ABSTRACT To compare and evaluate the performance of different multi-GNSS fractional cycle biases (FCBs) products and precise point positioning (PPP) ambiguity resolution. We compare the stability and positioning performance of the School of Geodesy and Geomatics (SGG) and CNES GPS\Galileo FCBs products. The results show that similar stability and high consistency are observed between the two products

ABSTRACT Polyconic map projections are rarely used for world maps because traditional polyconic mappings do not have a favourable distortion pattern. However, this paper demonstrates that the generalized versions of these projections can be adjusted well for global maps. The formulae are optimized numerically to ensure that the projections will have as low distortion as possible. Furthermore, optimal

(2021). Editorial. Journal of Spatial Science: Vol. 66, No. 1, pp. 1-2.

(2021). AUTHOR AWARDS. Journal of Spatial Science: Vol. 66, No. 1, pp. 179-179.

ABSTRACT This study evaluated the use of low-cost materials for radiometric calibration of multispectral images. Four materials were tested: plywood panels painted with matte paint (M1); plywood panels covered with synthetic nappa leather (M2); Ethylene Vinyl Acetate (EVA) panels (M3), and plywood panels covered with Polyvinyl chloride (PVC) canvas (M4). The useful life of all materials and the errors

ABSTRACT GDOP minimization criterion is applied to optimize positioning configuration. In this study, two kinds of GDOPs are introduced, the first kind of GDOP does not consider the clock error, the second kind considers. Cone configuration with lowest GDOP is discussed and extended for Ultra-wideband positioning. For three-dimensional scenarios, the configuration sets with lowest GDOP can be obtained

ABSTRACT The phase difference method can compensate the atmospheric disturbance in GB-SAR interferometry without the process of phase unwrapping, but its accuracy and effectiveness have not been analysed. This paper, therefore, analyses and validates this method by a simulation experiment and two real data experiments. Furthermore, we establish a quadratic model of the phase difference method to deal

ABSTRACT Throughout the past few decades, advancements in global navigation satellite systems (GNSS), such as the Global Positioning System (GPS), have resulted in real-time planimetric accuracy at the centimetre level, whether achieved using Real-Time Kinematic (RTK) or Real-Time Network (RTN) approaches. This study examines and characterizes the performance of RTK and RTN solutions at three test

ABSTRACT This contribution is aimed to show that careful ionospheric modelling can enhance the single-frequency code single point positioning (SPP) performance for both kinematic and static scenarios. Attention is restricted to the SPP quality driven by the IRIM under geomagnetic storm conditions. A Kalman filter-based model is formed for kinematic/static SPP users with which one combines GPS single-frequency

ABSTRACT Remote sensing soil moisture (SM) has a low spatial resolution. By contrast, to validate remote SM maps, point measurements gathered from scattered in situ stations are typically used. Therefore, a single representative SM value for the entire domain is required. The simplest approach is the arithmetic mean. Here, eight upscaling methods for in situ SM based in geostatistical interpolations

The naïve algorithm for generating nearest-neighbour models determines the distance between every pair of nodes, resulting in quadratic running time. Such time complexity is common among spatial problems and impedes the generation of larger spatial models. In this article, an improved algorithm for the Mocnik model, an example of nearest-neighbour models, is introduced. Instead of solving k nearest-neighbour

(2020). Editorial. Journal of Spatial Science: Vol. 65, No. 3, pp. 375-376.

(2020). Best Research Paper Award 2020. Journal of Spatial Science: Vol. 65, No. 3, pp. 553-554.

