With the rapid development of urbanization, the standard of living has improved, but changes to the city thermal environment have become more serious. Population urbanization is a driving force of residential expansion, which predominantly influences the land surface temperature (LST). We obtained the land covers and LST maps of Wuhan from Landsat-5 images in 2000, 2002, 2005, and 2009, and discussed the distribution of land use/cover change and LST variation, and we analyzed the correlation between population distribution and LST values in residential regions. The results indicated massive variation of land cover types, which was shown as a reduction in cultivatable land and the expansion of building regions. High-LST regions concentrated on the residential and industrial areas with low vegetation coverage. In the residential region, the population density (PD) had effects on the LST values. Although the area or variation of residential regions was close, lower PD was associated with lower mean LST or LST variation. Thus, decreasing the high-LST regions concentration by reducing the PD may alleviate the urban heat island effect on the residential area. Taken together, these results can provide supports for urban planning projects and studies on city ecological environments.
Geographic information portrayal standard within geographic information standards community in ISO 19117 is
consisted of symbol specification, symbol assignment, portrayal services, cartographic finishing rules and
implementation specification. The portrayal standard specifies a conceptual framework which includes classes,
attributes, associations and operations and is the base of implementation and sharing of the geographic information
portrayal. The portrayal standard associates geographic features with symbols. This paper starts up with the quantitative
methodology for specifying visual variables. Consequently, visual variable values of geographic information portrayal
are taken to be statistically analyzed on shape, size and color. Furthermore, a set of quantitative rules of visual variables
within the geographic information portrayal system are retrieved. Meanwhile, a visual variable model for portrayal is
founded in this paper. At last, the standard definition sharing of the portrayal is implemented with XML, which will
become model base of geographic information portrayal and visual analyses for earth observation data.
Knowledge sharing and semantic interoperability is a significant research theme in Geographical Information Science
(GIScience) because many researchers believe that semantic heterogeneity has been identified as the main obstacle for
GIScience development. Interoperability issues can exist at three levels: syntactic, structural (also called systemic) and
semantic. The former two, however, can be achieved by implementing international or domain standards proposed by
several organizations, for example, Open Geospatial Consortium (OGC), World Wide Web Consortium (W3C) and the
International Organization for Standardization/Technical Committee for Geographic information/Geomatics (ISO/TC
211). In this paper, we are concentrating on semantic interoperability, which is the sort of topic that halt conversations
and cause people's eyes to glaze over, from two aspects: data/information/knowledge and operation/processing. We
presented a service-centered architecture for semantic interoperability of geospatial data and processes. OGC standards
like Web Feature Service (WFS) and Web Map Service (WMS) have been employed as normative interfaces for
analyzing requests, division requests and delivering small requests. Ontology has been introduced to describe distributed
resource including various data and geo-processing operations. The role of interoperability, especially from semantic
perspective, has been distinguished at the first section in this paper. As a fundamental principal, the following section
introduces semantic web, web service and other related works at this orientation. We present our service-based
architecture in detail and its simple application at part three. Conclusion and further orientations have been illustrated at
Pedestrian are one main component in urban space, and it's they that influence and determine urban layout. Spatial
visibility analysis is a novel method in urban morphology and spatial configuration. Spatial visibility analysis in urban
morphology mainly studies on spatial features (street network for instance) in the city configuration and visibility with
humans in it. Through building the visibility of urban space, we can predict pedestrians flow movement trends to analyze
the spatial modes. We hypothesis individuals move on street network and change their ways of movement at road crosses
with viewshed directions. We can apply the isovist or viewshed to direct their behaviors, and we can analyze the
distribution of pedestrian flows potentially. In urban planning, the distribution of facility locations must be consistent
with pedestrian flows, and we can offer the estimate through the approach above. The paper first discusses the principle
of pedestrian behaviors based on viewshed and the concepts of visibility centricity, then quantifies the parameters of
visibility analysis on viewpoints to explore urban morphology of street network of WUHAN ZHONGNAN district. We
extract the viewpoints with higher value and draw their distribution map. At the same time we survey the pedestrian
facilities locations in city. This paper reveals the consistent relationship between them and demonstrates the influences of
geometric features on pedestrian facilities locations over metropolitan's areas based one visibility analysis.
Map presentation of geographical information based on GIS is an urgent problem lying in current GIS and cartography.
Handling of features' relationship is the key in automatic-mapping. However, the discover and disposal of spatial
conflict is the lowest degree of automation in cartography. A lot of work is still in handwork. After analyzing the data in
the scale of 1:50,000 and 1:250,000, this article summarizes the relationship of cartographic features as
overlapping-relation, attachment-relation and collision-relation. Combined with the data, the article put forward the
method which is related to each of relationship.
During the process of informatization, there produces a great deal of information resources. In order to manage these
information resources and use them to serve the management of business, government decision and public life, it is
necessary to establish a transparent and dynamic information resource catalog and its service system. This paper takes
the land-house management information resource for example. Aim at the characteristics of this kind of information, this
paper does classification, identification and description of land-house information in an uniform specification and
method, establishes land-house information resource catalog classification system&, metadata standard, identification
standard and land-house thematic thesaurus, and in the internet environment, user can search and get their interested
information conveniently. Moreover, under the network environment, to achieve speedy positioning, inquiring, exploring
and acquiring various types of land-house management information; and satisfy the needs of sharing, exchanging,
application and maintenance of land-house management information resources.
