共查询到20条相似文献，搜索用时 78 毫秒
1.
Geocoding has become a routine task for many research investigations to conduct spatial analysis. However, the output quality of geocoding systems is found to impact the conclusions of subsequent studies that employ this workflow. The published development of geocoding systems has been limited to the same set of interpolation methods and reference data sets for quite some time. We introduce a novel geocoding approach utilizing object detection on remotely sensed imagery based on a deep learning framework to generate rooftop geocoding output. This allows geocoding systems to use and output exact building locations without employing typical geocoding interpolation methods or being completely limited by the availability of reference data sets. The utility of the proposed approach is demonstrated over a sample of 22,481 addresses resulting in significant spatial error reduction and match rates comparable to typical geocoding methods. For different land‐use types, our approach performs better on low‐density residential and commercial addresses than on high‐density residential addresses. With appropriate model setup and training, the proposed approach can be extended to search different object locations and to generate new address and point‐of‐interest reference data sets. 相似文献
2.
Geocoding urban addresses usually requires the use of an underlying address database. Under the influence of the format defined for TIGER files decades ago, most address databases and street geocoding algorithms are organized around street centerlines, associating numbering ranges to thoroughfare segments between two street crossings. While this method has been successfully employed in the USA for a long time, its transposition to other countries may lead to increased errors. This article presents an evaluation of the centerline‐geocoding resources provided by Google Maps, as compared to the point‐geocoding method used in the city of Belo Horizonte, Brazil, which we took as a baseline. We generated a textual address for each point object found in the city's point‐based address database, and submitted it to the Google Maps geocoding API. We then compared the resulting coordinates with the ones recorded in Belo Horizonte's GIS. We demonstrate that the centerline segment interpolation method, employed by the online resources following the American practice, has problems that can considerably influence the quality of the geocoding outcome. Completeness and accuracy have been found to be irregular, especially within lower income areas. Such errors in online services can have a significant impact on geocoding efforts related to social applications, such as public health and education, since the online service can be faulty and error‐prone in the most socially demanding areas of the city. In the conclusion, we point out that a volunteered geographic information (VGI) approach can help with the enrichment and enhancement of current geocoding resources, and can possibly lead to their transformation into more reliable point‐based geocoding services. 相似文献
3.
Hassan A. Karimi Monir H. Sharker Duangduen Roongpiboonsopit 《Transactions in GIS》2011,15(6):869-886
Today, many services that can geocode addresses are available to domain scientists and researchers, software developers, and end‐users. For a number of reasons, including quality of reference database and interpolation technique, a given address geocoded by different services does not often result in the same location. Considering that there are many widely available and accessible geocoding services and that each geocoding service may utilize a different reference database and interpolation technique, selecting a suitable geocoding service that meets the requirements of any application or user is a challenging task. This is especially true for online geocoding services which are often used as black boxes and do not provide knowledge about the reference databases and the interpolation techniques they employ. In this article, we present a geocoding recommender algorithm that can recommend optimal online geocoding services by realizing the characteristics (positional accuracy and match rate) of the services and preferences of the user and/or their application. The algorithm is simulated and analyzed using six popular online geocoding services for different address types (agricultural, commercial, industrial, residential) and preferences (match rate, positional accuracy). 相似文献
4.
《International Journal of Digital Earth》2013,6(10):825-839
With the increased use of locational information, spatial location referencing and coding methods have become much more important to the mining of both geographical and nongeographical data in digital earth system. Unfortunately, current methods of geocoding, based on reverse lookup of coordinates for a given address, have proven too lossy with respect to administrative and socioeconomic data. This paper proposes a spatial subdivision and geocoding model based on spatial address regional tessellation (SART). Given a hierarchical address object definition, and based on the ‘region of influence’ characteristics of an address, SART creates multiresolution spatial subdivisions by irregular and continuous address regions. This model reflects most of the geographical features and many of the social and economic implications for a given address. It also better reflects the way people understand addresses and spatial locations. We also propose an appropriate method of geocoding for standard addresses (SART-GC). The codes generated by this method can record address footprints, hierarchical relationships, and spatial scales in a single data structure. Finally, by applying our methods to the Shibei District of Qingdao, we demonstrate the suitability of SART-GC for multi-scale spatial information representation in digital earth systems. 相似文献
5.