Spatial trajectory data, interestingly attracting organizations to obtain mobility-based activity patterns of smartphone users. One of the basic objective in this regard is the determination of ‘stops’ or technically high-density points in the trajectory data. Most works carried out in this area uses variants of density-based clustering algorithms for determining stop points. One of the notable challenges

The location of highway signs has a significant impact on timely route-finding and also on avoiding potential driver confusion. This paper proposes an approach based on three-dimensional spatial analysis to determine the best attributes for signs and traffic flow concerning the visibility of signs. The position, height and perceived area of signs; maximum speed limit; and size of cars were utilized

Recently, it has been shown how quaternion-based representation of a rotation matrix has advantages over conventional Eulerian representation in 3D similarity transformations. The iterative estimation procedure in similarity transformations based on quaternions results in translations and (scaled) quaternion elements. One needs, therefore, an additional procedure for evaluating the rest of the transformation

Mobile signaling data (MSD) have become important for studying the characteristics of transportation network structures and human socioeconomic activities. However, the conversion of MSD into datasets that are suitable for transportation network analyses remains challenging, because MSD cannot directly reflect the transportation flow patterns through global positional system (GPS) data. We proposed

Informative feature extraction from hyperspectral image (HSI) is the primary and most challenging task in the hyperspectral data processing. The rich source of HSI information provides effective ground cover analysis which requires high computational cost and, using the original, classification accuracy suffers from the curse of dimensionality. Therefore, feature reduction has been applied through

(2020). Editorial. Journal of Spatial Science: Vol. 65, No. 2, pp. 189-189.

(2020). Nexus of BIM and GIS: integrating building and geospatial data. Journal of Spatial Science: Vol. 65, No. 2, pp. 191-192.

(2020). Author awards. Journal of Spatial Science: Vol. 65, No. 2, pp. 361-361.

(2020). JOURNAL OF SPATIAL SCIENCE REVIEWERS – 2019. Journal of Spatial Science: Vol. 65, No. 2, pp. 363-374.

Regularization is often necessary in parameter estimation of spherical radial basis function (SRBF) based regional gravity modelling. In this work, a new regularization method, namely the L1-norm regularization, also called the least absolute shrinkage selection operator (Lasso), is employed. This is different from the commonly used L2-norm regularization, also called the Tikhonov regularization. The

Airborne vector gravimetric data have become increasingly available. A general band-limited horizontal boundary value problem using horizontal components of these vector gravimetric data is formulated and solved to compute regional geoid. The disturbing potential on the geoid is determined directly using the data in the air. This one-step approach is permitted by exploiting the following: 1) band-limited

ABSTRACT In this study, Spatial Multi-Criteria Evaluation and the least cost path analysis were applied to find the optimal by-pass road alignment in the Tlokweng Planning Area in Botswana. One-At-a-Time sensitivity analysis and the statistical test for zero proportion were used to investigate the robustness of the entire model. Four alternative by-pass roads were produced stressing economic, environmental

Atmospheric sensing by Global Navigation Satellite System (GNSS) signals has been exclusively studied for over two decades. This study derives the real-time Precipitable Water Vapour (PWV) by taking 1 month GNSS observation data from 11 stations. A Country-wide Pressure and Temperature (CPT) model is applied to precisely determine PWV from Zenith Tropospheric Delay (ZTD). It shows that the computed

ABSTRACT The international GNSS service (IGS) started publishing the precise ephemeris files in the form of the standard products #3, version C (the sp3c files) in which the GPS satellite orbits and clocks and their uncertainties were available since 2004. Incorporating these uncertainties into the GPS observation equations results in a better stochastic model of the processing system. The reality

Positioning integrity is essential in navigation. A novel approach is proposed for integrity monitoring that combines the Advanced Receiver Autonomous Integrity Monitoring (ARAIM) with Non-Line-of-Sight (NLOS) detection method using 3D city models to aid multi-constellation GNSS positioning in challenging urban scenarios. A demonstration of the proposed approach is performed with real data in an urban

Accurate spatial modelling of forest characteristics is one of the most important challenges in remote sensing applications. In this study, we compared the ability of Multiple Linear Regression (MLR), Geographically weighted regression (GWR), and Random Forest (RF) to estimate different forest attributes based on field sample data and Landsat 8 image. CA was modelled with the highest accuracy compared

In the article is presented a method for creating an interactive web map of the preindustrial state on the basis of analogue nineteenth-century maps of Upper Silesia (southern Poland). The main objective was to present a universal operation scheme that would allow one to transform old topographic maps into interactive web maps. The Leaflet library was use as a working environment for programming. The

This paper introduces Singapore Views as a novel 3D-4D interface to visualize large space-time datasets with applications in smart cities. The engine enables a combination of geographic information system, geo-located data with high-resolution 3D models and multimedia. Space-time datasets from Singapore’s National Science Experiment (NSE) 2016 are used to test the functionality of Singapore Views.

