MAPGIS在国土资源大调查中的应用介绍

国土资源大调查离不开地理信息系统的应用,MAPGIS是科技部首推的国产地理信息系统软件,对MAPGIS功能的了解十分重要。本文对MAPGIS数字地图库、专业属性数据库的管理和GPS数据转换等方面的应用作了初步介绍,以使广大地质科技人员认识到MAPGIS在国土资源大调查中的重要作用。     

Addendum to: Strength of the Solar Coronal Magnetic Field – A Comparison of Independent Estimates Using Contemporaneous Radio and White-Light Observations

This addendum uses an alternate fit for the electron density distribution \(N(r)\) (see Figure 1) and estimates the coronal magnetic field using the new model. We find that the estimates of the magnetic field are in close agreement using both the models.

We have fit the \(N(r)\) distribution obtained from STEREO-A/COR1 and SOHO/LASCO-C2 using a fifth-order polynomial (see Figure 1). The expression can be written as

$$\begin{aligned} N_{\text{cor}}(r) &= 1.43 \times 10^{9} r^{-5} - 1.91 \times 10^{9} r^{-4} + 1.07 \times 10^{9} r^{-3} - 2.87 \times 10^{8} r^{-2} \\ &\quad {} + 3.76 \times 10^{7} r^{-1} - 1.91 \times 10^{6} , \end{aligned}$$

(1)

where \(N_{\text{cor}}(r)\) is in units of cm^?3 and \(r\) is in units of \(\mathrm{R}_{\odot}\). The background coronal electron density is enhanced by a factor of 5.5 at 2.63 \(\mathrm{R}_{\odot}\) during the coronal mass ejection (CME). The estimated coronal magnetic field strength (\(B\)) using radio data indicates that \(B(r) \approx(0.51\text{\,--\,}0.48) \pm 0.02\ \mathrm{G}\) in the range \(r \approx2.65\text{\, --\,}2.82\ \mathrm{R}_{\odot}\). The field strengths for STEREO-A/COR1 and SOHO/LASCO-C2 are ≈?0.32 G at \(r \approx 3.11\ \mathrm{R}_{\odot}\) and ≈?0.12 G at \(r \approx 4.40\ \mathrm{R}_{\odot}\), respectively.

     

Recommending attractive thematic regions by semantic community detection with multi-sourced VGI data

Attractive regions can be detected and recommended by investigating users’ online footprints. However, social media data suffers from short noisy text and lack of a-priori knowledge, impeding the usefulness of traditional semantic modelling methods. Another challenge is the need for an effective strategy for the selection/recommendation of candidate regions. To address these challenges, we propose a comprehensive workflow which combines semantic and location information of social media data to recommend thematic urban regions to users with specific interests. This workflow is novel in: (1) developing a data-driven geographic topic modelling method which utilizes the co-occurrence patterns of self-explanatory semantic information to detect semantic communities; (2) proposing a new recommendation strategy with the consideration of region’s spatial scale. The workflow was implemented using a real-world dataset and evaluation conducted at three different levels: semantic representativeness, topic identification and recommendation desirability. The evaluation showed that the semantic communities detected were internally consistent and externally differentiable and that the recommended regions had a high degree of desirability. The work has demonstrated the effectiveness of self-explanatory semantic information for geographic topic modelling and highlighted the importance of including region spatial scale into the model for an effective region recommending strategy.     

Cut slope stability evaluation of NH-21 along Nalayan-Gambhrola section, Bilaspur district, Himachal Pradesh, India

In the present work a ready reckon (a handbook used for computation/reference) model for the evaluation of slope instability of road sections, particularly in mountainous terrain, is presented. The integrated approach incorporates different aspects of physical and geotechnical parameters, structural kinematics and the role of different clay minerals constituting the slope-forming materials, aimed at deciphering and understanding the mechanisms that controlled the slope instability. The role of the major sets of discontinuities, derived from stereo plots of structural data, with regard to the total number of unstable slopes present in each segment was considered, and the critical section was determined. The intense monsoon season rainfall in the area not only contributed to weathering of the rock mass, but also increased the water content in the clays that were present, leading to a reduction in the stability of natural slopes. The study revealed that where the slopes displayed relative presence of montmorillonite clays, with significant swelling capacity, failures were more frequent.     

Palynological evidence for the Palaeocene evolution of the forearc basin, Indus Suture Zone, Ladakh, India

The discovery of Permian, Mesozoic and Palaeocene palynomorphs from the Nindam forearc basin, exposed along the Indus Suture Zone in Ladakh, is reported. The palynomorphs are from volcanogenic sandstones and are poorly preserved, distorted and show the effects of abrasion (striation marks). The frequent occurrence of Proxapertites indicates the assemblage is at least Palaeocene in age. The Palaeocene palynomorphs and sediments were transported to the Nindam trough from nearby elevated landward regions (islands). These Palaeocene provenance areas were characterized by an estuarine, nearshore, tropical, warm‐humid environment and were situated at equatorial palaeolatitudes. However, the occurrence of Permian and Mesozoic palynomorphs in the assemblage indicates that the Late Palaeozoic and Mesozoic Tethyan sedimentary rocks exposed along the northern margin of the Indian plate were redeposited into the tectonically active Cretaceous–Palaeocene trench–subduction complex that existed between the Indian and the Asian plates until the collision took place at ～50–60 Ma.     

New class of regular and well behaved exact solutions in general relativity

We present a new class of spherically symmetric regular and well behaved solutions of the general relativistic field equations in isotropic coordinates. These solutions describe perfect fluid balls with positively finite central pressure and positively finite central density; their ratio is less than one and causality condition is obeyed at the centre. The solutions of this class, the outmarch of pressure, density pressure-density ratio and the ratio of sound speed to light is monotonically decreasing. Keeping in view of well behaved nature in terms of central red shift and surface red shift and by assuming the surface density ρ _b =2×10¹⁴ g/cm³, we constructed a Neutral star model for k=2, resulting into maximum mass ≈6.36M _Θ, linear dimension ≈48.08 km, surface red shift ≈1.132 and central red shift ≈17.1314.     

Political economy of population growth

Tracing the origin of political economy as a class-science, this paper focuses on the political economy of population growth. Exposing the limitations of Malthusian ideas and their invalidity even for the capitalist economies, it discusses the subsequent revival of the Malthusian model during the period of de-colonization and the misinterpretation of the relationship between population growth and development in the developing and developed countries. Taking India, China, and Japan as some case studies, the paper examines the relationship between birth rate levels and some correlates. It elaborates on the Indian experience, emphasizing the association of population growth with poverty and unemployment and lays bare some of the hidden causes of these phenomena. The authors examine some interstate variations in India and identify constraints and prospects of the existing population policy. The paper proposes outlines of a democratic population policy as an integral part of India's development strategy which should recognize human beings not simply as consumers but also as producers of material values. It pleads for 1) restructuring of property relations; 2) bringing down the mortality rates and raising of the literacy levels, especially among females; and 3) improving nutritional levels, as prerequisites for bringing down birth rates.     

Population and development linkages: perspectives and research tasks

The author argues that the linkages between population and development are too complex to be understood in a narrow cause-effect frame. It is suggested that population policies designed to lower birth rates have succeeded only where certain prerequisites could be created. Focussing upon some of the popular perspectives, the author's study indicates research tasks and questions which, if pursued seriously, can help in comprehending the multidimensionality of population-development relationships. Sections discuss perspectives; a dichotomous world scenario with regard to population growth and development; the myth and reality in the mismatch between world population growth and potential resources in the context of technological developments; status, gaps, and tasks in population research in geography; population growth; determinants of population growth; and literacy and education.