Daniel W. Goldberg 《Transactions in GIS》2011,15(6):829-850
Address ranges used in linear interpolation geocoding often have errors and omissions that result in input address numbers falling outside of known address ranges. Geocoding systems may match these input addresses to the closest available nearby address range and assign low confidence values (match scores) to increase match rates, but little is published describing the matching or scoring techniques used in these systems. This article sheds light on these practices by investigating the need for, technical approaches to, and utility of nearby matching methods used to increase match rates in geocode data. The scope of the problem is motivated by an analysis of a commonly used health dataset. The technical approach of a geocoding system that includes a nearby matching approach is described along with a method for scoring candidates based on spatially‐varying neighborhoods. This method, termed dynamic nearby reference feature scoring, identifies, scores, ranks, and returns the most probable candidate to which the input address feature belongs or is spatially near. This approach is evaluated against commercial systems to assess its effectiveness and resulting spatial accuracy. Results indicate this approach is viable for improving match rates while maintaining acceptable levels of spatial accuracy. 相似文献
6.
CATS: GPS coordinate time series analysis software 总被引：18，自引：4，他引：14
Simon D. P. Williams 《GPS Solutions》2008,12(2):147-153
Over the last 10 years, several papers have established that daily estimates of GPS coordinates are temporally correlated
and it is therefore incorrect to assume that the observations are independent when estimating parameters from them. A direct
consequence of this assumption is the over-optimistic estimation of the parameter uncertainties. Perhaps the perceived computational
burden or the lack of suitable software for time series analysis has resulted in many heuristic methods being proposed in
the scientific literature for estimating these uncertainties. We present a standalone C program, CATS, developed to study
and compare stochastic noise processes in continuous GPS coordinate time series and, as a consequence, assign realistic uncertainties
to parameters derived from them. The name originally stood for Create and Analyze Time Series. Although the name has survived,
the creation aspect of the software has, after several versions, been abandoned. The implementation of the method is briefly
described to aid understanding and an example of typical input, usage, output and the available stochastic noise models are
given. 相似文献
7.
Exposure to traffic‐related pollutants is associated with both morbidity and mortality. Because vehicle‐exhaust are highly localized, within a few hundred meters of heavily traveled roadways, highly accurate spatial data are critical in studies concerned with exposure to vehicle emissions. We compared the positional accuracy of a widely used U.S. Geological Survey (USGS) roadway network containing traffic activity data versus a global positioning system (GPS)‐validated road network without traffic information; developed a geographical information system (GIS)‐based methodology for producing improved roadway data associated with traffic activities; evaluated errors from geocoding processes; and used the CALINE4 dispersion model to demonstrate potential exposure misclassifications due to inaccurate roadway data or incorrectly geocoded addresses. The GIS‐based algorithm we developed was effective in transferring vehicle activity information from the less accurate USGS roadway network to a GPS‐accurate road network, with a match rate exceeding 95%. Large discrepancies, up to hundreds of meters, were found between the two roadway networks, with the GPS‐validated network having higher spatial accuracy. In addition, identifying and correcting errors associated with geocoding resulted in improved address matching. We demonstrated that discrepancies in roadway geometry and geocoding errors, can lead to serious exposure misclassifications, up to an order of magnitude in assigned pollutant concentrations. 相似文献
8.
9.
This survey article describes previous research addressing text‐based document geocoding, i.e. the task of predicting the geospatial coordinates of latitude and longitude, that best correspond to an entire document, based on its textual contents. We describe (1) early document geocoding systems that use heuristics over place names mentioned in the text (e.g. names of cities and states), (2) probabilistic language modeling approaches, where generative models are built for different regions in the world (usually considering a discretization based on a rectangular grid) from the words occurring in a set of georeferenced training documents, which are then used to predict per‐region probabilities for previously unseen test documents, (3) combinations of different models and heuristics, including clustering procedures, feature selection approaches, and/or language models built from different sources, and (4) recent approaches based on discriminative classification models. 相似文献
10.
