Shoreline Changes in Tharangampadi Village,Nagapattinam District,Tamil Nadu,India—A Case Study

Coastal zone is very dynamic, being the meeting place of land and sea water. The development in coastal area and subsequent population growth have given rise to problems such as erosion, sedimentation, saltwater intrusion, degradation of natural resources, etc. Satellite data has proved to be more appropriate for change detections quantifying and monitoring coastal zones compared to conventional sources. An attempt is being made to elucidate the effect of shoreline changes with reference to the spatial and field data observed along the Tharangampadi area. The base map was prepared on 1:50,000 scale for delineation and identification of shoreline changes. The spatial variability of shoreline changes are studied using IRS 1B LISS-II 1991, IRS 1C LISS-III 2004 and IRS P6 LISS-IV and IRS 1D PAN merge data 2006. The corresponding Survey of India toposheets of 1852, 1972 and survey and land record village map of 1918 also supplemented for this study. The kind and extent of shoreline changes were investigated by using GPS during ground truth verification. The results are analyzed and presented in this paper. The study results revealed that 180 m receding of the shoreline occurred in the past 155 years.     

Hydrogeomorphological mapping in assessing ground water by using remote sensing data — A case study in lehra gaga block, sangrur district, Punjab

The paper presents the results of hydrogeomorphological mapping using IRS-IB LISS II data and evaluation of ground water prospects of each hydrogeomorphological unit in the Lehra Gaga block of Sangrur district, Punjab. The major geomorphic units identified in the area are, alluvial plain, sand dunes, palaeo channels and the Ghagar flood plain. The study area being part of alluvial plain has good to excellent ground water prospects. Field observations showed that ground water occurs under both confined and unconfined conditions with water table at shallow depth. The area on either side of the Ghagar river and along the major canals (about 46% of the total geographical area in the block) have good quality of ground water and is suitable for irrigation, whereas the water quality is marginal (sodic) in 52 per cent area of the block..     

General Entropy Model of Line Segments Uncerta,nty in GIS

Spatial data uncertainty can directly affect the quality of digital products and GIS-based decision making. On the basis of the characteristics of randomicity of positional data and fuzziness of attribute data, taking entropy as a measure, the stochastic entropy model of positional data uncertainty and fuzzy entropy model of attribute data uncertainty are proposed. As both randomicity and fuzziness usually simultaneously exist in linear segments, their omnibus effects are also investigated and quantified. A novel uncertainty measure, general entropy, is presented. The general entropy can be used as a uniform measure to quantify the total uncertainty caused by stochastic uncertainty and fuzzy uncertainty in GIS.     

Variations in annual snowline and area of an ice-covered stratovolcano in the Cordillera Ampato,Peru, using remote sensing data (1986–2014)

This research focuses on the recent variations in the annual snowline and the total glaciated area of the Nevado Coropuna in the Cordillera Ampato, Peru. Maximum snowline altitude towards the end of dry season is taken as a representative of the equilibrium line altitude of the year, which is an indirect measurement of the annual mass balance. We used Landsat and IRS LISS3 images during the last 30 years due to its better temporal coverage of the study site. It is found that there was a decrease of 26.92% of the glaciated area during 1986–2014. We calculated the anomalies in precipitation and temperature in this region and also tried to correlate the changes in glacier parameters with the combined influence of El Niño – Southern Oscillation (ENSO) and pacific decadal oscillation (PDO). It is concluded that the snowline of Nevado Coropuna has been fluctuated during ENSO, and maximum fluctuations were observed when ENSO and PDO were in phase.     

Groundwater assessment through hydrogeomorphological and geophysical survey — A case study in Godavari sub-watershed, Giridih, Bihar

Groundwater assessment has been carried out through hydrogeomorphological and geophysical survey. Remotely sensed data has been used to delineate the hydrogeomorphological units. Each hydrogeomorphological unit has been further sub-divided based on the tone, texture and pattern. These units its have been categorised based on depth of weathering, local geomorphological association, recharge characteristics etc. The top layer resistivity of hydrogeomorphological units has been analysed by electrical resistivity method. Correlation between different sub-units of same hydrogeomorphic unit and top soil resistivity has been attempted. The correlation and integration of resistivity map with geomorphological map were carried out through. ‘GRAM’ Geographic information System, This has helped in better understanding the surface resistivity pattern. These sub divisions have different geohydrological and recharge characteristics. Resistivity zonation map prepared on the basis of limited field data anfd through interpolation/extrapolation can be modified/corrected with the help of information derived from remotely sensed data to obtain more realistic picture.     

