Publikační činnost Katedry geoinformatiky / Publications of Department of Geographic Information Systems (548)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64770

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry geoinformatiky (548) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 76 results

Small-scale regional engineering geological study of the Czech Republic evaluating the relationship between slope gradients and engineering geological zones
(Springer Nature, 2024) Marschalko, Marian; Zięba, Zofia; Růžičková, Kateřina; Růžička, Jan; Kubáč, Jan; Dąbrowska, Jolanta; Sysala, David; Krčmář, David
The aim of the small-scale regional engineering geological study of the Czech Republic was to evaluate the relationship between slope gradient and engineering geological zones. The research motivation was to determine the average slope gradient, 25%, 50% (median) and 75% quantiles related to the different engineering geological zones. This scientific information is critical from the perspectives of engineering geology, geotechnical engineering, and foundation engineering because an increasing slope gradient evokes the need to create a cut respectively foundation excavation or another excavation in the geological structure, which increases the probability of occurrence of the problem in terms of differential settlement and bearing capacity of the structures. The research was carried out in the territory of the Czech Republic in 8 Quaternary zones with soil foundation ground and 10 pre-Quaternary zones with rocks and semi-rocks and their eluvia. A significant difference in the statistical characteristics of slope gradients was found in the group of Quaternary engineering geological zones (evaluated group I) compared to the group of pre-Quaternary zones (evaluated group II). The value range of the average slope gradient was 1.65 degrees (16.9%) to 5.89 degrees (60.3%) for the Quaternary engineering geological zones (soil foundation ground), representing 43.4% difference. Whereas for the over-quaternary engineering geological zones (rocks, semi-rocks and their eluvia), the difference was much higher, 3.59 degrees (36.8%) to 9.76 degrees (100%-value determined as a referential because it was the maximum), which is also reflected in a more significant percentage difference of 63.2%.
Automatic sketch map creation from labeled planar graph
(Taylor & Francis, 2024) Rapant, Petr; Menšík, Marek; Albert, Adam
Maps constructed in Euclidean space are commonly used to visuallypresent information about the real world. However, their creation isresource intensive, be it financial, technical, human, or time-con-suming, which can limit their timeliness and detail. A simpler formof visualization of data about the real world is represented bysketch maps, which mainly capture the topology and mutual fea-tures’ spatial location. By default, they are drawn by hand. This pre-supposes that the creator has a good knowledge of the depictedterritory, can create a cognitive map, and is skilled in transformingit into a graphical form. Sketch maps can be detailed and up-to-date if these prerequisites are met. Our question was whether it ispossible to meet these assumptions in another way: acquire know-ledge of the territory by processing narratives related to the area ofinterest, create a suitable computer representation for further proc-essing, and automatically generate the resulting sketch map. Thisarticle presents the last step – creating a sketch map based on spa-tial data acquired from narratives. The results show that even with-out metric data, it is possible to automatically generate a sketchmap visually close to the actual situation.
Thermodynamic theory of the most energy-efficient natural repose angle
(Springer Nature, 2023) Zegzulka, Jiří; Maršík, František; Nečas, Jan; Hlosta, Jakub; Žurovec, David; Ivan, Igor
This paper describes the formation of the natural repose angle of non-cohesive bulk materials. The repose angle of particulates alpha is the angle between the tangent plane to the surface of the slope and the solid base. The paper presents a thermodynamic theory for the formation of the most energy-efficient natural slope alpha asymptotic to 30 degrees that can be found very often both in nature and industry. The theoretical foundation is based on Janssen theory of the statistical distribution of vertical and horizontal stress and adds its own consideration about dissipative work during the movement of material as a slope is being formed. The presented model is expanded to include an experimental part describing four methods of creation of a natural repose angle on three sand samples. The experiments performed demonstrated the validity of the submitted theory and the thermodynamic model with certain deviations derived from the essence of the experiments performed. These experiments explain a frequent occurrence of natural slopes with a repose angle of around 30 degrees.
