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1.
Crime on the edges: patterns of crime and land use change   总被引：1，自引：0，他引：1  
ABSTRACT

Criminologists have long-known that different locations have varying levels of risk for criminal victimization. Based on the geometry of crime and its corresponding crime generators and crime attractors, edges (boundaries between relatively homogeneous neighborhoods) are locations with an elevated risk of criminal victimization. In this article, we investigate the importance of edges. We find that criminal victimization rates are 2–3 times on an edge compared to elsewhere. However, this effect decreases very quickly moving away from these locations, with the effect gone at 40 meters. This general effect is identified in a number of contexts and locations.  相似文献   

2.
Abstract

The transition and restructuring process of urban South Africa are currently in the phase of identifying land development objectives. These objectives aim to integrate previously segregated areas through integrated development plans. This research aims firstly to identify and describe the historical development of the spatial form and structure of the secondary city and capital of the Northern Province, Pietersburg and its dispersed peripheral towns. Supervised classification of SPOT HRV multispectral imagery is used to support the theoretical explanation. Images from an airborne digital Kodak DCS 420 camera are used to provide training sites in the pre‐classification stages, and also provide field data to the process of post‐classification accuracy assessment. Secondly, SPOT HRV imagery is applied to identify the stark contrast in urban development between the city of Pietersburg and its surrounding former homeland towns. Both built and natural environmental aspects are investigated. In conclusion benefits and problems of assessing urban morphology and development in a developing country by means of a combination of satellite imagery and digital aerial photography are discussed.  相似文献   

3.
ABSTRACT

Quantitative attribution at the individual pixel level of the relative contributions of climate variability and human activities to vegetation productivity dynamics across Africa is generally lacking. This is because of the difficulty in establishing a baseline or potential vegetation against which the relative impacts of these factors can be assessed. This study addresses these gaps. First, annual potential net primary productivity (NPPP) for 2000–2014 was estimated for Africa using a model constructed from samples of NPP and environmental covariates from protected areas. Second, trends in NPPP, actual NPP (NPPA), and human-appropriated NPP (NPPH?=?NPPP ? NPPA) were estimated and used in quantifying the relative contributions of climate and human activities to NPP dynamics. Over 2000–2014, NPP improvement was largely concentrated in equatorial and northern Africa, while subequatorial Africa exhibited the most NPP decline. Parts of Mali, Burkina Faso, and the central Africa region are associated with the greatest influence of climate-driven NPP improvement. Areas where humans dominated NPP decline include parts of Ethiopia and South Africa. Climate had a stronger role in driving NPP decline in subequatorial Africa. Nonetheless, further work is required to validate the results of this study with high-resolution imagery and field information.  相似文献   

4.
《测量评论》2013,45(7):2-6
Abstract

On returning from Central Africa I was posted, for ordinary duty, to Edinburgh, and after a short time I found myself again on the Ordnance Survey. Late in 1899 the South African War broke out, and early in 1900 I was sent out to South Africa in command of a very small Field Survey Section. But before describing the limited activities of this Section it may be as well to give some idea of the attitude of the higher civil and financial authorities towards the proposition that it is desirable to be prepared with maps of possible theatres of war.  相似文献   

5.
基于GIS方法,对广州市禁摩前和禁摩后两个时间段的抢劫盗窃犯罪案件数据,进行点模式描述和点模式分析。分析结果表明:禁摩前后广州市抢劫盗窃犯罪的案发地点在空间位置和空间范围上发生了很大变化。空间位置整体向东北方向移动,空间范围进一步扩张,由禁摩前的东西走向变为向西北和东南两个方向延伸;同时,禁摩后的空间聚集程度也有所降低。这些变化都进一步说明了,新时期下,这类犯罪呈现出了新的时空变化特征。  相似文献   

6.
Abstract

People are now using geoinformation for many different purposes and consequently one can confidently say that the need for geospatial data infrastructure (GDI) cannot be overstated in sub-Saharan Africa. Geospatial information (GI) is essential to socio-economic planning and development of sub-Sahara African countries. This paper therefore examines: GI during the last centuries in sub-Sahara Africa; recent paradigms in GDI in sub-Sahara Africa; the benefit of GDI to the African economy and the future of GDI in sub-Sahara Africa. This study discovered that most countries in sub-Saharan Africa did not have timely access to accurate geospatial data throughout the last centuries. This significantly hindered meaningful social and economic development. Development of GDI nonetheless, will enhance search and retrieval of geospatial data in Africa. This is one of the benefits that can be derived from implementing GDI in sub-Sahara Africa. Therefore, it is necessary to review cadastral survey laws and regulations so as to incorporate the use of recent geospatial equipment.  相似文献   

