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 共查询到20条相似文献，搜索用时 31 毫秒
1.
《The Cartographic journal》2013,50(2):121-126
Abstract

In order to display, predict and combat atmospheric pollution, suitable graphics should be employed. The author proposes some new methods of representation such as mapping air pollution on an air photograph which is printed through screens proportional to air purity, or using the Polyfocal Projection for mapping airport noise. Polar diagrams are used to depict atmospheric stability states.  相似文献   

2.
《测量评论》2013,45(64):71-83
Abstract

During the last thirty years, developments in the taking of air photographs (and of mapping from them) have been progressive until, under present day conditions, no programme of topographical mapping for economic development can be satisfactorily undertaken without using them.  相似文献   

3.
《测量评论》2013,45(71):13-15
Abstract

Early in 1946 a Central Survey organisation was set up with headquarters in London to undertake, in conjunction with the R.A:F., the air survey mapping of large areas of the Colonial Empire, in connection with Colonial Development programmes.  相似文献   

4.
《测量评论》2013,45(84):278-279
Abstract

Many methods of mapping from air photographs “without control” have been proposed from time to time. Usually this means having no control, or very little, on the ground. The following paper describes some experiences of mapping without controlling the photographs inter se, a suggestion which must rank as improper with a Photogrammetrist.  相似文献   

5.
Abstract

This account of exploratory mapping is provided by a surveyor who started his working life as an explorer in areas where existing maps were extremely rough and rudimentary. Although the methods and results it describes will not stand comparison with modern topographical maps compiled from vertical air photographs, this frank and objective appraisal will help the 'chair-borne' cartographer to understand the importance of a thorough evaluation of some material of that type and age, which is still sometimes the best available until the new air surveys replace it.  相似文献   

6.
《测量评论》2013,45(35):270-274
Abstract

An instrument was previously described in the Transactions of the Royal Society of S. Africa for the setting of pairs of photographs, taken from air stations, in correspondence; that is, in the same relative positions that the camera occupied in space at the moments of exposure. The principle of the instrument may be recalled.  相似文献   

7.
《测量评论》2013,45(48):59-68
Abstract

“RECTIFICATION” is the term used to describe the production from a tilted air photograph of a print or image from which the effects of tilt have been eliminated. It consists, essentially, in the projection of the original photograph on to another selected planenormally, but not necessarily, representing the horizontal.  相似文献   

8.
《测量评论》2013,45(27):272-275
Abstract

Accidents will happen and the surveyor is therefore sometimes required to do the best he can with photographs taken with an uncalibrated camera which is not available for subsequent calibration. This note outlines a method by which an approximate principal distance can be obtained for high oblique air photographs from points appearing in the photographs.  相似文献   

9.
《测量评论》2013,45(73):119-130
Abstract

1. This new method of adjusting air photographs numerically to a uniform scale on a final map grid has already been described by the writert, where it concerns a large block-adjustment. The method to be described in this paper is the application of the same principle to the adjustment of photographic strips, covering narrow land areas and coastlines.  相似文献   

10.
《测量评论》2013,45(76):242-255
Abstract

During the last year, the Air Survey Section, Field Division, Ordnance Survey, have had many visitors. Most of them have been surprised at what they have seen: some at the fact that we are able to make so much use of air photographs even in the largest scale surveys, and some at the small amount of information we seem able to extract from them. This paper is an attempt to give in some detail the ways in which air photographs are used to solve the problems of the Ordnance Survey, why they are used and their limitations for our purposes.  相似文献   

11.
《测量评论》2013,45(77):306-314
Abstract

Lieut.-Col. Browne's interesting method of combii1ing radial line plots (“The Application of Transformation Factors to the Adjustment of Air Photographs”, E.S.R., x, 73, 119-130) depends for its success on the basic accuracy of the radial line plots of the individual air photo strips. It therefore poses the very interesting question: What accuracy can we expect in a graphical radial line plot?  相似文献   

12.
《测量评论》2013,45(96):70-75
Abstract

The following paper describes some of the results obtained on it, tour of the Katsina and Kano Provinces of Northern Nigeria between November 1953 and February 1954. The purpose of the tour was to obtain latitudes and longitudes by astronomical observations for air photo mapping control in the northern parts of these provinces where triangulation is not available. The area is mostly flat and sandy.  相似文献   

13.
《测量评论》2013,45(19):272-277
Abstract

The application of the formulae for the rectification of air photographs, with or without change of scale, becomes greatly simplified when the tilt of the photographs is small. Usually this tilt does not exceed 2°, and the rectification may take place in a comparatively simple form of camera and with hardly any computations, since, as will be shown, variations of the camera settings are then accurately linear in relation to the tilt. It will also be shown that in the result the errors due to small differences in the focal length of the air camera lenses, to distortion from the pressure plate, and to average shrinkage of the film, can be automatically eliminated.  相似文献   

14.
《测量评论》2013,45(10):206-221
Abstract

4.3. Having found s we may proceed to obtain the coordinates of the air station. This is the vertex of a pyramid, the base edges being of lengths a, b, c and the opposite edges measuring u, v, w respectively. Let h be the distance of the vertex from the plane of the base, and suppose d, e1 e2, e3 are respectively twice the areas of the base and of the oblique faces in order.  相似文献   

15.
《测量评论》2013,45(82):163-177
Abstract

The method outlined below is a simple and rapid method, requiring no expensive equipment, of obtaining true heights from pairs of near vertical air photographs with a minimum of ground control. It is a direct application of the Fourcade theorem and, as it was finally developed at the University of the Witwatersrand in 1948-49, it has been given the name “Rand method” in the hope that this will connect it with Dr. Fourcade's country.  相似文献   

16.
《测量评论》2013,45(9):137-150
Abstract

The paper describes an algebraic method of forming linear equations, giving the coordinates of points in space in terms of the coordinates of their images on the photographic plates. The coefficients which enter into these linear equations form a matrix of the third order. When stereoscopic or similar methods are used for plotting detail, the elements of this matrix give in a convenient form and with the utmost obtainable accuracy the quantities required for setting the photographs in their correct relation to the map and to one another.