The demographic burden of population loss in US cities, 2000–2010

Journal of Geographical Systems - Although the effects of urban shrinkage on quality of life and the built environment have received a great deal of attention, the characteristics of those...     

The dynamics in the distribution of mangrove forests in Pichavaram,South India – perception by user community and remote sensing

This study aims to monitor the forest cover of Pichavaram mangroves, South India over a period of 40 years using remote sensing, and to record the status of mangroves as perceived by the local community. Out of 1471 ha of total reserved forest area, mangroves occupy 906 ha. The remote sensing maps show that there was a loss of 471 ha from 1970 to 1991 and a gain of 531 ha in 2011. Nearby 20 hamlets depend on mangroves for their livelihood. A village survey conducted at Pichavaram shows that more than 90% of the local community is well aware of the prevailing species, their importance especially after the 2004 tsunami and the impact of management practices, increased rainfall and contribution of local community in the recent increased area of mangroves. The same can be noticed from the high-resolution IKONOS image showing the artificial canal network in the restored region and from rainfall records.     

GIMMS NDVI time series reveal the extent,duration, and intensity of “blooming desert” events in the hyper-arid Atacama Desert,Northern Chile

The “blooming desert”, or the explosive development and flowering of ephemeral herbaceous and some woody desert species during years with abnormally high accumulated rainfall, is a spectacular biological phenomenon of the hyper-arid Atacama Desert (northern Chile) attracting botanists, ecologists, geo-scientists, and the general public from all over the world. However, the number of “blooming deserts”, their geographical distribution and spatio-temporal patterns have not been quantitatively assessed to date. Here, we used NDVI data from the Global Inventory Modeling and Mapping Studies (GIMMS) project to reconstruct the annual land surface phenology (LSP) of the Atacama Desert using a non-parametric statistical approach. From the reconstructed LSP, we detected the “blooming deserts” as positive NDVI anomalies and assessed three dimensions of the events: their temporal extent, intensity of “greening” and spatial extent. We identified 13 “blooming deserts” between 1981 and 2015, of which three (1997–98, 2002–03, and 2011) can be considered major events according to these metrics. The main event occurred in 2011, spanning 180 days between July and December 2011, and spread over 11,136 km² of Atacama dry plains. “Blooming deserts” in Atacama have been triggered by the accumulation of precipitation during a period of 2 to 12 months before and during the events. The proposed three-dimensional approach allowed us to characterize different types of “blooming deserts”: with longer episodes or larger spatial distribution or with different “greening” intensities. Its flexibility to reconstruct different LSP and detect anomalies makes this method a useful tool to study these rare phenomena in other deserts in the world also.     

Expansion dynamics of deciduous rubber plantations in Xishuangbanna,China during 2000–2010

Monoculture rubber plantations have been replacing tropical rain forests substantially in Southern China and Southeast Asia over the past several decades, which have affected human wellbeing and ecosystem services. However, to the best of our knowledge on the extent of rubber plantation expansion and their stand ages is limited. We tracked the spatiotemporal dynamics of deciduous rubber plantations in Xishuangbanna, the second largest natural rubber production region in China, from 2000 to 2010 using time-series data from the Phased Array type L-band Synthetic Aperture Radar (PALSAR), Landsat, and Moderate Resolution Imaging Spectroradiometer (MODIS). We found that rubber plantations have been expanding across a gradient from the low-elevation plains to the high elevation mountains. The areas of deciduous rubber plantations with stand ages ≤5, 6–10, and ≥11-year old were ~1.2 × 10⁵ ha, ~0.8 × 10⁵ ha, and ~2.9 × 10⁵ ha, respectively. Older rubber plantations were mainly located in low-elevation and species-rich regions (500–900 m) and younger rubber trees were distributed in areas of relative high-elevation with fragile ecosystems. Economic and market factors have driven the expansion of rubber plantations, which is not only a threat to biodiversity and environmental sustainability, but also a trigger for climatic disasters. This study illustrates that the integration of microwave, optical, and thermal data is an effective method for mapping deciduous rubber plantations in tropical mountainous regions and determining their stand ages. Our results demonstrate the spatiotemporal pattern of rubber expansions over the first decade of this century.     

