Google EarthTM Research Articles

Pattern Classification Technique to Assess Land Use/Cover Changes in Granite Quarry Area of Dharmapuri and Krishnagiri Districts of Tamilnadu

The rapid phase of urbanization and infrastructure development in Krishnagiri Distirct has been observed recently. The unique characteristics of the granite deposits in Krishnagiri and Dharmapuri Districts of Tamilnadu resulted in making the country a global producer of the granite rocks. This led to intensified quarrying activities between Dharmapuri and Krishnagiri. However, this surface mining method, has a potential to impact the environment in a negative way causing loss in vegetation, depletion of natural resources, increases the Temperature, loss of scenic beauty and contamination of surface water resources. To assess the land cover changes caused by granite quarrying activities, remotely sensed data in the form of Landsat images between 2000 and 2017 were used. Pattern classification was used to create maps. Accuracy assessment using Google EarthTM as a reference data yielded an overall accuracy of 88%. The post classification change detection method was used to value the land cover changes within the granite quarries. Granite quarries increased by 2562.78 ha while formation of quarry lakes increased to 5.3ha over the 18-year period. Vegetation cover decreased by 1521ha in area while 18.3ha bare land was lost during the same period. This study demonstrated the utility of remote sensing to detect changes in land cover within granite quarries.

A new method for assessing river ecosystem services and its application to rivers in Scotland with and without nature conservation designations

AbstractBased on a paired analysis, we describe a method for evaluating the potential of rivers with different physical characteristics to provide ecosystem services. Scores based on an extensive scientific literature review and expert opinion were applied to four sets of rivers in Scotland, with each pair comprising one river with a statutory nature conservation designation and one where such designations were largely absent. Data on physical habitat features and land cover were extracted manually from Google Earth™, based upon a previously published method expanded here to take account of cultural ecosystem services. Twenty physical habitat features and land‐cover types and 13 ecosystem services (four provisioning, three regulating, and six cultural) were used in the analysis. Notable developments on the earlier approach included the full integration of cultural ecosystem services alongside provisioning, regulating, and supporting services; introduction of confidence levels to river feature–ecosystem service linkages; and incorporation of valley floor surface area into one of the two scoring systems. Ecosystem scores for 500 m reaches along each river from source to mouth were calculated using Microsoft Excel, with results showing high reach‐to‐reach variability within individual rivers and significant differences between paired rivers. The four rivers with statutory nature conservation designations provided a greater range and typically higher ecosystem service scores than those with little or no designation, a result that has significant implications for river conservation and for framing catchment‐level conservation policy.

EVALUATION OF THE SPATIAL DISTRIBUTION OF EVACUATION CENTERS IN METRO MANILA, PHILIPPINES

Abstract. In a densely populated and hazard-prone megalopolis like Metro Manila, the ability to execute a rapid evacuation protocol is crucial in saving lives and minimizing the damage during disastrous events. However, there is no centralized database on the location of evacuation centers (ECs) in Metro Manila and the available lists are not up-to-date. This study geotagged the current list of ECs in Metro Manila obtained from different government agencies to evaluate the spatial distribution using Geographical Information System (GIS). This is important since the immediate evacuation of residents depends on the proximity and safe location of the ECs. A total of 870 ECs were geo-tagged and validated using the street view of Google EarthTM. EC-to-population ratios were calculated for each of the 16 cities and one municipality of Metro Manila. Values range from ~3,000 to 81,000 persons per EC. Distance analysis using Thiessen Polygon shows that the ECs are not evenly distributed with proximity areas ranging from 0.0009 to 9.5 km2. Out of the total number of mapped ECs, 392 (45%) are situated in flood-prone areas while 108 (12%) are within the 1-km buffer hazard zone of an active faultline. Re-evaluation of the locations and the number of ECs per city or municipality is highly recommended to facilitate prompt evacuation when disasters strike.

