共查询到20条相似文献,搜索用时 234 毫秒
1.
R R Navalgund V Jayaraman A S Kiran Kumar Tara Sharma Kurien Mathews K K Mohanty V K Dadhwal M B Potdar T P Singh R Ghosh V Tamilarasan T T Medhavy 《Journal of the Indian Society of Remote Sensing》1996,24(4):207-237
Although data available from various earth observation systems have been routinely used in many resource applications, however there have been gaps, and data needs of applications at different levels of details have not been met. There is a growing demand for availability of data at higher repetivity, at higher spatial resolution, in more and narrower spectral bands etc. Some of the thrust areas of applications particularly in the Indian context are;
- Management of natural resources to ensure sustainable increase in agricultural production,
- Study the state of the environment, its monitoring and assessment of the impact of. various development actions on the environment,
- Updating and generation of large scale topographical maps.
- Exploration/exploitation of marine and mineral resources and
- Operational meteorology and studying various land and oceanic processes to understand/predict global climate changes.
- Moderate spatial resolution (l50-300m), high repetivity (2 Days), minimum set of spectral bands (VIS, NIR, MIR. TIR) full coverage.
- Moderate to high spatial resolution (20-40m), high repetivity (4-6 Days), spectral bands (VIS, MR, MIR, TIR) full coverage.
- High spatial resolution (5-10m) muitispectral data with provision for selecting specific narrow bands (VIS, N1R. MIR), viewing from different angles.
- Synthetic aperture radar operating in at least two frequencies (C, X, Ku), two incidence angles/polarizations, moderate to high spatial resolution (20-40m), high repetivity (4-6 Days).
- Very high spatial resolution (1-2m) data in panchromatic band to provide terrain details at cadastral level (1:10,000).
- Stereo capability (1-2m height resolution) to help planning/execution of development plans.
- Moderate resolution sensor operating in VIS, NIR, MIR on a geostationary platform for observations at different sun angles necessary for the development of canopy reflectance inversion models.
- Diurnal (at least two i.e. pre-dawn and noon) temperature measurements of the earth surface.
- Ocean colour monitor with daily coverage.
- Multi-frequency microwave radiometer, scatterometer. altimeter, atmospheric sounder, etc.
2.
For the following problems - estimating the statistical parameters of the precise levelling, - adjusting the primary levelling networks and - estimating vertical crustal movements mathematical models are being sketched out. Results obtained in evaluating primary relevellings in the G.D.R. are reported. 相似文献
3.
Warren G. Heller 《Journal of Geodesy》1981,55(4):354-369
The state of current and proposed moving-base gravity gradiometer instruments is briefly reviewed. The review perspective is directed toward their deployment as a source of additional gravimetric data during inertial surveys. In such gradiometer-aided surveys, the additional gravity gradient information could be used to:
- Improve surveyed gravity vector accuracy
- Extend the interval between zero velocity update stops
- Accomplish varying combinations of the above.
4.
Morphometric analysis of a drainage basin using aerial photographs: A case study of Khairkuli basin,district Dehradun,U.P. 总被引:1,自引:0,他引:1
M. D. Nautiyal 《Journal of the Indian Society of Remote Sensing》1994,22(4):251-261
Remote sensing techniques using satellite images and aerial photographs are convenient tools in morphometric analysis of a drainage basin. In the present study morphometric parameters of Khairkuli drainage basin, district Dehradun, are worked out using aerial photographs. The parameters worked out include bifurcation ratio, stream length, form factor, circulatory ratio, elongation ratio, drainage density, constant of channel maintenance and stream frequency. Hypsometric relations of drainage basin are also presented. Relation between cumulative stream length and the stream order establishes that the ratio between cumulative stream length Σ 1 u Σ 1 nu Lu and the stream order u is constant throughout the. successive orders of a drainage basin suggesting that geometrical similarity is preserved in the basins of increasing order. The morphometric parameters computed suggest that the area is covered by resistant permeable rocks (with fracture and karstic porosities) and vegetative cover, the drainage network is affected by tectonic disturbances. The peak flows generated from the basin are likely to be moderately high and of short duration. 相似文献
5.
A sequential adjustment procedure is proposed for the direct estimation of point—velocities in deformation analysis networks. At any intermediate stage of the adjustment the up-to-date covariance matrix of those velocities tells the evolving story of the network in terms of solvability and reliability. A pre-zero-epoch covariance matrix is utilized for a smooth and flexible treatment of two characteristic problems of deformation analysis: - high turnover of points in the network - processing variable and generally incomplete observational batches. A small numerical example is presented at the end as an illustration. 相似文献
6.