Using the global positioning system (GPS) for people tracking continues to get easier. A person can transmit his/her GPS location from the carried mobile devices. The location is usually displayed as a dot on a digital map. However, a dot on the map is insufficient to reveal the person’s actual situation, e.g., an accident being happening. If the GPS is incorporated with an IP (Internet Protocol) camera, the camera image is critical in revealing the person’s actual situation and to improve the above-mentioned insufficient information. We present an approach to facilitate such incorporation. The approach consists of three phases: locating, tracking and monitoring collision. When the GPS coordinates of a person are within the field-of-view (FOV) of a camera, the approach enters the locating phase. The GPS coordinates are transformed to specify a candidate area (CA) in the image. The update of GPS coordinates is used to filter those moving objects within the CA until only one remains. After the person is located, he is being tracked using the shortest Euclidean distance method to find the most likely object in the next image. If the person collides with other objects while being tracked, a template matching technique, the sum of absolute difference (SAD), is used to locate the person in the collision area. The tracking is done after the person leaves the FOV of the camera. In the experimental studies, the tracking of one to three persons was performed using the implemented prototype. The average locating error of the tracking phase is only 5 pixels. The highest and average tracking success rates are 95.9% and 90.6%, respectively. These results show that the proposed approach is accurate and feasible for people tracking by incorporating GPS and IP cameras. 相似文献
11.
车载移动测图系统外方位元素标定方法 总被引：1，自引：1，他引：0
全景相机因其360°大视场、旋转不变性等优点,逐渐被用于构建车载移动测图系统。标定是保证系统获取精确地理信息数据的重要前提。本文针对全景相机和定位定姿系统(POS)集成的车载移动测图系统,提出一种外方位元素标定的方法。首先,在实际场景中布设高精度已知控制点。其次,构建全景球面模型,将全景影像通过球面投影反变换投影到该球面上,从球面上选择控制点而不是直接从存在扭曲的全景影像上选择控制点并得到其球面坐标。在建立点的相关性之后,结合地理参考绝对定位方程和坐标变换,求得全景相机相对POS的平移与旋转参数。最后,采用本文提出的标定方法,分别选择北京航天城和天津滨海新区进行试验。试验表明,GPS信号良好时,点的绝对定位中误差可达平面10.3cm、高程16.5cm;GPS信号不好时,点的绝对定位中误差为平面35.4cm、高程54.8cm;在较短距离范围内(3km),距离量测相对误差最大为5cm左右,GPS信号对相对量测没有明显影响。 相似文献
12.
Addressing location uncertainties in GPS‐based activity monitoring: A methodological framework 
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下载免费PDF全文 Location uncertainty has been a major barrier in information mining from location data. Although the development of electronic and telecommunication equipment has led to an increased amount and refined resolution of data about individuals’ spatio‐temporal trajectories, the potential of such data, especially in the context of environmental health studies, has not been fully realized due to the lack of methodology that addresses location uncertainties. This article describes a methodological framework for deriving information about people's continuous activities from individual‐collected Global Positioning System (GPS) data, which is vital for a variety of environmental health studies. This framework is composed of two major methods that address critical issues at different stages of GPS data processing: (1) a fuzzy classification method for distinguishing activity patterns; and (2) a scale‐adaptive method for refining activity locations and outdoor/indoor environments. Evaluation of this framework based on smartphone‐collected GPS data indicates that it is robust to location errors and is able to generate useful information about individuals’ life trajectories. 相似文献
13.