Evaluating sources of uncertainty and variability in rock glacier inventories

AbstractThis paper aims to evaluate sources of uncertainty and variability associated with rock glacier inventories compiled from remotely sensed imagery. To this end, we ran three mapping exercises in Kaiserbergtal, Austria. To evaluate interactions between mapping style and imagery resolution, we asked six operators to map and assess the degree of activity of all rock glaciers they could identify – first on Google Earth™ (GE) imagery and then on a set of higher‐resolution orthophotos and LiDAR‐derived images (LO) (Exercise 1). To compare the mapping attributes on a common set of rock glaciers, we asked 14 operators to delineate the outline of four designated rock glaciers (Exercise 2) and to classify the activity of 15 designated rock glaciers (Exercise 3) on LO. Results show strikingly high inter‐operator variability. Specifically, we show that the number of mapped rock glaciers on GE can vary up to a factor of 3, and that using LO lowers this figure to a factor of 2, while producing an increase in the number of mapped landforms, which become systematically smaller (Exercise 1). Examination of polygon outlines identifies highest inter‐operator variability at the transition with the rooting zone and, in polymorphic rock glaciers, on adjacent creeping lobes. Variability is higher for relict landforms (Exercise 2). Operators’ activity assessments, evaluated against an independent quantitative activity index (RGI), display reasonable agreement for active and relict landforms, whereas inactive counterparts meet least consensus and therefore are problematic (Exercise 3). We further show that this variability in mapping outcomes propagates across compound variables, and must be considered when assessing uncertainties and confidence levels of environmental evaluations that rely on rock glacier inventories, such as the lower altitudinal limit of discontinuous permafrost, or water storage potential. We call for an international effort to establish guidelines for rock glacier classification and mapping, towards more homogeneous inventories. © 2019 John Wiley & Sons, Ltd.

Monitoring the critically endangered Clanwilliam cedar with freely available Google Earth imagery.

Monitoring of species and populations is essential for biodiversity observation and reporting at local, national and global scales, but can be an exceedingly difficult task for many, if not most, species. We tested the viability of using Google Earth™ imagery to manually map and monitor all individuals of the critically endangered Clanwilliam cedar, Widdringtonia wallichii Endl. ex Carrière, across its global native distribution; the remote and rugged Cederberg mountains. Comparison with sampling from field surveys reveals this to be a highly efficient and effective method for mapping healthy adult tree localities, but it fails to detect small or unhealthy individuals with green canopies <4 m2, or discern the number of individuals in clumps. This approach is clearly viable as a monitoring tool for this species and, with the rapid progress being made in machine learning approaches and satellite technology, will only become easier and more feasible for a greater number of species in the near future. Sadly, our field surveys revealed that the number of trees that have recently died (dead leaves still present) outnumbered live trees by a ratio of 2:1.

Evaluation of User Performance in Interactive and Static 3D Maps

Interactive 3D visualizations of geospatial data are currently available and popular through various applications such as Google EarthTM and others. Several studies have focused on user performance with 3D maps, but static 3D maps were mostly used as stimuli. The main objective of this paper was to identify differences between interactive and static 3D maps. We also explored the role of different tasks and inter-individual differences of map users. In the experimental study, we analyzed effectiveness, efficiency, and subjective preferences, when working with static and interactive 3D maps. The study included 76 participants and used a within-subjects design. Experimental testing was performed using our own testing tool 3DmoveR 2.0, which was based on a user logging method and open web technologies. We demonstrated statistically significant differences between interactive and static 3D maps in effectiveness, efficiency, and subjective preferences. Interactivity influenced the results mainly in ‘spatial understanding’ and ‘combined’ tasks. From the identified differences, we concluded that the results of the user studies with static 3D maps as stimuli could not be transferred to interactive 3D visualizations or virtual reality.

Patch-Based Assessments of Shifting Cultivation Detected by Landsat Time Series Images in Myanmar

Shifting cultivation is a widely practiced agriculture system in the tropics. Regardless of the dominant land use, the dynamics of shifting cultivation over large areas are of limited knowledge. We conducted patch-based assessments and characterization of shifting cultivation extracted from already developed dataset, which detected shifting cultivation by a trajectory-based analysis using annual Landsat TM/ETM+/OLI time series images from 2000 to 2014 in Myanmar. An accuracy assessment was conducted in terms of the size and number of cleared areas compared with reference polygons of shifting cultivation, which were manually delineated by visual interpretation using Landsat and high-resolution satellite images from Google Earth™ in the selected areas. The producer’s and user’s accuracies in detecting the number of shifting cultivation patches were 78.1% and 88.4%, respectively. In whole study area, the probability of disturbances caused by shifting cultivation was significantly affected by distance to the nearest village, indicating the importance of accessibility from residences. The number of shifting cultivation patches showed a decreasing trend in this region and it will lead to less cleared forests such as located far from residences. These dynamics of shifting cultivation have possibility to affect the mosaic patterns of landscape and function maintained in the landscape in this region.