Spatiotemporal visualisation of PS InSAR generated space–time series describing large areal land deformations using diagram map with spiral graph
(MDPI, 2022) Struhár, Juraj; Rapant, Petr
The space–time series carry information on temporal and spatial patterns in observed phenomena. The reported research integrates computational, visual and cartographic methods to support visual analysis of space–time series describing terrain surface movement. The proposed methodology for space–time series visualisation can support their analysts in investigating space– time patterns using transformation, clustering, filtration and visualisation. The presented approach involves spiral graphs for representation time dimension and cartographic visualisation through proportional point symbol map for representation of spatial dimension. The result is an intuitive visualisation of space–time series, conveying the sought-after spatio-temporal information. For practical tests, we used space–time series obtained by permanent scatterers interferometry (PS InSAR) to monitor the Earth’s surface movement above the underground gas storage (UGS) Tvrdonice, the Czech Republic. An UGS is characterised by periodic injection and withdrawal of natural gas, which induces periodic movement of the terrain above it. We have verified that our visualisation method provides the required pattern information and is easy to use.
Monitoring non-linear ground motion above underground gas storage using GNSS and PSInSAR based on Sentinel-1 data
(MDPI, 2022) Struhár, Juraj; Rapant, Petr; Kačmařík, Michal; Hlaváčová, Ivana; Lazecký, Milan
Several methods allow accurate measurement of terrain surface motions. Global navigation satellite systems (GNSSes) and interferometry with synthetic aperture radar (InSAR) stand out in terms of measurement accuracy among them. In principle, both methods make it possible to evaluate a three-dimensional vector of the motion of points on the terrain surface. In this work, we dealt with the evaluation of motions in the up-down (U-D) and east-west direction (E-W) over underground gas storage (UGS) from InSAR. One crucial step in breaking down PSInSAR line of sight (LOS) measurements to U-D and E-W components is getting time series derived from individual tracks to the same time frame. This is usually performed by interpolation, but we used an innovative approach: we analyzed individual time series using the Lomb-Scargle periodogram (LSP), which is suitable for periodic noisy and irregularly sampled data; we selected the most significant period, created LSP models, and used them instead of the original time series. Then, it was possible to derive time series values for any arbitrary time step. To validate the results, we installed one GNSS receiver in the Tvrdonice UGS test area to perform independent measurements. The results show a good agreement in the evaluation of motions by both methods. The correlation coefficient between horizontal components from both PSInSAR and GNSS was 0.95 in the case of the E-W component, with an RMSE of 1.75 mm; for U-D they were 0.78 and 2.35 mm, respectively. In addition to comparing the motions in the U-D and E-W directions, we also created a comparison by converting GNSS measurements to a line of sight of the Sentinel-1 satellite to evaluate the conformity of InSAR and GNSS measurements. Based on descending track, the correlation coefficient between LOS from both methods is, on average, 0.97, with an RMSE of 2.70 mm.
Vehicle detection using panchromatic high-resolution satellite images as a support for urban planning. Case study of Prague's centre
(Sciendo, 2022) Golej, Peter; Horák, Jiří; Kukuliač, Pavel; Orlíková, Lucie
The optical sensors on satellites nowadays provide images covering large areas with a resolution better than 1 meter and with a frequency of more than once a week. This opens up new opportunities to utilize satellite-based information such as periodic monitoring of transport flows and parked vehicles for better transport, urban planning and decision making. Current vehicle detection methods face issues in selection of training data, utilization of augmented data, multivariate classification or complexity of the hardware. The pilot area is located in Prague in the surroundings of the Old Town Square. The WorldView3 panchromatic image with the best available spatial resolution was processed in ENVI, CATALYST Pro and ArcGIS Pro using SVM, KNN, PCA, RT and Faster R-CNN methods. Vehicle detection was relatively successful, above all in open public places with neither shade nor vegetation. The best overall performance was provided by SVM in ENVI, for which the achieved F1 score was 74%. The PCA method provided the worst results with an F1 score of 33%. The other methods achieved F1 scores ranging from 61 to 68%. Although vehicle detection using artificial intelligence on panchromatic images is more challenging than on multispectral images, it shows promising results. The following findings contribute to better design of object-based detection of vehicles in an urban environment and applications of data augmentation.