Geological studies in the area around Badami, Bijapur District, Karnataka, were carried out with the help of Landsat imagery and aerial photographs. The study are forms a part Kaladgi Basin which is located on the northernmost fringes of the exposed Dharwar Craton. Archaen Peninsular Gneiss and intrusive Granodiorite/Granites (≈Clospet Granite) form the basement for the Middle to Late Proterozoic Kaladgi Super Group sediments which are, in turn, overlain in the north by the Upper Cretaceous to Lower Eocene Deccan flood basalt lavas. Geological mapping of the study area and inferences about the structural setup were primarily based on interpretation of the remotely sensed data. The combined interpretative study of Landsat imagery and aerial photographs was instrumental in mapping of the lithostratigraphic units exposed in the study area along with the structures associated with them. 相似文献
7.
J. J. Levallois 《Journal of Geodesy》1983,57(1-4):312-331
The French astronomerJean PICARD (1620–1682) was certainly one of the leading scientists of his time. Friend of Huygens, of Hevelius, of Oldenburg, master of Römer, indefatigable traveller, he played a very important part in the development of positional astronomy and geodesy. - He first, had the idea of comparing the length units to a reproductible physical quantity, namely the length of the one second pendulum at Paris, and measured that length. - He conceived the first cross wire telescopes and adapted them on geodetic and astronomical instruments of his own, used throughout one century until 1780. - He obtained the first really reliable value of the earth radius, in his famous measurement of the meridional arc PARIS-AMIENS, being the original cell of the French triangulations. The following article is devoted to a recomputation and evaluation of the accuracy of that work, as compared with further operations, but independently concludes that this achievement gave the necessary impulse to the development of geodesy in France and probably abroad. 相似文献
8.
Wasteland map (1∶100,000) of Rewasa catchment (Sikar district) has been prepared using aerial photographs and Landsat TM imagery. Thematic Mapper data were helpful in identifying the types of wastelands and details could be derived from the aerial photographs. The types of wastelands identified are sands, gullied land, salt affected areas, and barren rocky area. Depending upon the nature of wasteland, suitable rehabilitation measures like plantations, afforestation have been proposed. 相似文献
9.
Johannes Ihde 《Journal of Geodesy》1981,55(2):99-110
The investigations refer to the compartment method by using mean terrestrial free air anomalies only. Three main error influences of remote areas (distance from the fixed point >9°) on height anomalies and deflections of the vertical are being regarded:
- The prediction errors of mean terrestrial free air anomalies have the greatest influence and amount to about ±0″.2 in each component for deflections of the vertical and to ±3 m for height anomalies;
- The error of the compartment method, which originates from converting the integral formulas of Stokes and Vening-Meinesz into summation formulas, can be neglected if the anomalies for points and gravity profiles are compiled to 5°×5° mean values.
- The influences of the mean gravimetric correction terms of Arnold—estimated for important mountains of the Earth by means of an approximate formula—on height anomalies may amount to 1–2 m and on deflections of the vertical to 0″0.5–0″.1, and, therefore, they have to be taken into account for exact calculations.
10.
Georges Blaha 《Journal of Geodesy》1982,56(4):281-299
The present paper deals with the least-squares adjustment where the design matrix (A) is rank-deficient. The adjusted parameters \(\hat x\) as well as their variance-covariance matrix ( \(\sum _{\hat x} \) ) can be obtained as in the “standard” adjustment whereA has the full column rank, supplemented with constraints, \(C\hat x = w\) , whereC is the constraint matrix andw is sometimes called the “constant vector”. In this analysis only the inner adjustment constraints are considered, whereC has the full row rank equal to the rank deficiency ofA, andAC T =0. Perhaps the most important outcome points to the three kinds of results
- A general least-squares solution where both \(\hat x\) and \(\sum _{\hat x} \) are indeterminate corresponds tow=arbitrary random vector.
- The minimum trace (least-squares) solution where \(\hat x\) is indeterminate but \(\sum _{\hat x} \) is detemined (and trace \(\sum _{\hat x} \) corresponds tow=arbitrary constant vector.
- The minimum norm (least-squares) solution where both \(\hat x\) and \(\sum _{\hat x} \) are determined (and norm \(\hat x\) , trace \(\sum _{\hat x} \) corresponds tow?0
11.