New Hampshire Department of Transportation Statewide Noise Barrier Study

This paper presents the results of a statewide noise barrier study for the New Hampshire Department of Transportation (NHDOT). The feasibility and reasonableness of noise barriers throughout the state has been evaluated according to NHDOT acoustical and cost-effectiveness criteria. The study has provided the DOT with an estimate of the potential noise barrier material costs associated with a newly implemented Type II noise barrier program. The study also has identified municipalities that the DOT can coordinate with for enacting noise-compatible planning regulations. The paper describes the methodology used to develop the screening-level noise barrier evaluation. Highway noise levels throughout the state and the distances from the highway where noise levels exceed the noise abatement criteria were determined. A method to predict the noise reduction of barriers (insertion loss) based on a simple geometrical relationship of receptors and potential noise barriers was established and has been shown to correlate well to detailed traffic noise models using actual roadway and terrain geometry. The simplified prediction method was used to evaluate over 300 miles of highway, 300 candidate noise barrier study areas, and over 30,000 receptors. This screening-level modeling approach is critical to the practicality of using the Traffic Noise Model across the entire state given the significant number of receptors and noise barrier study areas. The results of the study including information about all 30,000 receptors and 300 noise barrier study areas were collected in Google Earth™ data files for easy access when the DOT responds to noise complaints from the public.

Low cost poplar inventory in the plain of Piemonte (Italy)

The forest inventory is an important tool to know the current and to estimate the future wood availability for industry. Generally it request high economic and time costs if based on direct sampling on the areas or on classification of aerial photo or satellite images. The paper shows a methodology based on open source software (QGIS®) and images free available on the web (trough ‘Google Earth TM ’ software) to carry out a forest inventory particularly regarding poplar stands surface. This cultivation in Italy is characterized by short rotation, about ten years, and the wood is a row material very important for the industry, particularly for plywood. The results of an experimental survey located in the plain of Piemonte Region (north-west Italy) are presented in order to evaluate the timing of completion and the efficiency of the methodology. Data of land cover, divided by poplars, other forest plantations, and natural forests are showed and compared with old inventories, carried out with traditional methods. The evidence of reduction of costs in term of man involved, time, and materials is counterbalanced by some problems due to different age of the web images; however, this alternative methodology, applied by an experienced operator can ensure a good level of precision for the purposes required, with very low costs.

Glacier recession and glacial lake outburst flood studies in Zanskar basin, western Himalaya

Glacier recession and formation of glacial lakes along with outburst flood hazards are increasing in response to changing climate in the Himalayan region. This study describes evolution of Dalung and Padam glaciers and their associated lakes employing multi-temporal datasets of Landsat (MSS, TM, ETM+), Indian Remote Sensing LISS-III, Google EarthTM, ASTER GDEM and Survey of India topographic maps. The Dalung Glacier (DG) and Lake (DL) are present in Suru River catchment whereas the Padam Glacier (PG) and Lake (PL) are present in Tsarap River catchment of Zanskar basin, western Himalaya. From 1962 to 2015; the DG and PG have shrunk at different rates. The DG has shrunk by 2.6 ± 0.56 km2 (19.2 ± 4.1%) at a rate of 0.05 ± 0.01 km2 a−1 whereas, the PG has shrunk by 3.4 ± 0.65 km2 (12.7 ± 2.4%) at a rate of 0.06 ± 0.01 km2 a−1. The frontal recession was recorded as 1.240 ± 0.02 km (15.7 ± 2.0%) at a rate of 20 ± 0.4 m a−1 for DG and 2.690 ± 0.5 m (21.3 ± 2.1%) at a rate of 50.7 ± 0.1 m a−1 for PG. Consequently, the proglacial glacial lakes have formed indicating an expansion of 20 ± 3.4% (DL) and 58 ± 4.5% (PL) during 1990–2015. Using integrated criteria of standard indices for the identification of potentially dangerous glacial lakes (PDGLs), the lakes were found to be vulnerable and have a potential to cause breaching in the coming years. In order to provide inputs for the emergency action plan, one dimensional MIKE 11 Model was used to generate the peak flood hydrographs at the lake and other vulnerable sites downstream. Highest peak discharge of 3361.7 m3 s−1 (DL) and 4210.3 m3 s−1 (PL) were estimated at the lake sites which has reduced to 1520.9 m3 s−1 and 1722.4 m3 s−1 respectively at the outlet sites. The reduced discharge at downstream sites still bears the potential to create dangerous flood hazards.