Cartographic visualization represents geographic information with a map form, which enables us retrieve useful
geospatial information. In digital environment, cartographic symbol library is the base of cartographic visualization and
is an essential component of Geographic Information System as well. Existing cartographic symbol libraries have two
flaws. One is the display quality and the other one is relations adjusting. Statistic data presented in this paper indicate
that the aliasing problem is a major factor on the symbol display quality on graphic display devices. So, effective graphic
anti-aliasing methods based on a new anti-aliasing algorithm are presented and encapsulated in an anti-aliasing graphic
library with the form of Component Object Model. Furthermore, cartographic visualization should represent feature
relation in the way of correctly adjusting symbol relations besides displaying an individual feature. But current
cartographic symbol libraries don't have this capability. This paper creates a cartographic symbol design model to
implement symbol relations adjusting. Consequently the cartographic symbol library based on this design model can
provide cartographic visualization with relations adjusting capability. The anti-aliasing graphic library and the
cartographic symbol library are sampled and the results prove that the two libraries both have better efficiency and effect.
Map projections are attempts to portray the surface of the earth or a portion of the earth onto a flat map surface. This can
not be done without any distortions of conformality, distance, direction, scale, and area. There are many map projections,
and each of them has its own set of advantages and disadvantages. The mapmaker must select the one best suited to their
application needs, reducing distortion of the most important features. However, how to select a 'proper' map projection
is a complex process involving general evaluation of map projection alternatives based on a set of characteristics that
describe these projections. And this process needs a systemic understanding of map projection, which usually can not be
achieved by end users. This paper introduced Expert system (ES) to solve this problem, and used Component Objects
Model (COM) technology to develop and interoperate the proposed system (developed with Visual Prolog 7.0 Personal
Edition®) with professional Geographical Information System (GIS) software. As an essential part of the article, the
authors also represented the knowledge, rules and reasoning methods of selecting an appropriate map projection as well.
Implementations and examples had been given to testify the feasibility.
Geostatistics analyst is based on the fundamental geographic principal, namely, things that are closer together tend to be
more alike than things that are farther apart and widely used in many fields. In this paper, taking Ganjiang Drainage as
sample region, we select IDW, Ordinary Kriging and Simple Kriging interpolation of geostatistics analyst to interpolate
rainfall data and use cross-validation to compare the results of interpolation. In order to find out the most suitable
interpolation method, we respectively use different interpolation methods with same parameters, same method with
different semivariogram model as well as considering trend influence and anisotropy to interpolate the rainfall data.
Comparing the results, we draw the following conclusions: (1) Under the premise of knowing mean, Simple Kriging
owns the highest interpolation precision. (2) Kriging has fine feature to reflect rainfall trend changing of larger-scale
extent. On the contrary, IDW can depict local detailed changing well. (3) Rainfall data exists weak autocorrelation. (4)
Exponential model of semivariogram has the highest precision than others. (5) Ignoring trend influence and anisotropy will not decrease the precision of interpolation.
Visibility analysis is an important aspect in terrain analysis. Terrain visibility calculation is a time-consuming process, and visibility algorithms are dedicated to reduce the algorithm complexity to enhance calculation speed. We use digital elevation model to represent terrain. This equal-distance discrete data structure can be processed by geometric algorithm. The paper judges line of sight (LOS) visibility through geometric vector cross product, then delivers an incremental method to calculate terrain visibility with comparison of elevation difference using increments base on grid size. We analyze the algorithm performance in two aspects: horizontal and vertical comparisons. Through vertical analysis, the run-time of the algorithms has been measured for different terrain configurations and different heights of the viewpoint in terrain region. The method is more simple, lower complexity and easier to realize. We give out many computational results of viewshed with different location, and analyze the their distribution characteristics. We conclude that this method have high efficiency in undulant terrain with long line of sight or deep valleys. Also we compare this method with ARCGIS viewshed function horizontally through many tests and find that incremental method is faster and finer than ARCGIS model.
As a process to find proper positions for annotations, annotation placing has been regarded as a difficult problem in
automatic map making. Following accepted cartographic conventions, the objective of a good label placement is to
display the geographic position of features with their corresponding text in a clear and harmonious fashion, and having
no overlap most important. In this paper, we think that annotation can have two categories by shape. The first is named
point locating annotation; the second is named line locating annotation. Both of them can be seen from a combinatorial
optimization point of view. Our research first evaluates the heuristic Tabu Search (TS), and then applies this method to
cartographic label placement. Lastly, based on an experiment made on 1/250000 topographic data of China, TS has
proven to be an efficient choice, with the best performance in quality. And results show that labels of cartographic
features almost have no overlap.
When GIS are constructed primarily for the inventory and analysis of geographic phenomena, the data requirements for
map production are often not considered. Such systems are also used to produce cartographic products including maps
and mapping datasets. However, existing mapping systems built on GIS databases fail to make high quality map, mainly
because most systems can not allow one to interactively change individual cartographic graphic representations to
protect geo-data from modifications. This paper presents an alternative approach that considers the map requirements
from the outset, then defines the unique characteristics and requirements for geo-cartography data to support a GIS-based
cartographic system, as well as the process models to create the maps. Any representation is free to be intervened,
and will not change geo-data. The geo-cartography data closes the relation between the geographic data and the
cartographic data, and performs the function of describing the GIS connection tables or expression rules in visualization
mechanism, and the function of supporting and saving the mapping edit in the map-making method. The cartographic
representation adopts the geo-cartography data having been edited, not the default cartographic symbols, thus carries out
map-making based on GIS, and is easy to renew maps.
By analyzing the specific requirement and practical procedure in digital cartography field, in this paper we put forward
an improved algorithm for buffer zone analysis and propose a method of applying the buffer zone analysis algorithm to
the process of conflict detecting and solving between spatial features. The principle of this method has been elaborated
and examples of its practical application in the cartographic system based on national basic geographic data at the scale
of 1: 250,000 have been presented. It is approved that this method is effective.