Positional Accuracy of Spatial Data: Non-Normal Distributions and a Critique of the National Standard for Spatial Data Accuracy 总被引：5，自引：0，他引：5
Paul A Zandbergen 《Transactions in GIS》2008,12(1):103-130
Spatial data quality is a paramount concern in all GIS applications. Existing spatial data accuracy standards, including the National Standard for Spatial Data Accuracy (NSSDA) used in the United States, commonly assume the positional error of spatial data is normally distributed. This research has characterized the distribution of the positional error in four types of spatial data: GPS locations, street geocoding, TIGER roads, and LIDAR elevation data. The positional error in GPS locations can be approximated with a Rayleigh distribution, the positional error in street geocoding and TIGER roads can be approximated with a log‐normal distribution, and the positional error in LIDAR elevation data can be approximated with a normal distribution of the original vertical error values after removal of a small number of outliers. For all four data types considered, however, these solutions are only approximations, and some evidence of non‐stationary behavior resulting in lack of normality was observed in all four datasets. Monte‐Carlo simulation of the robustness of accuracy statistics revealed that the conventional 100% Root Mean Square Error (RMSE) statistic is not reliable for non‐normal distributions. Some degree of data trimming is recommended through the use of 90% and 95% RMSE statistics. Percentiles, however, are not very robust as single positional accuracy statistics. The non‐normal distribution of positional errors in spatial data has implications for spatial data accuracy standards and error propagation modeling. Specific recommendations are formulated for revisions of the NSSDA. 相似文献
14.
GPS坐标转换方法对于GPS空间定位系统至关重要。目前已有很多方法被提出用于转换GPS坐标，但效果并不是很显著。究其原因，是因为大多数都存在模型误差和投影误差。针对目前方法的不足，本文利用深度学习对非结构化数据处理的优势，提出了一种基于卷积神经网络（CNN）的GPS坐标转换方法。该方法将GPS数据转化为非结构化图片数据，以其作为CNN的输入层来训练GPS坐标转换模型，这样能够最小化满足对数据的预处理要求，无监督地从数据中学习出有效特征。试验结果表明，该方法与传统坐标转换方法相比，具有更高的转换精度。 相似文献
15.
《制图学和地理信息科学》2013,40(4):301-318
The widespread use of Internet-based mapping and geospatial analysis has caused an increase in the demand for online geocoding services. Although such services provide convenience, low (or free) cost and immediate solutions, their characteristics, sometimes, overshadow the expectation of producing quality of geocoded results. In recent years, several geocoding techniques have emerged, including rooftop geocoding, but they have yet to receive much attention in the literature. This paper examines and compares the quality of online rooftop and street geocoding services based on match rates and positional accuracy. Six geocoding services by five providers (i.e., Microsoft Virtual Earth, Google, Geocoder.us, MapQuest, and Yahoo!) were evaluated using addresses in Allegheny County, Pennsylvania. Results of the comparison indicate that rooftop geocoding produces slightly lower match rates but significantly higher positional accuracy than street geocoding. The hybrid service, which combines the two techniques, produces match rates as high as other street geocoding services but improves in positional accuracy close to the level of rooftop geocoding. Geocoding services employing reference databases with similar quality trend to produce compatible match rates and positional accuracy. This paper examines the sensitivity of different address types on geocoding quality. The results reveal that both rooftop and street geocoding produce high match rates and high accuracy for residential addresses. However, positional accuracies of agricultural and industrial address types are not very reliable due to the small sample sizes. With these, it is recommended to use online rooftop geocoding services if high positional accuracy is the priority, use street geocoding if high match rate is the priority, and use the hybrid approach if both high match rates and high positional accuracy are required. 相似文献
16.
Geocoding systems typically use more than one geographic reference dataset to improve match rates and spatial accuracy, resulting in multiple candidate geocodes from which the single “best” result must be selected. Little scientific evidence exists for formalizing this selection process or comparing one strategy to another, leading to the approach used in existing systems which we term the hierarchy‐based criterion: place the available reference data layers into qualitative, static, and in many cases, arbitrary hierarchies and attempt a match in each layer, in order. The first non‐ambiguous match with suitable confidence is selected and returned as output. This approach assumes global relationships of relative accuracy between reference data layers, ignoring local variations that could be exploited to return more precise geocodes. We propose a formalization of the selection criteria and present three alternative strategies which we term the uncertainty‐, gravitationally‐, and topologically‐based strategies. The performance of each method is evaluated against two ground truth datasets of nationwide GPS points to determine any resulting spatial improvements. We find that any of the three new methods improves on current practice in the majority of cases. The gravitationally‐ and topologically‐based approaches offer improvement over a simple uncertainty‐based approach in cases with specific characteristics. 相似文献
17.
