共查询到20条相似文献，搜索用时 156 毫秒
1.
《The Cartographic journal》2013,50(3):257-261
Abstracttitle/>Patterns consisting of point symbols are commonly applied to symbolize land cover. Tree symbols, for example, indicate forested areas; small irregular dots show quarries and pits; or regular line symbols represent a vineyard. This paper presents an automatic method for synthesizing patterns consisting of one or more point symbols. Symbols of varying sizes or graphical appearance can be combined according to user-defined ratios. The automatic method generates patterns of regularly or irregularly distributed symbols. It ensures that symbols do not overlap and do not graphically conflict with other map features. The method has been implemented in a free plug-in for the Adobe Illustrator vector graphics editor. 相似文献
2.
Bernhard Jenny 《制图学和地理信息科学》2021,48(1):78-92
ABSTRACT Line integral convolution is a technique originally developed for visualizing vector fields, such as wind or water directions, that places densely packed lines following the direction of movement. Geisthövel and Hurni adapted line integral convolution to terrain generalization in 2018. Their method successfully removes details and retains sharp mountain ridges; it is particularly suited for creating generalized shaded relief. This paper extends line integral convolution generalization with a series of enhancements to reduce spurious artifacts, accentuate mountain ridges, control the level of detail in mountain slopes, and preserve sharp transitions to flat areas. The enhanced line integral convolution generalization effectively removes excessive terrain details without changing the position of terrain features. Sharp mountain ridgelines are accentuated, and transitions to flat waterbodies and valley bottoms are preserved. Shaded relief imagery derived from generalized elevation models is visually pleasing and resembles manually produced shaded relief. 相似文献
3.
《International Journal of Digital Earth》2013,6(2):121-138
ABSTRACTRural geotourism looks at the natural resources of the territory as a means of promoting a specialized, educational, sustainable tourism. This is an increasingly sought-after activity. This paper presents a rural georoute across a high mountain village, highlighting the remarkable value of the geological heritage of biological trace fossils and physical sedimentary structures exposed on street pavements and façades of houses. A series of tourist georesources were created and implemented: educational and interpretive panels, videos, QR codes, geoapps and games, all of which promote and disseminate the exceptional geological content and the history of the earth through the use of new technologies (smartphones, ipod, etc.). All this is intended as a means to make geotourism a natural tourism, favoring experiences, whilst explaining the natural environment and its temporal and spatial dimensions, offering opportunities for socio-economic development and job creation in rural areas with problems of depopulation. 相似文献
4.
《测量评论》2013,45(75):202-206
AbstractThe Cape Bar A has two sets of end marks. One set is represented by small dots in embedded surfaces of gold, and the other by finely engraved lines near the dots. The distance between the dots was measured in British units by Sir George Airy in 1839, and at the Ordnance Survey in. 1844; and the lines were standardised in international metres by M. Benoit at Paris in 1886. By lueasuring the small distances between the dots and the lines, and using the data of the original standardisations, it has been possible to obtain a value of the metre-foot relation. The ratio thus obtained agrees with the determinations of Benoit (1896) and Sears (1928). 相似文献
5.
J. C. T. W. 《测量评论》2013,45(18):254-255
AbstractAn officer ordered his native headman to go with his party to a distant mountain, arranged a rendezvous there with him on a certain date, and concluded his instructions by saying, ‘I shall expect to find a good-sized cairn on the top when I get there.’ Subsequently the encounter on the mountain-top took place. No cairn was visible, but the headman produced in its place a seedy-looking pi-dog with the remark, His mother was a cairn, but his father was too quick. 相似文献
6.
Abstract A community atlas is an effective method of promoting student‐centered, learning oriented instruction. It provides an integrated framework for teaching thematic interdisciplinary material and promotes collaborative work by students, whose efforts can be shared amongst themselves and with the community. This paper describes community atlas projects from three West Virginia middle schools, in which 320 students and five teachers participated. Younger and less structured students responded with more enthusiasm to the open‐ended nature of the assignment. Self‐disciplined students produced effective web pages combining images, maps, and non‐spatial information such as demographic tables and local perceptions. Although this project was a collaboration between a university and local middle schools, sufficient resources are available for teachers to implement community atlases without specialized assistance. 相似文献
7.