M. G. Sideris 《Journal of Geodesy》1996,70(8):470-479
Spectral methods have been a standard tool in physical geodesy applications over the past decade. Typically, they have been used for the efficient evaluation of convolution integrals, utilizing homogeneous, noise-free gridded data. This paper answers the following three questions:
- Can data errors be propagated into the results?
- Can heterogeneous data be used?
- Is error propagation possible with heterogeneous data?
12.
Observable quantities in satellite gradiometry 总被引:1,自引:1,他引:0
Martin Vermeer 《Journal of Geodesy》1990,64(4):347-361
Deriving the observables for satellite gravity gradiometry, several workers have identified the invariants under spatial rotation of the gravitation gradient tensor for obtaining quantities insensitive to the precise (unrecoverable) attitude of the satellite. Extending this work we show:
- Considering that an approximate (not precise) attitude recovery for these, three-axes-stabilised, satellites is to be expected, one can identifythree independent invariants instead of two.
- Besides studying gradient tensor invariants for one observation time, one should also study (as withGPS observables) first and seconddifferences between successive tensor component values in time. Bias and trend patterns in the measured tensor components caused by satellite rotation uncertainty, and by attitude uncertainty in some cross components, are shown to cancel. Information thus obtained is exclusively high-frequency, however.
13.
本文讨论了以热带森林植被为主体的再生资源的面积动态变化监测。研究中包括两个部分。首先,我们利用多时相遥感图像对大面积的西双版纳州进行地类判读,系统地分析了森林植被的动态变化。其次,利用Landsat MSS和TM数据对自然保护区的动态变化进行了包含无监督分类和归一化差值植被指数分析的数字图像处理,变化分类也相当符合实际。总的实验结果表明,这种监测方法是很有效的,可在再生资源监测中特别是在森林植被监测中加以推广应用。 相似文献
14.
K. P. Sharma P. K. Garg S. K. Verma 《Journal of the Indian Society of Remote Sensing》1986,14(1):11-16
To utilize the full potential of multispectral data acquired from aerial photographs/satellite imagery increased knowledge of the spectral reflectance characteristics of Landuse/Landcover features are required. Spectro-Radiometer was used to collect the spectral reflectance values in wavelength regions ranging from 0.48 to 0.96 u m, of some Landuse/Landcover features, in Roorkee and its surrounding areas. Spectral reflectance values, thus collected, were used to draw spectral reflectance curves of each feature separately and to determine the optimum wavelength regions for identifying each Landuse/Landcover feature. The wavelength regions, in which two dissimilar Landuse/Landcover features exhibit nearly same tonal variation in B&W aerial photographs/satellite imagery, were also determined from these curves. 相似文献
15.
Combining consecutive short arcs into long arcs for precise and efficient GPS Orbit Determination 总被引:1,自引:1,他引:0
G. Beutler E. Brockmann U. Hugentobler L. Mervart M. Rothacher R. Weber 《Journal of Geodesy》1996,70(5):287-299
The final products of theCODE Analysis Center (Center for Orbit Determination in Europe) of theInternational GPS Service for Geodynamics (IGS) stem fromoverlapping 3-day-arcs. Until 31 December, 1994 these long arcs were computedfrom scratch, i.e. by processing three days of observations of about 40 stations (by mid 1995 about 60 stations were used) of the IGS Global Network in our parameter estimation program GPSEST. Becauseone-day-arcs have to be produced first (for the purpose of error detection etc.) the actual procedure was rather time-consuming. In the present article we develop the mathematical tools necessary to form long arcs based on the normal equation systems of consecutive short arcs (one-day-solutions in the case of CODE). The procedure in its simplest version is as follows:
- Each short arc is described bysix initial conditions and a number of dynamical orbit parameters (e.g. radiation pressure parameters). The resulting long arc in turn shall be based onn consecutive short arcs and described bysix initial conditions and again the same number of dynamical parameters as in the short arcs..
- By asking position and velocity to be continuous at the boundaries of the short arcs we obtain a long arc which is actually defined by one set of initial conditions andn sets of dynamical parameters (ifn short arcs are combined)..
- By asking the dynamical parameters to be identical in consecutive short arcs, the resulting long arc is characterized by exactly the same number of orbit parameters as each of the short arcs.