Whither goes the “maps” course? Maintaining map-use concepts,skills, and appreciation in GIS&T curricula

Popular and professional interest in maps and map-making has never been greater. Despite this engagement, introductory skills courses in “map use” have largely disappeared in undergraduate geography and cartography programs at US universities, with research indicating that both map-use course enrollments and the existence of such courses themselves are on the decline. While the map-use course and its content may have been replaced by, repackaged as, or incorporated into an integrated geographical information systems-cartography–remote sensing foundations course, how do we ensure that an understanding of maps and their unique characteristics is not lost in the mix? This essay describes a recent course redesign experience incorporating information literacy, technology fluency, and spatial thinking principles to maintain map-use concepts, skills, and appreciation in an introductory geographic information science and technology (GIS&T) foundations course, meeting both GIS&T and general education curricular goals.     

Airborne remote sensing of spatiotemporal change (1955–2004) in indigenous and exotic forest cover in the Taita Hills,Kenya

We studied changes in area and species composition of six indigenous forest fragments in the Taita Hills, Kenya using 1955 and 1995 aerial photography with 2004 airborne digital camera mosaics. The study area is part of Eastern Arc Mountains, a global biodiversity hot spot that boasts an outstanding diversity of flora and fauna and a high level of endemism. While a total of 260 ha (50%) of indigenous tropical cloud forest was lost to agriculture and bushland between 1955 and 2004, large-scale planting of exotic pines, eucalyptus, grevillea, black wattle and cypress on barren land during the same period resulted in a balanced total forest area. In the Taita Hills, like in other Afrotropical forests, indigenous forest loss may adversely affect ecosystem services.     

Knowledge‐based digital mapping of vegetation types in Big Bend National park,Texas

A knowledge‐based strategy is utilized to develop a model for performing automated mapping of twenty vegetation cover types occurring within Big Bend National P ark, Texas. Many of the cover types found within this desert region cannot be reliably identified solely on a spectral basis, even on large‐scale, aircraft‐borne color imagery. Positive identification may be improved, however, by incorporating additional spatial information that may distinguish given cover types on a non‐spectral basis. In this study, digital soils and digital terrain data are utilized with spectral imagery from Landsat Thematic Mapper.

This knowledge‐based strategy is comprised of three primary elements: knowledge acquisition, rules development, and model structuring. Knowledge acquisition identifies the vegetation composition and non‐vegetative site characteristics associated with the occurrence of each cover type. Rules development compares and contrasts these characteristics among pairs of cover types and their subsets Model structuring places the presumed digital analogs of these characteristics within a multi‐layered classification.

After implementing the automated mapping model, its quality was evaluated with an accuracy assessment. Based upon the cover types field‐truthed at 142 sites within the park, the model performed at an 72% level of accuracy. For comparative purposes, a traditional supervised (spectral, statistical) classification yielded a 42% accuracy. The superiority of the model is attributed to its incorporation of knowledge‐based information; in essence, identification by considering only those cover types likely to occur over given spectral and physiographic conditions.     

Identification of Landslide Scars in the Region of the Serra do Mar,São Paulo State,Brazil, Using Digital Image Processing and Spatial Analysis Tools

The objective of the present study, developed in a mountainous region in Brazil where many landslides occur, is to present a method for detecting landslide scars that couples image processing techniques with spatial analysis tools. An IKONOS image was initially segmented, and then classified through a Batthacharrya classifier, with an acceptance limit of 99%, resulting in 216 polygons identified with a spectral response similar to landslide scars. After making use of some spatial analysis tools that took into account a susceptibility map, a map of local drainage channels and highways, and the maximum expected size of scars in the study area, some features misinterpreted as scars were excluded. The 43 resulting features were then compared with visually interpreted landslide scars and field observations. The proposed method can be reproduced and enhanced by adding filtering criteria and was able to find new scars on the image, with a final error rate of 2.3%.     