Virtual globes for UAV-based data integration: Sputnik GIS and Google Earth™ applications

ABSTRACTThe integration of local measurements and monitoring via global-scale Earth observations has become a new challenge in digital Earth science. The increasing accessibility and ease of use of virtual globes (VGs) represent primary advantages of this integration, and the digital Earth scientific community has adopted this technology as one of the main methods for disseminating the results of scientific studies. In this study, the best VG software for the dissemination and analysis of high-resolution UAV (Unmanned Aerial Vehicle) data is identified for global and continuous geographic scope support. The VGs Google Earth and Sputnik Geographic Information System (GIS) are selected and compared for this purpose. Google Earth is a free platform and one of the most widely used VGs, and one of its best features its ability to provide users with quality visual results. The proprietary software Sputnik GIS more closely approximates the analytical capacity of a traditional GIS and provides outstanding advantages, such as DEM overlapping and visualization for its dissemination.

Simulation and Feasibility Studies of Rooftop PV System for University Campus Buildings in Surabaya, Indonesia

Present work simulates and analyzes the rooftop photovoltaic (PV) system on buildings roofs of the University of Surabaya, Indonesia for electricity power generation. The work also to calculate greenhouse gas (GHG) emission reduction that can be obtained by PV system mounted on the building roofs. The surface area of the roofs was determined using Polygon feature of Google Earth TM . The energy output of the system was simulated with SolarGIS pvPlanner software program. The grid-connected PV system type was chosen in the simulation. Greenhouse gas (GHG) emission reduction analysis was carried out using RETScreen program simulation. It was found that about 10,353 m 2 of the rooftop of the university buildings could be used for panel installation. The total capacity of the panels is found about 2,070 kWp with total electricity production is about 3,180 MWh per year and could supply up to 80% of the campus energy demand. The system would serve as a means of reducing 3,367.6; 2,477.2, or 1,195.7 tons of CO 2 to the atmosphere in comparison to the same amount of electricity produced by burning coal, oil, or natural gas respectively. The unit cost of PV electricity was found ranging from 0.10 – 0.20 USD/kWh. From economic aspects, the rooftops PV system has the potential to provide power at a competitive cost in comparison to other alternative options of power generation.

Glacier and glacial lake classification for change detection studies using satellite data: a case study from Baspa basin, western Himalaya

Using high-resolution Google EarthTM images in conjunction with Landsat images, the glaciers and lakes in the Baspa basin are classified to explore the recent changes. A total number of 109 glaciers (187 ± 3.7 km2) are mapped and subsequently classified as compound valley glaciers, simple valley glaciers, cirques, niches, glacieretes and ice aprons. The compound and simple valley glaciers contribute 67.1 ± 1.3% and 19.8 ± 0.3% to the total glacier cover of the basin. Similarly, a total number of 129 glacial lakes (0.360 ± 0.007 km2) are identified. From 1976 to 2011, the compound valley glaciers have lost a small area of 10.3 ± 0.03% at a rate of 0.41 ± 0.002 km2 a-1, whereas the niche glaciers have lost higher area of 40.1 ± 0.001% at a rate of 0.04 ± 0.0001 km2 a-1. Change detection of two benchmark glacial lakes revealed a progressive expansion during recent decades. The Baspa Bamak proglacial lake has expanded from 0.020 ± 0.0004 km2 (2000) to 0.069 ± 0.001 km2 (2011). Due to the complete loss of source ice, another glacial lake has expanded from 0.09 ± 0.001 km2 (1994) to 0.10 ± 0.002 km2 (2011). During the study period, the mean annual temperature that is Tavg, Tmin and Tmax have increased significantly at the 95% confidence level by 1.5 oC (0.070 °C a-1), 1.8 oC (0.076 °C a-1) and 1.6 oC (0.0071 °C a-1) from 1985 to 2008. However, the precipitation has decreased significantly from 1976 and 1985 to 2008.