Public transport tweets in London, Madrid and Prague in the COVID-19 period-temporal and spatial differences in activity topics
(MDPI, 2022) Zajac, Martin; Horák, Jiří; Osorio-Arjona, Joaquín; Kukuliač, Pavel; Haworth, James
Public transport requires constant feedback to improve and satisfy daily users. Twitter offers monitoring of user messages, discussion and emoticons addressed to official transport provider accounts. This information can be particularly useful in delicate situations such as management of transit operations during the COVID-19 pandemic. The behaviour of Twitter users in Madrid, London and Prague is analysed with the goal of recognising similar patterns and detecting differences in traffic related topics and temporal cycles. Topics in transit tweets were identified using the bag of words approach and pre-processing in R. COVID-19 is a dominant topic for both London and Madrid but a minor one for Prague, where Twitter serves mainly to deliver messages from politicians and stakeholders. COVID-19 interferes with the meaning of other topics, such as overcrowding or staff. Additionally, specific topics were discovered, such as air quality in Victoria Station, London, or racism in Madrid. For all cities, transit-related tweeting activity declines over weekends. However, London shows much less decline than Prague or Madrid. Weekday daily rhythms show major tweeting activity during the morning in all cities but with different start times. The spatial distribution of tweets for the busiest stations shows that the best-balanced tweeting activity is found in Madrid metro stations.
Multi-GNSS positioning for landslide monitoring: A case study at the Recica landslide
(Akademie věd České republiky, Ústav struktury a mechaniky hornin, 2022) Li, Weiguo; Kačmařík, Michal; Pospíšil, Pavel
Global Navigation Satellite System (GNSS) positioning has characteristics of simple operation, high efficiency and high precision technique for landslide surface monitoring. In recent years, finalization of modern GNSS systems Galileo and BeiDou has brought a possibility of multi-GNSS positioning. The paper focuses on evaluation of possible benefits of multi-GNSS constellations in landslide monitoring. While simulating observational conditions of selected Recica landslide in the Czech Republic, one-month data from well-established permanent GNSS reference stations were processed. Besides various constellation combinations, differential and Precise Point Positioning techniques, observation data lengths and observation sampling intervals were evaluated. Based on the results, using a combination of GPS and GLONASS, or GPS, GLONASS and Galileo systems can be recommended, together with a static differential technique and observation periods for data collection exceeding eight hours. In the last step, data from GNSS repetitive campaigns realized at the Recica landslide during two years were processed with optimal setup and obtained displacement results were compared to standard geotechnical measurements.
The importance of mobility for the autonomy of seniors
(Jihočeská univerzita v Českých Budějovicích, Zdravotně sociální fakulta, 2022) Joukl, Miroslav; Vítková, Lucie; Truhlářová, Zuzana; Marešová, Petra; Orlíková, Lucie
Spatial mobility of seniors is one of the current topics under investigation. Its relevance is due to both the ageing population and issues related to the quality of life of seniors. It is linked to how the spatial mobility of seniors affects their personal or family life, but also community and public life. The factors that promote spatial mobility and those that hinder it are the subject of contemporary research. Among the topics related to ageing and old age, the autonomy of seniors, which encompasses several aspects, is also under investigation. The intersection of these two topics, i.e., spatial mobility and autonomy, raises the questions of how these phenomena and processes are related, to what extent they condition each other and, as a result, what functions mobile autonomy, so conceived, fulfils or, conversely, under what circumstances it ceases to be functional. An analysis of 24 semi-structured interviews with seniors over 70 years of age was conducted. The main objective of the study was to discover what importance seniors attach to the outdoor mobility for their individual autonomy. We deconstructed this goal into the following research questions: (a) What importance do seniors attach to the outdoor mobility modes they use? (b) What circumstances do seniors identify as affecting their mobility? (c) How do seniors respond to the limitations in their outdoor mobility?In particular, the modus of the car has been shown to be important, but the importance is differentiated according to different criteria, e.g., whether the senior drives alone, whether his/her partner drives or whether s/he relies on the help of others. A big question is how drivers cope when they stop driving or are forced to stop. The importance of the bicycle, usually linked to the wider radius of the elderly person's daily living space, depends on health, fitness, and lifestyle. From the interviews, it is evident that the situation of seniors and their coping strategies, especially in the case of advanced old age, are well characterized by their ability and commitment to walking. The analysis of the interviews leads to a typology of seniors' attitudes towards mobility and its importance for their own autonomy.