Groundwater Potential Zoning in Thirumanimuttar Sub-Basin Tamilnadu, India—A GIS and Remote Sensing Approach

The main objective of the study is to identify groundwater potential zones in Thirumanimuttar basin with an integrated approach using Remote Sensing and geographical information system(GIS).FCC Image of Landsat TM 30 m resolution data and topographic maps has been used to generate thematic maps like geology,geomorphology,lineament and lineament density,drain-age,drainage density,and slope map of the study area.A number of geomorphic units such as Denudational hills,structural hills,Bajadas,Colluvial plain,Pediplain,Deep Pediment and Alluvial plains have been observed.A composite groundwater potential map has been generated as very high,high,medium,low and very low based on the groundwater availability area.The upper,mid-dle and downstream of the basins have been identified as potential zones for groundwater exploration.The regions of lineaments and intersecting lineaments proved for groundwater potential zones.The data generated was validated with field checks and ob-served to be in conformity with the same.     

Hydrological and hydrodynamic modeling for flood damage mitigation in Brahmani–Baitarani River Basin,India

Stream flow forecast and its inundation simulations prior to the event are an effective and non-structural method of flood damage mitigation. In this paper, a continuous simulation hydrological and hydrodynamic model was developed for stream flow forecast and for spatial inundation simulation in Brahmani–Baitarani river basin, India. The hydrologic modelling approach includes rainfall-run-off modelling, flow routing, calibration and validation of the model with the field discharge data. CARTOSAT Digital Elevation Model of 30 m resolution, land use/land cover derived from the Indian Remote Sensing Satellite (IRS-P6) AWiFS and soil textural data of the study area were used in the modelling to compute topographic and hydraulic parameters. The hydrological model was calibrated with the help of field observed discharge data of 2006 and 2009 and validated with the data of 2008 and 2011. From the results, it is found that computed discharges are very well matching well with the observed discharges. The developed model can provide the stream flow forecast with more than 30 h lead time. Possible flood inundations were simulated using hydrodynamic modelling approach. CARTO Digital Elevation Model of 10 m resolution, landuse and the computed flood hydrographs were used in inundation simulations.     

Hybrid spatiotemporal simulation of future changes in open wetlands: A study of the Abitibi-Témiscamingue region,Québec,Canada

Among the most productive ecosystems around the world, wetlands support a wide range of biodiversity such as waterfowl, fish, amphibians, plants and many other species. They also provide ecosystem services that play important roles in relation to nutrient cycling, climate mitigation and adaptation, as well as food security. In this research, we examined and projected the spatiotemporal trends of change in open wetlands by coupling logistic regression, Markov chain methods and a multi-objective land allocation model into a hybrid geosimulation model. To study the changes in open wetlands we used multi-temporal land cover information interpreted from LANDSAT images (1985, 1995, and 2005). We predicted future spatial distributions of open wetlands in the administrative region of Abitibi-Témiscamingue, Quebec, Canada for 2015, 2025, 2035, 2045 and 2055. A comparison and assessment of the model’s outcomes were performed using map-comparison techniques as well as landscape metrics. Change analysis between 1985 and 2005 showed an increase of about 63% in open wetlands, while simulation results indicated that this tendency would persist into 2055 with a continuous augmentation of open wetlands in the region. The spatial distribution of predicted trends in open wetlands could provide support to local biodiversity assessments, management and conservation planning of the open wetlands in Quebec, Canada.     

Vegetation recovery monitoring over the waste dump in Haizhou opencast coalmine area,China, during 1975–2000 using NDVI and VF index

Vegetation condition monitoring has been done from 1975 to 2000 in the waste dump of Haizhou opencast coalmine area, China, using remote sensing techniques with the objective of improving our understanding of the temporal and spatial variation of vegetation recovery in the mining dump. Four historical vegetation indexes (NDVI, VF, soil brightness and vegetation greenness) from two Landsat 2 MSS images and two Landsat 5 TM images are extracted and analyzed. For the purpose of comparison and analysis two improved techniques such as normalization grading of change slope and image segmentation were used in this study. Based on the results obtained through the above analysis two conclusions are derived: (1) vegetation recovery in the study area is in an improved condition, (2) two remote sensing based vegetation indexes such as VF and NDVI are the optimal parameters to monitor vegetation condition, which could be used as the indicators of land reclamation progress in the mining area.