Automatic positional accuracy assessment of geospatial databases using line-based methods

Survey Review ◽  
2013 ◽  
Vol 45 (332) ◽  
pp. 332-342 ◽  
Author(s):  
J J Ruiz-Lendínez ◽  
F J Ariza-López ◽  
M A Ureña-Cámara
Keyword(s):  
Accuracy Assessment ◽  
Positional Accuracy ◽  
Geospatial Databases

scholarly journals Expert Knowledge as Basis for Assessing an Automatic Matching Procedure

2021 ◽  
Vol 10 (5) ◽  
pp. 289
Author(s):  
Juan José Ruiz-Lendínez ◽  
Francisco Javier Ariza-López ◽  
Manuel Antonio Ureña-Cámara
Keyword(s):  
Spatial Data ◽  
Expert Knowledge ◽  
Accuracy Assessment ◽  
Positional Accuracy ◽  
Human Capabilities ◽  
Operational Solution ◽  
Matching Procedure ◽  
Automatic Matching ◽  
Geospatial Databases ◽  
Very High

The continuous development of machine learning procedures and the development of new ways of mapping based on the integration of spatial data from heterogeneous sources have resulted in the automation of many processes associated with cartographic production such as positional accuracy assessment (PAA). The automation of the PAA of spatial data is based on automated matching procedures between corresponding spatial objects (usually building polygons) from two geospatial databases (GDB), which in turn are related to the quantification of the similarity between these objects. Therefore, assessing the capabilities of these automated matching procedures is key to making automation a fully operational solution in PAA processes. The present study has been developed in response to the need to explore the scope of these capabilities by means of a comparison with human capabilities. Thus, using a genetic algorithm (GA) and a group of human experts, two experiments have been carried out: (i) to compare the similarity values between building polygons assigned by both and (ii) to compare the matching procedure developed in both cases. The results obtained showed that the GA—experts agreement was very high, with a mean agreement percentage of 93.3% (for the experiment 1) and 98.8% (for the experiment 2). These results confirm the capability of the machine-based procedures, and specifically of GAs, to carry out matching tasks.

A point-based methodology for the automatic positional accuracy assessment of geospatial databases

Survey Review ◽  
2016 ◽  
Vol 48 (349) ◽  
pp. 269-277 ◽  
Author(s):  
J. J. Ruiz-Lendínez ◽  
F. J. Ariza-López ◽  
M. A. Ureña-Cámara
Keyword(s):  
Accuracy Assessment ◽  
Positional Accuracy ◽  
Geospatial Databases

scholarly journals DO OPEN GEODATA ACTUALLY HAVE THE QUALITY THEY DECLARE? THE CASE STUDY OF MILAN, ITALY

2016 ◽  
Vol XLI-B2 ◽  
pp. 609-614
Author(s):  
M. A. Brovelli ◽  
M. Minghini ◽  
M. E. Molinari ◽  
M. Molteni
Keyword(s):  
Spatial Data ◽  
Large Scale ◽  
Accuracy Assessment ◽  
Quality Parameters ◽  
Data Quality Control ◽  
Positional Accuracy ◽  
Systematic Assessment ◽  
Open Datasets ◽  
The Many

In the past number of years there has been an amazing flourishing of spatial data products released with open licenses. Researchers and professionals are extensively exploiting open geodata for many applications, which, in turn, include decision-making results and other (derived) geospatial datasets among their outputs. Despite the traditional availability of metadata, a question arises about the actual quality of open geodata, as their declared quality is typically given for granted without any systematic assessment. The present work investigates the case study of Milan Municipality (Northern Italy). A wide set of open geodata are available for this area which are released by national, regional and local authoritative entities. A comprehensive cataloguing operation is first performed, with 1061 geospatial open datasets from Italian providers found which highly differ in terms of license, format, scale, content, and release date. Among the many quality parameters for geospatial data, the work focuses on positional accuracy. An example of positional accuracy assessment is described for an openly-licensed orthophoto through comparison with the official, up-to-date, and large-scale vector cartography of Milan. The comparison is run according to the guidelines provided by ISO and shows that the positional accuracy declared by the orthophoto provider does not correspond to the reality. Similar results are found from analyses on other datasets (not presented here). Implications are twofold: raising the awareness on the risks of using open geodata by taking their quality for granted; and highlighting the need for open geodata providers to introduce or refine mechanisms for data quality control.

scholarly journals Accuracy Assessment of Duhok City Land use Official Maps

2019 ◽  
Vol 9 (2) ◽  
pp. 178-185
Author(s):  
Raad A. Kattan ◽  
Farsat H. Abdulrahman
Keyword(s):  
Accuracy Assessment ◽  
The Other ◽  
Global Coordinate System ◽  
Master Plan ◽  
Geometric Accuracy ◽  
Kurdistan Region ◽  
Positional Accuracy ◽  
Maximum Value ◽  
Reference Map ◽  
The Mean