Spatial pattern of the Walkability Index, Walk Score and Walk Score modification for elderly
(MDPI, 2022) Horák, Jiří; Kukuliač, Pavel; Marešová, Petra; Orlíková, Lucie; Kolodziej, Ondřej
Contemporary cities require excellent walking conditions to support human physical activity, increase humans' well-being, reduce traffic, and create a healthy urban environment. Various indicators and metrics exist to evaluate walking conditions. To evaluate the spatial pattern of objective-based indicators, two popular indices were selected-the Walkability Index (WAI), representing environmental-based indicators, and Walk Score (WS), which applies an accessibility-based approach. Both indicators were evaluated using adequate spatial units (circle buffers with radii from 400 m to 2414 m) in two Czech cities. A new software tool was developed for the calculation of WS using OSM data and freely available network services. The new variant of WS was specifically designed for the elderly. Differing gait speeds, and variable settings of targets and their weights enabled the adaptation of WS to local conditions and personal needs. WAI and WS demonstrated different spatial pattern where WAI is better used for smaller radii (up to approx. 800 m) and WS for larger radii (starting from 800 m). The assessment of WS for both cities indicates that approx. 40% of inhabitants live in unsatisfactory walking conditions. A sensitivity analysis discovered the major influences of gait speed and the beta coefficient on the walkability assessment.
Visualising residents' fear of crime with recorded crime data from four Czech cities
(Taylor & Francis, 2022) Linhartová, Petra; Ivan, Igor; Pánek, Jiří
The paper investigates if and where registered crime and the fear of crime intersect in the four locations. This information is important to reduce crime and increase the sense of security of the population. In the past, research was applied to small parts of a city or a whole city, but not in as much detail as this paper. Our research is detailed, and at the same time is applied to four entire locations - three Czech cities (Ostrava, Olomouc, and Kolin) and one Prague district (Prague 12). We placed registered crime and fear of crime on one map to show locations where people feel afraid, where crime happens, and where both events occur together. We drew these phenomena using Moran's I in a bivariate map. The outputs will be applied by Municipal governments and police departments.
Visual processing and analysis of landslide deformation based on GNSS
(IEEE, 2021) Li, Weiguo; Ivan, Igor; Liu, Yali; Yang, Libing
For landslide surface monitoring, the Global Navigation Satellite System (GNSS) has been widely used in landslides due to its real-time, all-weather, high-precision, simple operation and a high degree of automation. However, these data are not intuitive and visual data will be more interesting for users without professional knowledge. At the same time, the conventional data representation method is in the form of curves or tables for three-dimensional data of landslide surface deformation collected by GNSS. To make the data more intuitive, clear and valuable, it is easier for people to understand the process of landslide deformation and finally realize the visualization of decision. Here we show that a polar coordinate system rather than a Cartesian coordinate system is adopted to visualize the horizontal data, which not only shows the horizontal deformation of the landslide, but also easily knows the direction of the landslide deformation. The vertical data is in the form of slices rather than curves, which not only shows the deformation of the landslide surface, but also shows the process of the vertical change of the landslide in terms of the time series. Single GNSS monitoring station is composed of a GNSS receiver, GNSS antenna with random, a solar power unit, and a network transmission module. The system can be powered by the solar energy system, which can realize 24-hour unmanned operation, 7 days a week. The system can receive satellite signals in real-time process and analyze deformation data, then it automatically broadcast early warning information. Our results demonstrate that it is a better choice that the thematic map of Geographic Information System (GIS) is a technical system for collecting, storing, managing, calculating, analyzing and displaying geographic data supported by computer hardware and software systems. Here we show that the multi-dimensional properties of deformation monitoring and multiple expressions of the attribute values are displayed synchronously in order to obtain more useful information from the visual graphics.