An easy and rapid graphical method of obtaining good approximations to all the solutions of the problem of resection in space is described. A method of refining the solutions is given. When the coordinates of the air station are known with fair accuracy an alternative procedure is described. In the absence of ground control suitable for finding the air station by resection a method of eliminating most of the uncertain quantities is obtained. The indeterminate quantities relate to strip photographs as a whole and not to individual photographs. A method of dealing with the coefficients for the complete strip is described.

In finding air stations by resection, point-coordinates in the photographs must be converted into directional coordinates. In other calculations this transformation is unnecessary.  相似文献   

17.
Abstract

When Lord Kitchener ordered Sir Ian Hamilton in 1915 to command land operations on Gallipoli he gave him a solitary old One Inch map and denied him any air forces. When Winston Churchill had earlier sent the Royal Navy to break through to the Black Sea, he had ensured that the Royal Naval Division withdrawn from fighting on the Western Front was accompanied by a Naval Air Squadron as its forward reconnaissance element. Ernest Dowson, the Surveyor General of Egypt, appointed to provide local mapping support, soon convinced the Naval pilots of the value of air photography taken systematically to meet his map-making requirements. In September 1915 Dowson wrote a Secret technical report demonstrating for the first time to British Commanders the practicality of mapping from specified aeroplane photographs of the operational area.  相似文献   

18.
ABSTRACT

The reliable and robust monitoring of air temperature distribution is essential for urban thermal environmental analysis. In this study, a stacking ensemble model consisting of multi-linear regression (MLR), support vector regression (SVR), and random forest (RF) optimized by the SVR is proposed to interpolate the daily maximum air temperature (Tmax) during summertime in a mega urban area. A total of 10 geographic variables, including the clear-sky averaged land surface temperature and the normalized difference vegetation index, were used as input variables. The stacking model was compared to Cokriging, three individual data-driven methods, and a simple average ensemble model, all through leave-one-station-out cross validation. The stacking model showed the best performance by improving the generalizability of the individual models and mitigating the sensitivity to the extreme daily Tmax. This study demonstrates that the stacking ensemble method can improve the accuracy of spatial interpolation of environmental variables in various research fields.  相似文献   

19.
Abstract

As a key component of digital earth, remotely sensed data provides the compelling evidence that the amount of water vapour transferred from the entire global surface to the atmosphere increased from 1984 to 2007. The validation results from the earlier evapotranspiration (ET) estimation algorithm based on net radiation (R n ), Normalised Difference Vegetation Index (NDVI), air temperature and diurnal air temperature range (DTaR) showed good agreement between estimated monthly ET and ground-measured ET from 20 flux towers. Our analysis indicates that the estimated actual ET has increased on average over the entire global land surface except for Antarctica during 1984–2007. However, this increasing trend disappears after 2000 and the reason may be that the decline in net radiation and NDVI during this period depleted surface soil moisture. Moreover, the good correspondence between the precipitation trend and the change in ET in arid and semi-arid regions indicated that surface moisture linked to precipitation affects ET. The input parameters R n , T air, NDVI and DTaR show substantial spatio-temporal variability that is almost consistent with that of actual ET from 1984 to 2007 and contribute most significantly to the variation in actual ET.  相似文献   

20.
ABSTRACT

The automated classification of ambient air pollutants is an important task in air pollution hazard assessment and life quality research. In the current study, machine learning (ML) algorithms are used to identify the inter-correlation between dominant air pollution index (API) for PM10 percentile values and other major air pollutants in order to detect the vital pollutants’ clusters in ambient monitoring data around the study area. Two air quality stations, CA0016 and CA0054, were selected for this research due to their strategic locations. Non-linear RPart and Tree model of Decision Tree (DT) algorithm within the R programming environment were adopted for classification analysis. The pollutants’ respective significance to PM10 occurrence was evaluated using Random forest (RF) of DT algorithms and K means polar cluster function identified and grouped similar features, and also detected vital clusters in ambient monitoring data around the industrial areas. Results show increase in the number of clusters did not significantly alter results. PM10 generally shows a reduction in trend, especially in SW direction and an overall minimal reduction in the pollutants’ concentration in all directions is observed (less than 1). Fluctuations were observed in the behaviors of CO and NOx during the day while NOx displayed relative stability. Results also show that a direct and positive linear relationship exists between the PM10 (target pollutant) and CO, SO2, which suggests that these pollutants originate from the same sources. A semi-linear relationship is observed between the PM10 and others (O3 and NOx) while humidity shows a negative linearity with PM10. We conclude that most of the major pollutants show a positive trend toward the industrial areas in both stations while tra?c emissions dominate this site (CA0016) for CO and NOx. Potential applications of nuggets of information derived from these results in reducing air pollution and ensuring sustainability within the city are also discussed. Results from this study are expected to provide valuable information to decision makers to implement viable strategies capable of mitigating air pollution effects.  相似文献   

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