In this study, the geometric accuracy of four different maps for three sectors of Duhok city was assessed. The maps were produced in different periods and different techniques. One set of maps was paper plotted maps, which had to be geo-referenced. The other three maps were digitally plotted with reference to the global coordinate system UTM/WGS-84/Zone 38 N projection. A total of 51 points were identified on one reference map, which is the master plan of Duhok city prepared by the general directorate of urban planning/Kurdistan region/Iraq with the collaboration of the German company Ingenieurburo Vossing Company. The reference map, which is the master plan of Duhok governorate, is an official map that is certified and checked by the ministry of planning of the Kurdistan region to have a positional accuracy of ±1.5 cm. These points were searched for and identified on the other three maps. Discrepancies in Easting and Northings of these points were calculated, which resulted in the mean discrepancy of 2.29 m with a maximum value of 8.5 m in one event. The maximum standard deviation in dE and dN was 3.8 m. These values are reasonably accepted, considering that the maps were prepared using different techniques and a variable accuracy standard.

scholarly journals Analysis of the Impact of Positional Accuracy When Using a Block of Pixels for Thematic Accuracy Assessment

Geographies ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 143-165
Author(s):  
Jianyu Gu ◽  
Russell G. Congalton
Keyword(s):  
Spatial Scale ◽  
Accuracy Assessment ◽  
Block Size ◽  
Positional Error ◽  
Positional Accuracy ◽  
Landscape Characteristics ◽  
Sensing Applications ◽  
Assessment Unit ◽  
Thematic Accuracy ◽  
The Impact

Pixels, blocks (i.e., grouping of pixels), and polygons are the fundamental choices for use as assessment units for validating per-pixel image classification. Previous research conducted by the authors of this paper focused on the analysis of the impact of positional accuracy when using a single pixel for thematic accuracy assessment. The research described here provided a similar analysis, but the blocks of contiguous pixels were chosen as the assessment unit for thematic validation. The goal of this analysis was to assess the impact of positional errors on the thematic assessment. Factors including the size of a block, labeling threshold, landscape characteristics, spatial scale, and classification schemes were also considered. The results demonstrated that using blocks as an assessment unit reduced the thematic errors caused by positional errors to under 10% for most global land-cover mapping projects and most remote-sensing applications achieving a half-pixel registration. The larger the block size, the more the positional error was reduced. However, there are practical limitations to the size of the block. More classes in a classification scheme and higher heterogeneity increased the positional effect. The choice of labeling threshold depends on the spatial scale and landscape characteristics to balance the number of abandoned units and positional impact. This research suggests using the block of pixels as an assessment unit in the thematic accuracy assessment in future applications.

scholarly journals MODIS Sensor Capability to Burned Area Mapping—Assessment of Performance and Improvements Provided by the Latest Standard Products in Boreal Regions

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5423
Author(s):  
José A. Moreno-Ruiz ◽  
José R. García-Lázaro ◽  
Manuel Arbelo ◽  
Manuel Cantón-Garbín
Keyword(s):  
Accuracy Assessment ◽  
Fire Service ◽  
Global Scale ◽  
Burned Area ◽  
Commission Error ◽  
Positional Accuracy ◽  
Wildfire Management ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

This paper presents an accuracy assessment of the main global scale Burned Area (BA) products, derived from daily images of the Moderate-Resolution Imaging Spectroradiometer (MODIS) Fire_CCI 5.1 and MCD64A1 C6, as well as the previous versions of both products (Fire_CCI 4.1 and MCD45A1 C5). The exercise was conducted on the boreal region of Alaska during the period 2000–2017. All the BA polygons registered by the Alaska Fire Service were used as reference data. Both new versions doubled the annual BA estimate compared to the previous versions (66% for Fire_CCI 5.1 versus 35% for v4.1, and 63% for MCD64A1 C6 versus 28% for C5), reducing the omission error (OE) by almost one half (39% versus 67% for Fire_CCI and 48% versus 74% for MCD) and slightly increasing the commission error (CE) (7.5% versus 7% for Fire_CCI and 18% versus 7% for MCD). The Fire_CCI 5.1 product (CE = 7.5%, OE = 39%) presented the best results in terms of positional accuracy with respect to MCD64A1 C6 (CE = 18%, OE = 48%). These results suggest that Fire_CCI 5.1 could be suitable for those users who employ BA standard products in geoinformatics analysis techniques for wildfire management, especially in Boreal regions. The Pareto boundary analysis, performed on an annual basis, showed that there is still a potential theoretical capacity to improve the MODIS sensor-based BA algorithms.

scholarly journals Study of NSSDA Variability by Means of Automatic Positional Accuracy Assessment Methods

