to produce aspen maps of greater detail and timeliness than was available using US Forest Service maps. Visual temporal analyses of LANDSAT imagery improved highway map drainage information and were used to prepare a seven county drainage network. An optimum map of flood-prone areas was developed, utilizing high altitude aerial photography and USGS maps.

Schmer, F. A.↗

Development and usage of a false color display technique for presenting Seasat-A scatterometer data

A computer generated false color program which creates digital multicolor graphics to display geophysical surface parameters measured by the Seasat-A satellite scatterometer (SASS) is described. The data is incrementally scaled over the range of acceptable values and each increment and its data points are assigned a color. The advantage of the false color display is that it visually infers cool or weak data versus hot or intense data by using the rainbow of colors. For example, with wind speeds, levels of yellow and red could be used to imply high winds while green and blue could imply calmer air. The SASS data is sorted into geographic regions and the final false color images are projected onto various world maps with superimposed land/water boundaries.

Jackson, C. B.↗