- This procedure isnot yet optimized becauseformally all n sets of orbit parameters have to be set up and solved for in the long arc solution (although they are not independent). In order to allow for an optimized solution we derive all necessary relations to eliminate the unnecessary parameters in the combination. Each long arc is characterized by the actual number of independent orbit parameters. The resulting procedure isvery efficient.
16.
Christopher Potter Peggy Gross Vanessa Genovese Marie-Louise Smith 《Carbon balance and management》2007,2(1):1-11
Background
A simulation model that relies on satellite observations of vegetation cover from the Landsat 7 sensor and from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate net primary productivity (NPP) of forest stands at the Bartlett Experiment Forest (BEF) in the White Mountains of New Hampshire.Results
Net primary production (NPP) predicted from the NASA-CASA model using 30-meter resolution Landsat inputs showed variations related to both vegetation cover type and elevational effects on mean air temperatures. Overall, the highest predicted NPP from the NASA-CASA model was for deciduous forest cover at low to mid-elevation locations over the landscape. Comparison of the model-predicted annual NPP to the plot-estimated values showed a significant correlation of R2 = 0.5. Stepwise addition of 30-meter resolution elevation data values explained no more than 20% of the residual variation in measured NPP patterns at BEF. Both the Landsat 7 and the 250-meter resolution MODIS derived mean annual NPP predictions for the BEF plot locations were within ± 2.5% of the mean of plot estimates for annual NPP.Conclusion
Although MODIS imagery cannot capture the spatial details of NPP across the network of closely spaced plot locations as well as Landsat, the MODIS satellite data as inputs to the NASA-CASA model does accurately predict the average annual productivity of a site like the BEF. 相似文献17.
In the vast alluvial plains of West Bengal and Orissa several deltaic plains exist, occurring in an off-lap sequence. These deltas were formed in the background of eustatic fluctuations during the Quaternary Period. They were built partly during rising sea level and pertly during stationary sea level stages. Landform analysis through aerial photographs as well as Landsat imagery interpretation, attested by field study, helped to establish the palaeogeomorphology of these Quaternary deltas. Possible mode of sedimentation during different phases of sea level fluctuations has been worked out 相似文献
18.
S. C. Sharma N. Rajendran A. K. Grover G. S. Srivastava 《Journal of the Indian Society of Remote Sensing》1990,18(4):45-64
The paper describes the details of a comparative study of geological interpretations carried out from Synthetic Aperture Radar (SAR) imagery, Landsat MSS (B & W) imagery and Aerial Photographs, covering 2100 sq km of area in Anantapur district of Andhra Pradesh. The area comprises Peninsular—Gneissic Complex and rocks of Dharwar and Cuddapah Super Groups beside the Quaternary alluvial deposits along the Penneru river and its tributaries. Geomorphologically the areas is represented by denudational, fluvial and structural landforms. The study indicates that the details of the geological and geomorphological maps prepared from SAR imagery and aerial photographs are comparable despite the smaller scale of SAR imagery while the same are not exhibited in Landsat imagery mainly due to its low resolution. Although broad lithological units are possible to be discriminated on SAR as well as aerial photographs, some of the finer rock types viz. gabbroic dykes could be discriminated from the delerite dykes in the SAR imagery due to their different surface roughness. Stereoscopic coverage and enhanced micro-relief of SAR imagery gives better geomorphological details in comparison to aerial photographs. A detailed study of lineaments has also been carried out which shows that in SAR imagery there is over-representation of short lineaments due to enhanced micro-relief and radarshadow effects across the look direction and under-representation of lineaments along the look direction. Landsat imagery is perhaps the best for demarcating lineaments of regional magnitude while aerial photographs are good for depicting shorter lineaments. However, certain lineaments seen in SAR imagery are often not continuously seen on aerial photographs. 相似文献
19.
20.
Remotely-sensed data products have got unique advantage over conventional data-gathering techniques in the study of urban morphology. The physical parameters like built-up area density, street pattern, population density, urban structure as well as functional characteristics which can be derived from land use/land cover map, are clearly visible on aerial data products. This technique provides synoptic view of the area which makes the study comprehensive and uniform. Sequential aerial photographs and satellite imagery help in studying the growth of urban area and temporal changes in urban structure. These informations are very useful in the planning of city extension. Here an attempt has been made to study the urban morphology of Saharanpur city by using panchromatic aerial photographs on scale 1∶10,000, IRS-1B LISS II geocoded imagery on 1∶50,000 scale and photo-maps on 1∶4000 scale, and the results are very encouraging. 相似文献