2019 ◽  
Vol 8 (12) ◽  
pp. 552 ◽  
Author(s):  
Juan José Ruiz-Lendínez ◽  
Francisco Javier Ariza-López ◽  
Manuel Antonio Ureña-Cámara
Keyword(s):  
Theoretical Analysis ◽  
Sample Size ◽  
Spatial Data ◽  
Graphical Representation ◽  
Accuracy Assessment ◽  
Experimental Tests ◽  
National Standard ◽  
Positional Accuracy ◽  
Check Points ◽  
Spatial Dataset

Point-based standard methodologies (PBSM) suggest using ‘at least 20’ check points in order to assess the positional accuracy of a certain spatial dataset. However, the reason for decreasing the number of checkpoints to 20 is not elaborated upon in the original documents provided by the mapping agencies which develop these methodologies. By means of theoretical analysis and experimental tests, several authors and studies have demonstrated that this limited number of points is clearly insufficient. Using the point-based methodology for the automatic positional accuracy assessment of spatial data developed in our previous study Ruiz-Lendínez, et al (2017) and specifically, a subset of check points obtained from the application of this methodology to two urban spatial datasets, the variability of National Standard for Spatial Data Accuracy (NSSDA) estimations has been analyzed according to sample size. The results show that the variability of NSSDA estimations decreases when the number of check points increases, and also that these estimations have a tendency to underestimate accuracy. Finally, the graphical representation of the results can be employed in order to give some guidance on the recommended sample size when PBSMs are used.

scholarly journals COMPARISON BETWEEN ABSOLUTE AND RELATIVE POSITIONAL ACCURACY ASSESSMENT - A CASE STUDY APPLIED TO DIGITAL ELEVATION MODELS

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
Leandro Luiz Silva de França ◽  
Alex de Lima Teodoro da Penha ◽  
João Alberto Batista de Carvalho
Keyword(s):  
Thermal Emission ◽  
Accuracy Assessment ◽  
Digital Elevation Models ◽  
Shuttle Radar Topography Mission ◽  
Control Points ◽  
Positional Accuracy ◽  
Digital Elevation ◽  
The Absolute ◽  
Better Than

Abstract This paper presents a comparative study between the absolute and relative methods for altimetric positional accuracy of Digital Elevation Models (DEM). For the theoretical basis of this research, the definitions of accuracy (exactness) and precision, as well the concepts related to absolute and relative positional accuracy were explored. In the case study, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) DEM were used. In the analysis of the absolute accuracy, 6,568 ground control points from GNSS orbital survey were used, collected through relative-static method. In the relative accuracy, it was used as reference DEM with spatial resolution of 5 meters generated by stereophotogrammetrical process for the Mapping Project of Bahia (Brazil). It was concluded that, once the accuracy of the reference DEM is better than the other two evaluated DEM, the results of the classification for the PEC-PCD for the relative evaluation are equal to or better than the absolute evaluation results, with the advantage to being able to verify the pixel population of the evaluated models, which makes it possible to identify outliers, distortions and displacements, including delimiting regions, which is much less likely with a limited set of control points.

scholarly journals Automatic Positional Accuracy Assessment of Imagery Segmentation Processes: A Case Study

2021 ◽  
Vol 10 (7) ◽  
pp. 430
Author(s):  
Juan J. Ruiz-Lendínez ◽  
Manuel A. Ureña-Cámara ◽  
José L. Mesa-Mingorance ◽  
Francisco J. Quesada-Real
Keyword(s):  
High Resolution ◽  
Quality Assessment ◽  
Accuracy Assessment ◽  
Geographic Information ◽  
Aerial Image ◽  
Positional Accuracy ◽  
Key Aspects ◽  
Very High ◽  
The Ideal

There are many studies related to Imagery Segmentation (IS) in the field of Geographic Information (GI). However, none of them address the assessment of IS results from a positional perspective. In a field in which the positional aspect is critical, it seems reasonable to think that the quality associated with this aspect must be controlled. This paper presents an automatic positional accuracy assessment (PAA) method for assessing this quality component of the regions obtained by means of the application of a textural segmentation algorithm to a Very High Resolution (VHR) aerial image. This method is based on the comparison between the ideal segmentation and the computed segmentation by counting their differences. Therefore, it has the same conceptual principles as the automatic procedures used in the evaluation of the GI´s positional accuracy. As in any PAA method, there are two key aspects related to the sample that were addressed: (i) its size—specifically, its influence on the uncertainty of the estimated accuracy values—and (ii) its categorization. Although the results obtained must be taken with caution, they made it clear that automatic PAA procedures, which are mainly applied to carry out the positional quality assessment of cartography, are valid for assessing the positional accuracy reached using other types of processes. Such is the case of the IS process presented in this study.

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