7.
《测量评论》2013,45(82):159-163
Abstract

This project, which is now well known to surveyors not only in Africa but all over the world, was first visualised by Sir David Gill, who for many years was H.M. Astronomer at the Cape Observatory. It is fitting to commence by giving in his own words his conception of the work, the part of which from South Africa to the Equator has now been completed. The following extracts are taken from the paper “On the Origin and Progress of Geodetic Survey in South Africa, and of the African Arc of Meridian”, by Sir David Gill,K.C.B., F.R.S.  相似文献   

8.
《测量评论》2013,45(18):203-218
Abstract

The gear used for the measurement of the Kate Base of the East African Arc was specially designed by McCaw in conjunction with Messrs. Cooke, Troughton, & Simms, as a result of considerable experience in the measurement of geodetic bases in Fiji, Sweden, and in various parts of Africa; it is now known by the trade name of the “Macca” Base Measurement Gear. It has since been used in Southern Rhodesia, Tanganyika, Mauritius, and South Africa, and if the central pool of instruments recommended at the recent Empire Surveyors Conference is approved, it seems likely that its beat will soon be still more extended. It must be about the only first model of a surveying instrument which has not occasioned widespread controversy and complaint, and for this desirable state of affairs it is not unreasonable to suppose that the rare co-operation between the practical surveyor and the instrument-maker in its design is responsible.  相似文献   

9.
ABSTRACT

Relocating people in informal settlements and upgrading the lives of those people require consistent commitment, good strategies, and supporting systems. In South Africa, in order to allocate subsidized housing to beneficiaries of an informal settlement, beneficiary administration needs to determine the number of people who qualify for subsidized houses. Without geo-spatial data-based technical verification, conventional methods of occupancy audits are often cumbersome, are unreliable, and do not promote smart and evidence-based decision making. Accordingly, the aim of this study is to propose and develop an Oracle-based mobile GIS tool to conduct an occupancy audit for Ulana, an informal settlement in Ekurhuleni Municipality in South Africa. Android-based tablets were used to collect the geographic and socio-economic attributes of the informal dwelling units (DU). Spatial analysis (in ArcGIS software and geo-spatial modeling environment) and statistical analysis were conducted to produce the occupancy audit. The results indicated that the use of mobile GIS provides up-to-date, accurate, comprehensive, and real-time data so as to facilitate the development of smart and integrated human settlements. The results of this audit also indicated that only 57% of the households residing in Ulana could potentially benefit from receiving a subsidized house. Accordingly, the occupancy audit enables planners to plan appropriate upgrading and housing development strategies for informal settlement. This study demonstrates that successful planning of housing delivery for post independent integrated neighborhoods is not a mere political rhetoric but is viable when it is based on reasonable geo-spatial techniques and information. The use of mobile GIS therefore needs to be extended to other informal settlement upgrading projects in South Africa as well as other cities in the global south. However, proper professional training is required to ensure the successful usage of smart mobile GIS tools.  相似文献   

10.
Abstract

The content of topographic and planimetric maps in relation to vegetation is examined with reference to the evaluation of contouring, the degree to which vegetation impedes movement, forestry, recreation, the planning of development projects, route planning, vegetation as base map information, and land use. This is an extension of the paper published in the Cartographic Journal, vol. 2, no. 2, and refers in particular to Africa South of the Sahara.  相似文献   

11.
《测量评论》2013,45(48):50-56
Abstract

In the memoir of the late Capt. G. T. McCaw which appeared in the January number of this Review (vii, 47,2), reference was made to the part which the late Sir David Gill played in the origin of the work on the survey of the Arc of the 30th Meridian in Africa. This year is the centenary of Gill's birth, as he was born in June 1843, and it is therefore timely to give some account of his work during his long term of office as Her Majesty's Astronomer at the Cape which resulted inthe inception and completion of the Geodetic Survey of South Africa and the survey of the Arc to the southern shores of Lake Tanganyika. He died on 24th January 1914.  相似文献   

12.
《测量评论》2013,45(85):319-325
Abstract

In a recent issue of this Review, an example is given of the conformal transformation of a network of triangulation using Newton's interpolation formula with divided differences. While the application of the method appears to be new, attention should be drawn to the fact that Kruger employed Lagrange's interpolation formula in a discussion and extension of the Schols method in a paper which was published in the Zeitschrift für Vermessungswesen in 1896. A reference to this paper was given at the end of the paper, “Adjustment of the Secondary Triangulation of South Africa”, published in a previous issue of the E.S.R. (iv, 30, 480).  相似文献   

13.
《测量评论》2013,45(91):222-226
Abstract

This discussion relates to the use by the Trigonometrical Survey of South Africa of Wild photogrammetric equipment in the compilation of 1/18,000 topographical maps from 1/30,000 photographs and to the accuracy of the work found thus far by field check. The equipment used, the field and compilation methods and the specifications for the work are briefly described in this article.  相似文献   