Shock and vibration of rainfall on rotational landslide and analysis of its deformation characteristics
(Hindawi, 2021) Li, Weiguo; Liu, Yali; Chen, Yanhong; Yang, Libing
Earthquake, flood, human activity, and rainfall are some of the trigger factors leading to landslides. Landslide monitoring data analysis indicates the deformation characteristics of landslides and helps to reduce the threat of landslide disasters. There are monitoring methods that enable efficient acquisition of real-time data to facilitate comprehensive research on landslides. However, it is challenging to analyze large amounts of monitoring data with problems like missing data and outlier data during data collection and transfer. These problems also hinder practical analysis and determination concerning the uncertain monitoring data. This work analyzes and processes the deformation characteristics of a rainfall-induced rotational landslide based on exploratory data analysis techniques. First, we found that the moving average denoising method is better than the polynomial fitting method for the repair and fitting of monitoring data. Besides, the exploratory data analysis of the Global Navigation Satellite System (GNSS) monitoring data reveals that the distribution of GNSS monitoring points has a positive correlation with the deformational characteristics of a rotational landslide. Our findings in the subsequent case study indicate that rainfalls are the primary trigger of the Zhutoushan landslide, Jiangsu Province, China. Therefore, this method provides support for the analysis of rotational landslides and more useful landslide monitoring information.
Dynamic pluvial flash flooding hazard forecast using weather radar data
(MDPI, 2021) Rapant, Petr; Kolejka, Jaromír
Pluvial flash floods are among the most dangerous weather-triggered disasters, usually affecting watersheds smaller than 100 km(2), with a short time to peak discharge (from a few minutes to a few hours) after causative rainfall. Several warning systems in the world try to use this time lag to predict the location, extent, intensity, and time of flash flooding. They are based on numerical hydrological models processing data collected by on-ground monitoring networks, weather radars, and precipitation nowcasting. However, there may be areas covered by weather radar data, in which the network of ground-based precipitation stations is not sufficiently developed or does not even exist (e.g., in an area covered by portable weather radar). We developed a method usable for designing an early warning system based on a different philosophy for such a situation. This method uses weather radar data as a 2D signal carrying information on the current precipitation distribution over the monitored area, and data on the watershed and drainage network in the area. The method transforms (concentrates) the 2D signal on precipitation distribution into a 1D signal carrying information on potential runoff distribution along the drainage network. For sections of watercourses where a significant increase in potential runoff can be expected (i.e., a significant increase of the 1D signal strength is detected), a warning against imminent flash floods can be possibly issued. The whole curve of the potential runoff development is not essential for issuing the alarm, but only the significant leading edge of the 1D signal is important. The advantage of this procedure is that results are obtained quickly and independent of any on-ground monitoring system; the disadvantage is that it does not provide the exact time of the onset of a flash flooding or its extent and intensity. The generated alert only warns that there is a higher flash flooding hazard in a specific section of the watercourse in the coming hours. The forecast is presented as a dynamic map of the flash flooding hazard distribution along the segments of watercourses. Relaying this hazard to segments of watercourses permits a substantial reduction in false alarms issued to not-endangered municipalities, which lie in safe areas far away from the watercourses. The method was tested at the local level (pluvial flash floods in two small regions of the Czech Republic) and the national level for rainfall episodes covering large areas in the Czech Republic. The conclusion was that the method is applicable at both levels. The results were compared mainly with data related to the Fire and Rescue Service interventions during floods. Finally, the increase in the reliability of hazard prediction using the information on soil saturation is demonstrated. The method is applicable in any region covered by a weather radar (e.g., a portable one), even if there are undeveloped networks of rain and hydrometric gauge stations. Further improvement could be achieved by processing more extended time series and using computational intelligence methods for classifying the degree of flash flooding hazard on individual sections of the watercourse network.