Using geographic information systems to link administrative databases with demographic, social, and environmental data allows researchers to use spatial approaches to explore relationships between exposures and health. Traditionally, spatial analysis in public health has focused on the county, ZIP code, or tract level because of limitations to geocoding at highly resolved scales. Using 2005 birth and death data from North Carolina, we examine our ability to geocode population‐level datasets at three spatial resolutions – zip code, street, and parcel. We achieve high geocoding rates at all three resolutions, with statewide street geocoding rates of 88.0% for births and 93.2% for deaths. We observe differences in geocoding rates across demographics and health outcomes, with lower geocoding rates in disadvantaged populations and the most dramatic differences occurring across the urban‐rural spectrum. Our results suggest that highly resolved spatial data architectures for population‐level datasets are viable through geocoding individual street addresses. We recommend routinely geocoding administrative datasets to the highest spatial resolution feasible, allowing public health researchers to choose the spatial resolution used in analysis based on an understanding of the spatial dimensions of the health outcomes and exposures being investigated. Such research, however, must acknowledge how disparate geocoding success across subpopulations may affect findings. 相似文献
18.
Classifying Human Activity Patterns from Smartphone Collected GPS data: A Fuzzy Classification and Aggregation Approach 下载免费PDF全文
下载免费PDF全文 Smartphones have emerged as a promising type of equipment for monitoring human activities in environmental health studies. However, degraded location accuracy and inconsistency of smartphone‐measured GPS data have limited its effectiveness for classifying human activity patterns. This study proposes a fuzzy classification scheme for differentiating human activity patterns from smartphone‐collected GPS data. Specifically, a fuzzy logic reasoning was adopted to overcome the influence of location uncertainty by estimating the probability of different activity types for single GPS points. Based on that approach, a segment aggregation method was developed to infer activity patterns, while adjusting for uncertainties of point attributes. Validations of the proposed methods were carried out based on a convenient sample of three subjects with different types of smartphones. The results indicate desirable accuracy (e.g. up to 96% in activity identification) using of this method. Two examples are provided in the Appendix to illustrate how the proposed methods could be applied in environmental health studies. Researchers could tailor this scheme to fit a variety of research topics. 相似文献
19.
Inferring the home locations of Twitter users based on the spatiotemporal clustering of Twitter data 下载免费PDF全文
下载免费PDF全文 Residential locations play an important role in understanding the form and function of urban systems. However, it is impossible to release this detailed information publicly, due to the issue of privacy. The rapid development of location‐based services and the prevalence of global position system (GPS)‐equipped devices provide an unprecedented opportunity to infer residential locations from user‐generated geographic information. This article compares different approaches for predicting Twitter users' home locations at a precise point level based on temporal and spatial features extracted from geo‐tagged tweets. Among the three deterministic approaches, the one that estimates the home location for each user by finding the weighted most frequently visited (WMFV) cluster of that user always provides the best performance when compared with the other two methods. The results of a fourth approach, based on the support vector machine (SVM), are severely affected by the threshold value for a cluster to be identified as the home. 相似文献
20.
为了使G PS 的观测成果在实际中得到更好的应用,必须把 G PS 观测得到的WGS-84坐标转换成实际需要的国家大地坐标或地方独立坐标。本文利用 Excel软件的宏程序VBA进行编程,实现不同坐标系之间坐标的相互转换。并且例举了坐标转换的算例,实验表明：所编程序可以快捷、准确、可靠地解决不同坐标间的转换问题,能够满足实际工作的需要。 相似文献