Abstract A linear regression‐based model for mapping forest age using Landsat Thematic Mapper data is evaluated in the lodgepole pine forests of Yellowstone National Park. Regression models predicting age (R2=0.62) and a logarithmic transformation of age (R2 = 0.90) used a combination of visible, near‐infrared, and middle‐infrared TM bands. Forest age maps produced using the regression method match broad‐scale patterns of forest age within the Yellowstone Central Plateau study area. Per‐pixel estimates of forest age, however, may depart substantially from actual forest age, particularly for older stands, and the maps are most appropriate for depicting regional patterns of forest age. 相似文献
8.
ABSTRACTDot maps have become a popular way to visualize discrete geographic data. Yet, beyond showing how the data are spatially distributed, dot maps are often visually cluttered in terms of consistency, overlap, and representativeness. Existing clutter reduction techniques like jittering, refinement, distortion, and aggregation also address this issue, but do so by arbitrarily displacing dots from their exact location, removing dots from the map, changing the spatial reference of the map, or reducing its level of detail, respectively. We present BinSq, a novel visualization technique to compare variations in dot density patterns without visual clutter. Based on a careful synthesis of existing clutter reduction techniques, BinSq reduces the wide variety of dot density variations on the map to a representative subset of density intervals that are more distinguishable. The subset is derived from a nested binning operation that introduces order and regularity to the map. Thereafter, a dot prioritization operation improves the representativeness of the map by equalizing visible data values to correspond with the actual data. In this paper, we describe the algorithmic implementation of BinSq, explore its parametric design space, and discuss its capabilities in comparison to six existing clutter reduction techniques for dot maps. 相似文献
9.
《The Cartographic journal》2013,50(1):7-17
AbstractJohn Keates is very well known for his numerous scholarly contributions to cartography as an academic discipline and science. However, throughout his career, he was also very actively involved in the design and production of maps. Mostly these were specialized thematic maps produced as the result of scientific research in the field sciences, especially in geology, glaciology and vegetation studies. However, during the 1970s he was much involved in the design and production of a considerable number of maps for recreation purposes, including maps for orienteering. Many of these maps were regarded at that time as being extremely innovative in terms of their cartographic design and layout. The article outlines the development of what became known as the 'Glasgow' style of map design John Keates' involvement with recreation maps in the 1970s. 相似文献
10.
《The Cartographic journal》2013,50(4):323-329
Abstracttitle/>Traffic delays can be used to quantify traffic congestion on the road. However, traffic delay data itself cannot provide readily useful content about congestion directly. The aim of this research is to develop a multi-scale visualisation of traffic delay (excess travel time in minutes per kilometre) derived from automatic number plate reading (ANPR) data, to enable traffic commuting patterns to and from Central London to be understood and analysed further. 相似文献
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12.
《The Cartographic journal》2013,50(4):291-296
AbstractManual shading, traditionally produced manually by specifically trained cartographers, is still considered superior to automatic methods, particularly for mountainous landscapes. However, manual shading is time-consuming and its results depend on the cartographer and as such difficult to replicate consistently. For this reason there is a need to create an automatic method to standardize its results. A crucial aspect of manual shading is the continuous change of light direction (azimuth) and angle (zenith) in order to better highlight discrete landforms. Automatic hillshading algorithms, widely available in many geographic information systems (GIS) applications, do not provide this feature. This may cause the resulting shaded relief to appear flat in some areas, particularly in areas where the light source is parallel to the mountain ridge. In this work we present a GIS tool to enhance the visual quality of hillshading. We developed a technique based on clustering aspect to provide a seamless change of lighting throughout the scene. We also provide tools to change the light zenith according to either elevation or slope. This way the cartographer has more room for customizing the shaded relief representation. Moreover, the method is completely automatic and this guarantees consistent and reproducible results. This method has been embedded into an ArcGIS toolbox. 相似文献
13.
《测量评论》2013,45(5):220-229
Abstract The Net.—The total length of the lines of the level-net is roughly 2400 miles. The net comprises 27 circuits with perimeters varying between 74 and 268 miles, and is generally closer in the wet zone than in the sparsely populated and undeveloped dry zones. In 12 circuits there are differences of level exceeding 1000 feet. The highest point reached in the net is 6572 feet, and a branch line runs from Nuwara Eliya to the summit of Pidurutalagala, the highest mountain in the island (8282 feet). 相似文献
14.