Automatic building rooftop extraction is of great importance to many applications including building reconstruction, solar energy supply, and disaster management. This study proposes a building rooftop extraction method using DSM data generated from aerial stereo images and vegetation cover vector data. The method consists of five steps: noise filtering, dilation reconstruction, vegetation and terrain

Point feature selection aims at preserving global patterns of point cluster during map scaling. This is an important technique for clear presentation of points in multi-scale maps. However, existing methods tend to include single point features ignoring the spatial interactions between two types of points. For example, based on the Input Sharing mechanism in agglomeration economics, different types

Populating and depopulating cities have some degree of underutilised land. The duration of vacancy, or length of time a property remains unused, more strongly influences urban decline than the amount of vacant land. Assessment of the duration of vacancy is seldom conducted, due to a lack of linking longitudinal data. This research creates and applies a Python script to track the duration of vacancy

February 1, 2017, EOP 14C04 aligned to the ITRF2014 was adopted by IERS. To assess the improvement of EOP 14C04, the differences between EOP 14C04 and EOP 08C04 are firstly analyzed. Then, the causes of the differences between the two solutions are examined. Finally, the differences are further assessed for their prediction performance using the LS+AR model. The results demonstrate that (1) there is

(2020). Author Awards. Journal of Spatial Science: Vol. 65, Multi-GNSS processing, positioning and applications, pp. 187-187.

(2020). Multi-GNSS processing, positioning and applications. Journal of Spatial Science: Vol. 65, Multi-GNSS processing, positioning and applications, pp. 3-5.

(2020). Editorial. Journal of Spatial Science: Vol. 65, Multi-GNSS processing, positioning and applications, pp. 1-1.

(2020). Unmanned vehicle systems for geomatics: towards robotic mapping. Journal of Spatial Science: Vol. 65, Multi-GNSS processing, positioning and applications, pp. 185-186.

In this paper, a rank deficient adjustment model with inequality constrained is implemented to realise the conversion from the single-difference (SD) wide lane fractional cycle bias (WL-FCB) to undifferenced(UD) WL-FCB. The results are compared with the un-differential FCB published by Centre National d’Etudes Spatiales (CNES), and the temporal variation characteristics of SD WL-FCB and UD WL-FCB are

A modified algorithm combining equivalence theory with MPI technology to improve Global Navigation Satellite System data processing efficiency is presented. The reservation of covariance matrix, elimination of unknowns and parallelism of the equivalence algorithm are derived. Experimental results show that the algorithm can improve the efficiency of processing 100 IGS stations by 56% with negligible

We present the GLIMPSE system that provides a framework for storage, management, accessibility and integration of 3D LiDAR data acquired from multiple platforms. We detail a point cloud retrieval approach, which provides spatially optimised access to point cloud data from the system for a particular geographic area based on user specifications. We tested our point cloud retrieval approach to facilitate

In the paper, we derive Procrustes-based closed-form solutions to the point-wise weighted rigid-body transformation under different adjustment scenarios. We treat both asymmetric and symmetric cases. By asymmetric (or Gauss–Markov) models we mean those in which either a source system or a target system is subject to random errors. On the other hand, by the symmetric model (Gauss-Helmert or errors-in-variables)

Estimation of surface water quality parameters (SWQPs) from satellite imagery is a cost-effective method. Remote sensing algorithms are developed to map the relationship between satellite reflectance and concentrations of SWQPs. This study exploited principal component analysis (PCA) to decorrelate multispectral bands prior to developing algorithms for SWQPs. Landsat-8 surface reflectances are first

Digital building modelling faces issues related to inconsistent integration/interoperability, in particular for a BIM GIS convergence. A consistent data conversion approach should consider semantic and spatial geometric modelling, therefore potentially leading to a loss of spatial geometric information. This paper simplifies semantic solving, and concentrates on the accuracy of the spatial geometric