14.
ABSTRACT

Urban areas presently consume around 75% of global primary energy supply, which is expected to significantly increase in the future due to urban growth. Having sustainable, universal energy access is a pressing challenge for most parts of the globe. Understanding urban energy consumption patterns may help to address the challenges to urban sustainability and energy security. However, urban energy analyses are severely limited by the lack of urban energy data. Such datasets are virtually non-existent for the developing countries. As per current projections, most of the new urban growth is bound to occur in these data-starved regions. Hence, there is an urgent need of research methods for monitoring and quantifying urban energy utilization patterns. Here, we apply a data-driven approach to characterize urban settlements based on their formality, which is then used to assess intra-urban urban energy consumption in Johannesburg, South Africa; Sana’a, Yemen; and Ndola, Zambia. Electricity is the fastest growing energy fuel. By analyzing the relationship between the settlement types and the corresponding nighttime light emission, a proxy of electricity consumption, we assess the differential electricity consumption patterns. Our study presents a simple and scalable solution to fill the present data void to understand intra-city electricity consumption patterns.  相似文献   

15.
《The Cartographic journal》2013,50(3):237-248
Abstract

Since 1906, South Africa boasted an excellent geodetic framework, and in 1920 an official Trigonometrical Survey Office (TSO) was established. In spite of these achievements, the country, by the 1930s, still lacked reliable topographical maps. One reason for this was that the secondary and tertiary triangulations of the country were still incomplete; another was that the decision-making process as regards surveys and mapping rested with a variety of statutory bodies instead of just one. In 1934, A. D. Lewis, Director of the Department of Irrigation, committed his department to execute a general topographical survey of the country and produce a topographical map on a scale of 1∶500?000. Lewis’ decision met with much resistance from within the country and abroad, but the project was completed in a record period of 4 years. Published just before the Second World War, the map was of inestimable value to the South African Defense Force. It not only became the standard topographical map of large parts of South Africa for many years, but its contents also figured in the first map series of the TSO.  相似文献   

16.
《测量评论》2013,45(58):152-153
Abstract

In vol. iv, nos. 29 and 30, of the E.S.R., there appeared an article by Mr. D. R. Hendrikz on the “Adjustment of the Secondary Triangulation of South Africa”. He shows that, in applying the Schols method of orthomorphic transmission to the adjustment of a secondary net to a primary triangle, the secondary sides suffer small displacements.  相似文献   

17.
《测量评论》2013,45(29):430-437
Abstract

The Secondary Triangulation of South Africa consists of a uniform network of triangles of from 5- to 10-mile sides, enmeshed in the Geodetic and Primary Triangulations. As a rule the Primary Triangulation is rigorously adjusted by least squares, and the Secondary made to conform to it by an approximately rigorous method which was introduced into the Trigonometrical Survey in 1920 by the late Dr van der Sterr.  相似文献   

18.
Reducing the impact of the siricid wasp, Sirex noctilio is crucial for the future productivity and sustainability of commercial pine resources in South Africa. In this study we present a machine learning model that serves as a spatial guide and allows forest managers to focus their existing detection and monitoring efforts on key areas and proactively adopt the most appropriate course of intervention. We implemented the random forest model within a spatial framework to determine which pine forests in Mpumalanga are highly susceptible to S. noctilio infestations. Results indicate that a majority (63%) of pine forest plantations located in Mpumalanga have a high susceptibility (>70%) to S. noctilio infestation. A KHAT value of 0.84 and F measures above 0.87 indicate that the random forest model is a robust classifier that produces accurate results. Additionally, the use of the backward variable selection method enabled us to simplify the random forest modeling process and identify the minimum number of explanatory variables that offer the best discriminatory power and help in the empirical interpretation of the final random forest model. Overall, the results show that pine forests that experience stress caused by evapotranspiration and evaporation followed by rainfalls, especially during the summer months are more susceptible to S. noctilio infestations.  相似文献   

19.
ABSTRACT

City models have a wide variety of uses that require different kind of data representation or data models. Having a dynamic model that enables picking the right representations (meshes, volumetric data, point cloud, etc.) can prove useful to adapt an application to each user's needs. In this paper, we present an original method to create personalised visualisations of 3D city models on the fly. By organising the server data in a hierarchy of tiles, we are able to generate personalised models based on the user's preferences. These preferences take the shape of a set of rules that apply to each tile or city object and allow the user to choose which representation of the object to use depending on its position or semantic information (classification, height, etc.). Our method is designed around existing standards, guaranteeing the interoperability of the produced models.  相似文献   

20.
《测量评论》2013,45(2):84-86
Abstract

In 1924, when my application for a position in the Survey Department of North Borneo had been accepted, a surprisingly large number of my friends thought that my destination was somewhere in Africa or South or Central America. Of course everyone had heard of the “wild man of Borneo.” To be quite candid, my own knowledge was limited to the position of the island. As this. country seems to be so little known, a brief outline of its history and of the development of the Survey Department may be of interest.  相似文献   

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