Deep-learning Versus OBIA for Scattered Shrub Detection with Google Earth Imagery: Ziziphus lotus as Case Study

There is a growing demand for accurate high-resolution land cover maps in many fields, e.g., in land-use planning and biodiversity conservation. Developing such maps has been traditionally performed using Object-Based Image Analysis (OBIA) methods, which usually reach good accuracies, but require a high human supervision and the best configuration for one image often cannot be extrapolated to a different image. Recently, deep learning Convolutional Neural Networks (CNNs) have shown outstanding results in object recognition in computer vision and are offering promising results in land cover mapping. This paper analyzes the potential of CNN-based methods for detection of plant species of conservation concern using free high-resolution Google Earth TM images and provides an objective comparison with the state-of-the-art OBIA-methods. We consider as case study the detection of Ziziphus lotus shrubs, which are protected as a priority habitat under the European Union Habitats Directive. Compared to the best performing OBIA-method, the best CNN-detector achieved up to 12% better precision, up to 30% better recall and up to 20% better balance between precision and recall. Besides, the knowledge that CNNs acquired in the first image can be re-utilized in other regions, which makes the detection process very fast. A natural conclusion of this work is that including CNN-models as classifiers, e.g., ResNet-classifier, could further improve OBIA methods. The provided methodology can be systematically reproduced for other species detection using our codes available through (https://github.com/EGuirado/CNN-remotesensing).

ASSESSING LAND COVER CHANGES CAUSED BY GRANITE QUARRYING USING REMOTE SENSING

Abstract. Dimension stone quarrying in the area between Rustenburg and Brits in the North West Province of South Africa has been in existence for over 70 decades. The unique characteristics of the granite deposits in South Africa resulted in making the country a global producer of the granite rocks. This led to intensified quarrying activities between Rustenburg and Brits town. However, this surface mining method, has a potential to impact the environment in a negative way causing loss in vegetation, depletion of natural resources, loss of scenic beauty and contamination of surface water resources. To assess the land cover changes caused by granite quarrying activities, remotely sensed data in the form of Landsat images between 1998 and 2015 were used. Supervised classification was used to create maps. Accuracy assessment using Google EarthTM as a reference data yielded an overall accuracy of 78 %. The post classification change detection method was used to assess land cover changes within the granite quarries. Granite quarries increased by 1174.86 ha while formation of quarry lakes increased to 5.3 ha over the 17-year period. Vegetation cover decreased by 1308 ha in area while 18.3 ha bare land was lost during the same period. This study demonstrated the utility of remote sensing to detect changes in land cover within granite quarries.

Yardang geometries in the Qaidam Basin and their controlling factors

The hyperarid Qaidam Basin features extensive fields of yardangs (covering an area of ~40,000km2) sculpted in tectonically folded sedimentary rocks. We extracted the geometries of 16,749 yardangs, such as length-to-width ratio (L/W), spatial density, and spacing, from multi-source remote sensing data provided by Google Earth™. We classified the yardangs into four types based on their L/W: short-axis (1–2), whale-back (2–6), hogsback (6–10) and long-ridge (10−210). We interpreted the yardang geometries in the context of their geologic setting (bedding orientation, location along anticline crests or syncline troughs, and lithologic heterogeneity). Our results show that the yardang geometries in the Qaidam Basin are mainly controlled by the structural geology and rheology of the sedimentary rocks (e.g., strike and dip of bedding, the presence or absence of interbedded soft and hard beds, and structural position with folds), the angle between geomorphically-effective wind directions and the strike of bedding, and the relative cumulative wind shear force where two geomorphically-effective wind directions are present. Our analysis revealed the following: 1) nearly 69% of the yardangs with long-ridge and hogsback geometries are distributed in syncline areas whereas 73% of the yardangs with short-axis geometries are distributed in anticline areas; 2) the L/W ratio of yardangs exposed along the windward limbs of anticlines is lower than that of yardangs exposed along the leeward limbs; and 3) in the westernmost parts of the basin, yardangs are locally sculpted into mounds by two geomorphically-effective wind directions.