This study evaluates the feasibility of achieving improved positioning accuracy with raw GNSS measurements from recently released smartphones. Using Precise Point Positioning (PPP) as the processing mode, positioning accuracy of selected newly available devices are analyzed. These devices include Xiaomi Mi8, Google Pixel 3, Huawei Mate 20 and Samsung Galaxy S9. The key research questions to be answered

This paper conceptualises a future Spatial Knowledge Infrastructure (SKI), aparadigm shift from supplier-driven data and spatial analytics, to where end usersquery data at will to obtain new insights. The SKI addresses problems from theusers’ viewpoint, seeking real-time answers for informed decision making, ratherthan from a data producer’s perspective. The driving motivation, to satisfy society’sgrowing

Space-Filling Curves (SFCs) map a multi-dimensional cellular space into one dimension. Although several algorithms have been introduced that can generate different SFCs, they barely consider deploying SFCs for non-cellular spaces. This article presents a new higher-order functional approach that enables a new level of abstraction which separates the SFC representation (i.e. a set of functions that

In this study, the first results of the next-generation dual-frequency multi-constellation SBAS-based kinematic positioning in Australian urban environments are presented and analysed. As the standalone GNSS positioning is unable to deliver the accuracy required for absolute positioning in Intelligent Transport Systems (ITS), more advanced technologies are needed, and the Australian SBAS with PPP capabilities

In this contribution, we present the triple frequency long baseline RTK algorithm and assess the contribution of QZSS to multi-GNSS RTK. The impacts of multi-GNSS broadcast orbit errors, ionosphere, and troposphere errors on the long baseline RTK are analyzed. To assess the contribution of QZSS, multi-GNSS data are collected in Japan. The analysis of the results demonstrates that with the introduction

The authors investigate the benefits for the precise point positioning (PPP) ambiguity resolution technique of using the GPS L1, L2 and L5; Galileo E1, E5a, E5b and E6; and BeiDou B1, B2 and B3 measurements. Data from 17 reference stations over a period of 31 consecutive days in 2018 were used. It was found that the four-frequency Galileo combination of E1+E5a+E5b+E6 provides the lowest geometric and

In this study, an approach based on precise point positioning (PPP) is proposed for the assessment of global ionospheric maps (GIMs). This assessment is performed by comparing GIMs with vertical total electron content (VTEC) values retrieved using the PPP technique. The results indicate that the CODG, ESAG, WHUG, and CASG ionospheric products underestimate the VTEC values. There is a high level of

Coordinate transformation is indispensable to unify the three-dimensional (3D) points between different coordinate systems. Traditional methods are generally two-step work: transformation parameter estimation and coordinate transformation. Unlike traditional methods, this paper proposes a direct 3D coordinate transformation method based on the affine invariance of barycentric coordinates. The proposed

Municipalities are typically responsible for maintaining address data. Building and maintaining regional or national datasets from local sources requires careful coordination among stakeholders. The Centraal ReferentieadressenBestand (CRAB) is a digital authoritative address dataset, also referred to as a register, for the Flemish Region in Belgium. We present an analysis of the influence of CRAB stakeholders

Through an unmanned vehicle payload calibration campaign experiments, both reflectance-based and irradiance-based methods are used to calibrate multispectral sensor. The results show that both methods achieved good linear relationships between the digital numbers and apparent radiances (R2 > 0.99). Validation results demonstrated the relative error between the radiometric calibration and radiative

(2019). Editorial. Journal of Spatial Science: Vol. 64, No. 3, pp. 361-362.

(2019). Author Awards. Journal of Spatial Science: Vol. 64, No. 3, pp. 551-551.

(2019). Best Research and Review Paper Award 2019. Journal of Spatial Science: Vol. 64, No. 3, pp. 553-555.

(2019). Journal of Spatial Science Reviewers - 2018. Journal of Spatial Science: Vol. 64, No. 3, pp. 557-561.

ABSTRACT Reproducibility is widely regarded as crucial for scientific studies, yet there is still a lack of reproducibility in geospatial research. New sources of crowdsourced geoinformation provide new opportunities, but also complicate the reproducibility situation. Consequently, there is untapped potential in the domain of disaster response to reuse scientific methodology. Shared, executable scientific