Assessment of multi-GNSS precise orbit and clock products from different analysis centers based on precise point positioning
(Akademie věd České republiky, Ústav struktury a mechaniky hornin, 2021) Li, Weiguo; Kačmařík, Michal
Performance of 24h static Precise Point Positioning (PPP) solutions based on multi-GNSS precise satellite orbit and clock products from four analysis centers and seven various constellation combinations was studied to evaluate their quality and characteristics. Data from ten European and four Chinese GNSS stations and 152 days long period from year 2020 were processed. Obtained coordinates were firstly compared with those provided by IGS final weekly combined solution. In Europe, the best agreement with this reference product was reached by solutions including Galileo signals, namely by a combination of GPS+GLONASS+Galileo systems with a mean RMS of 11 mm. This situation was different in China where inclusion of Galileo always led to worse results and the best agreement was achieved by a combination of GPS+GLONASS systems. Although product provided by German Research Center for Geosciences (GFZ) could be selected as the best performing over Europe and product by Center for Orbit Determination in Europe (CODE) over China, differences between individual precise products were mostly at a minimal level. Secondly, coordinates repeatability over the processed period was computed in order to assess the positioning stability. In this regard, the lowest values in both horizontal and vertical direction were reached by GPS+GLONASS solutions. From the perspective of precise products, the repeatability results were dependent on the selected constellation where mainly a specific behavior of product from Wuhan University (WUM) for Galileo system was observed.
A new GIS-compatible methodology for visibility analysis in digital surface models of earth sites
(Elsevier, 2021) Růžičková, Kateřina; Růžička, Jan; Bitta, Jan
As a GIS tool, visibility analysis is used in many areas to evaluate both visible and non-visible places. Visibility analysis builds on a digital surface model describing the terrain morphology, including the position and shapes of all objects that can sometimes act as visibility barriers. However, some barriers, for example vegetation, may be permeable to a certain degree. Despite extensive research and use of visibility analysis in different areas, standard GIS tools do not take permeability into account. This article presents a new method to calculate visibility through partly permeable obstacles. The method is based on a quasi-Monte Carlo simulation with 100 iterations of visibility calculation. Each iteration result represents 1% of vegetation permeability, which can thus range from 1% to 100% visibility behind vegetation obstacles. The main advantage of the method is greater accuracy of visibility results and easy implementation on any GIS software. The incorporation of the proposed method in GIS software would facilitate work in many fields, such as architecture, archaeology, radio communication, and the military.
The neural network assisted land use regression
(MDPI, 2021) Bitta, Jan; Svozilík, Vladislav; Svozilíková Krakovská, Aneta
Land Use Regression (LUR) is one of the air quality assessment modelling techniques. Its advantages lie mainly in a much simpler mathematical apparatus, quicker and simpler calculations, and a possibility to incorporate more factors affecting pollutant concentration than standard dispersion models. The goal of the study was to perform the LUR model in the Polish-Czech-Slovakian Tritia region, to test two sets of pollution data input factors, i.e., factors based on emission data and pollution dispersion model results, to test regression via neural networks and compare it with standard linear regression. Both input datasets, emission data and pollution dispersion model results, provided a similar quality of results in the case when standard linear regression was used, the R-2 of the models was 0.639 and 0.652. Neural network regression provided a significantly higher quality of the models, their R-2 was 0.937 and 0.938 for the factors based on emission data and pollution dispersion model results respectively.