Rip current evidence by hydrodynamic simulations, bathymetric surveys and UAV observation

Abstract. The prediction of the formation, spacing and location of rip currents is a scientific challenge that can be achieved by means of different complementary methods. In this paper the analysis of numerical and experimental data, including RPAS (remotely piloted aircraft systems) observations, allowed us to detect the presence of rip currents and rip channels at the mouth of Sele River, in the Gulf of Salerno, southern Italy. The dataset used to analyze these phenomena consisted of two different bathymetric surveys, a detailed sediment analysis and a set of high-resolution wave numerical simulations, completed with Google EarthTM images and RPAS observations. The grain size trend analysis and the numerical simulations allowed us to identify the rip current occurrence, forced by topographically constrained channels incised on the seabed, which were compared with observations.

Mapping 2000–2010 Impervious Surface Change in India Using Global Land Survey Landsat Data

Understanding and monitoring the environmental impacts of global urbanization requires better urban datasets. Continuous field impervious surface change (ISC) mapping using Landsat data is an effective way to quantify spatiotemporal dynamics of urbanization. It is well acknowledged that Landsat-based estimation of impervious surface is subject to seasonal and phenological variations. The overall goal of this paper is to map 2000–2010 ISC for India using Global Land Survey datasets and training data only available for 2010. To this end, a method was developed that could transfer the regression tree model developed for mapping 2010 impervious surface to 2000 using an iterative training and prediction (ITP) approachAn independent validation dataset was also developed using Google Earth™ imagery. Based on the reference ISC from the validation dataset, the RMSE of predicted ISC was estimated to be 18.4%. At 95% confidence, the total estimated ISC for India between 2000 and 2010 is 2274.62 ± 7.84 km2.

The Economic Value of Tree Preservation in a Weak Land Development Market Region

New residential development is most often a death sentence for the trees that stand in its way. This behavior might be altered if developers thought there was an economic value to being more selective. Unfortunately, the relationship between tree preservation and new development is not well studied. The purpose of this study was to characterize the economic value gained from the preservation of mature trees during the land development process. The study focused on six counties constituting the greater Cleveland, Ohio, U.S., real estate and land development market. A mixed quantitative and qualitative approach was used. GIS-based data and a series of hedonic models determined the value of tree canopy associated with new home sale prices from 2009 to 2011. Qualitative interviews of development and real estate professionals revealed a nuanced association of value and challenges to tree preservation during the residential land development process. Previous methods for estimating the economic value of trees were moved forward through aerial location of trees on parcels using Google Earth™ and the National Agricultural Imagery Program (NAIP) data and through the mixed-method approach. The study provided information to a state-level agency managing the state’s incentive-based smart growth program.

What path and how fast? The effect of flight time and path on user spatial understanding in map tour animations

ABSTRACTGIScience scholars have identified map tours as an important visualization type for communicating spatial information: map tours are animations where the virtual camera moves through space and are common on the web, mobile devices, and television. Understanding how to enhance their effectiveness is timely because of recent, growing interest in virtual reality and animated map presentation tools such as Esri Story Maps™ and Google Earth™ tours. Despite this popularity, little empirical evidence exists about how people learn from map tours and how they should best be designed to improve effectiveness. This research is aimed at answering that need. An empirical study is described, which was designed to understand how virtual camera speed, path, and dynamic tilting within a map tour influence subjects’ ability to develop survey knowledge. The results of the experiment show that paths encompassing overviews of the landscape improve the viewer’s ability to build up survey knowledge; that tilting appears to have a much weaker effect; and that combining fast speed and a difficult path within a map tour increases the viewer’s cognitive load.