Abstract<title/>When the source data for the digital elevation model (DEM) are not known and any additional information or features such as skeleton lines of terrain is not available, a triangular regular network (TRN) is constructed with simple subdivision using one or two diagonals uniformly. Such a model gives inaccurate directions for interpolation because of the inaccurate diagonals used in triangulation and thereby, results in inaccurate contours representing artificial terrain features. In this study, a new method is developed based on slope information computed at DEM points determining accurate diagonals in the subdivision process, which is beneficial not only through the skeleton lines of a terrain but also all over the DEM. Consequently, it is shown that the proposed method is able to build a high fidelity TRN from a DEM without any additional information or features. 相似文献
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16.
ABSTRACT This paper addresses warm season hydroclimatic variability in the southern Appalachian region of the southeastern U.S., where precipitation can vary as much as 127?mm or more, with maximum seasonal totals exceeding 736?mm in extreme cases. Despite the occurrence of droughts, floods, and their socioecological impacts, hydroclimate variability is still poorly understood. This study characterizes the regional scale variations in the hydroclimate by examining the daily distribution of precipitation patterns in different topographic environments. Parameter-elevation relationships on independent slopes model (PRISM) gridded precipitation estimates are used to identify the location and frequency of different types of rainfall events. Several types of clustering algorithms are used as a regionalization approach to define areas where the precipitation regime exhibits similarities in its frequency of occurrence. The results are compared with internal validation statistics and a visualization is used to assess how well the resulting hydroclimatic regions align with different topographic environments. This study reveals the intricate spatial footprint of dry and wet regimes and demonstrates how clustering applications can be used with gridded climate data to determine where extremes are most likely to develop across mountain catchments. 相似文献
17.
《测量评论》2013,45(88):77-84
AbstractThis article discusses the observation equations which may be solved graphically by plotting position lines using the method of zenith distance intercepts, or solved analytically by the method of least squares.The general observation equation is modified for the particular case in which zenith distance is made equal to assumed co-latitude, thus simplifying the reduction of the observations.Adaptation of the theory to use with a theodolite is discussed together with the effects of sources of error and the methods which are proposed for their elimination.A routine of reduction is proposed and an example is given. 相似文献
18.
ABSTRACTIntersections are the critical parts where different traffic flows converge and change directions, forming “bottlenecks” and “clog points” in urban traffic. Intersection travel time is an important parameter for public route planning, traffic management, and engineering optimization. Based on low-frequency spatial-temporal Global Positioning System (GPS) trace data, this article presents a novel method for estimating intersection travel time. The proposed method first analyzes the different travel patterns of vehicles through an intersection, then determines the range of an intersection dynamically and reasonably, and obtains traffic flow speed and delay at the intersection under different travel patterns using a fuzzy fitting approach. Finally, the average intersection travel time is estimated from traffic flow speed and delay and intersection range in different travel patterns. Wuhan road network data and GPS trace data from taxicabs were tested in the experiments and the results show that the proposed method can improve the accuracy of travel time estimation at city intersections. 相似文献
19.
W. M. Gertsen 《The Cartographic journal》2013,50(2):113-118
AbstractThis paper describes the range of topographic maps produced by the Danish Geodetic Institute, some of the production methods together with plans for the future. 相似文献
20.
《International Journal of Digital Earth》2013,6(3):307-323
ABSTRACTForests of the Sierra Nevada (SN) mountain range are valuable natural heritages for the region and the country, and tree height is an important forest structure parameter for understanding the SN forest ecosystem. There is still a need in the accurate estimation of wall-to-wall SN tree height distribution at fine spatial resolution. In this study, we presented a method to map wall-to-wall forest tree height (defined as Lorey’s height) across the SN at 70-m resolution by fusing multi-source datasets, including over 1600 in situ tree height measurements and over 1600?km2 airborne light detection and ranging (LiDAR) data. Accurate tree height estimates within these airborne LiDAR boundaries were first computed based on in situ measurements, and then these airborne LiDAR-derived tree heights were used as reference data to estimate tree heights at Geoscience Laser Altimeter System (GLAS) footprints. Finally, the random forest algorithm was used to model the SN tree height from these GLAS tree heights, optical imagery, topographic data, and climate data. The results show that our fine-resolution SN tree height product has a good correspondence with field measurements. The coefficient of determination between them is 0.60, and the root-mean-squared error is 5.45?m. 相似文献