Determination of gaps in the spatial accessibility of nursing services for persons over the age of 65 with lowered self-sufficiency: Evidence from the Czech Republic
(PLOS, 2021) Vrabková, Iveta; Ertingerová, Izabela; Kukuliač, Pavel
The subject of this research is one of the main preconditions for the provision of high-quality social care services for people over the age of 65 with lowered self-sufficiency. It involves the spatial accessibility of formally established nursing services examined in 76 districts of the Czech Republic. The aim of this article is to identify and evaluate the gaps in spatial accessibility of the selected residential and outpatient-clinic services at the level of districts in individual regions of the Czech Republic in 2018. A three-phase analysis was performed, including an ArcGIS network analysis, multi-criteria evaluation according to the TOPSIS method, and a correlation analysis encompassing the confidence interval gained via the Bootstrap method. Seven indicators were selected-recipients of the allowance for the care, capacity of residential and outpatient-clinic services, and four indicators of accessibility via individual and public transport within the set time intervals. The results show good availability of residential care (no gap) within 30 min. by individual and public transport in most districts (94%). However, day services centers do not have a space gap in only 28% of districts by individual transport, and 8% of districts by public transport. In the case of day care centers, 54% of districts by individual transport, and 29% of districts by public transport do not have a space gap. The results also show that the level of spatial availability of care (gaps) in the district is not related to the number of people aged 65+ with reduced self-sufficiency in the district. On the contrary, the correlation analysis shows that with the growing number of people aged 65+ with reduced self-sufficiency in the district, the capacity of residential and outpatient services increases and the gaps in spatial accessibility do not decrease.
Social media semantic perceptions on Madrid Metro system: Using Twitter data to link complaints to space
(Elsevier, 2021) Osorio-Arjona, Joaquín; Horák, Jiří; Svoboda, Radek; García-Ruíz, Yolanda
Social networks are platforms widely used by travelers who express their opinions about many services like public transport. This paper investigates the value of texts from social networks as a data source for detecting the spatial distribution of problems within a public transit network by geolocating citizens' feelings, and analyzes the effects some factors such as population or income have over that spatial spread, with the goal of developing a more intelligent and sustainable public transit service. For that purpose, Twitter data from the Madrid Metro account is collected over a two-month period. Topics and sentiments are identified from text mining and machine learning algorithms, and mapped to explore spatial and temporal patterns. Lastly, a Geographically Weighted Regression model is used to explore the causality of the spatial distribution of complaining users, by using official data sources as exploratory variables. Results show Twitter users tend to be mid-income workers who reside in peripheral areas and mainly tweet when traveling to workplaces. The main detected problems were punctuality and breakdowns in transfer stations or in central areas, mainly in the early morning of weekdays, and affected by density of points of interest in destination areas.
Radar interferometry as a comprehensive tool for monitoring the fault activity in the vicinity of underground gas storage facilities
(MDPI, 2020) Rapant, Petr; Struhár, Juraj; Lazecký, Milan
Underground gas storage facilities are an important element of the natural gas supply system. They compensate for seasonal fluctuations in natural gas consumption. Their expected lifetime is in tens of years. Continuous monitoring of underground gas storage is therefore very important to ensure its longevity. Periodic injection and withdrawal of natural gas can cause, among other things, vertical movements of the terrain surface. Radar interferometry is a commonly used method for tracking changes in the terrain height. It can register even relatively small height changes (mm/year). The primary aim of our research was to verify whether terrain behavior above a relatively deep underground gas storage can be monitored by this method and to assess the possibility of detecting the occurrence of anomalous terrain behavior in an underground gas storage area such as reactivation of faults in the area. The results show a high correlation between periodic injection and withdrawal of natural gas into/from the underground reservoir and periodic changes in terrain height above it (the amplitude of the height changes is in centimeters), which may allow the detection of anomalous phenomena. We documented special behavior of storage structures in the Vienna Basin: the areas adjacent to the underground gas storages show exactly the opposite phase of vertical movements, i.e., while the terrain above the underground reservoirs rises as natural gas is injected, the adjacent areas subside, and vice versa. Based on the analysis of geological conditions, we tend to conclude that this behavior is conditioned by the tectonic fault structure of the studied area.

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