Interpretation Of Topographic Maps Research Articles

Eastern Continental Divide Origin in the Blacksburg, Virginia Area Determined by Topographic Map Interpretation, USA

Published geology literature addresses only a small fraction of the Blacksburg, Virginia region topographic map drainage divide evidence. This situation probably arises because the accepted geology and glacial history paradigm (accepted paradigm) does not explain most topographic map drainage divide evidence (anywhere). A new and fundamentally different geology and glacial history paradigm (new paradigm) which appears to explain most topographic map drainage divide evidence sees the Eastern Continental Divide in the Blacksburg area as being located along the rim of a continental ice sheet created and occupied deep “hole” with the rim being uplifted as immense and prolonged southwest-oriented meltwater floods flowed across the region. From the new paradigm perspective northwest-oriented New River valley headward erosion into the rising deep “hole” rim (from the deep “hole”) upon reaching the Blacksburg region beheaded and reversed southwest-oriented floodwaters (probably aided by deep “hole” rim uplift) to create today’s northeast- and northwest-oriented New River. Headward erosion of the southeast-oriented Roanoke River valley and subsequently the southeast-oriented James River valley (both from the Atlantic Ocean) then created the Roanoke River-New River and James River-New River drainage divides (both are Eastern Continental Divide segments) and the James River-Roanoke River drainage divide by beheading and reversing southwest-oriented floodwaters which had been flowing in diverging and converging channels (which had been eroded headward in northeast directions along less resistant bedrock units from the New River valley). This scenario explains most through valleys (valleys crossed by drainage divides), barbed tributaries, river direction changes, and water gaps seen on Blacksburg area detailed topographic maps and does not see significant changes taking place since the southwest-oriented floods ended. The accepted and new paradigms are incommensurable which according to Thomas Kuhn means one paradigm should not be used to judge the other.

Teaching topography using 3D printed terrain in an introductory earth science course: A pilot study

Topographic maps are a common form of 3D surface elevation data represented as a 2D display. Despite their use in geoscience courses, many students find learning to effectively read and interpret these maps challenging. Here, we present a tool for teaching topographic map interpretation using 3D printed terrain. The terrain was 3D printed from a portion of the quadrangle map used in an introductory earth science course for non-science majors. Students placed the ∼12 cm square terrain directly on the corresponding area of the paper topographic map, in order to see the landscape. Student learning was compared between an original version of the topography lab and the same lab with the addition of the 3D printed terrain, using the Modified Topographic Map Assessment (MTMA) administered as a pre- and posttest with each group. As measured by pretest scores on the MTMA, students in the original (n = 54) and 3D print terrain tool (n = 24) groups had comparable incoming topographic map interpretation skills (t(75) = .98, p = .33). Pre- to posttest MTMA scores did not significantly improve in the original lab group (M = 0.63, SD = 3.13, t(53) = 1.48, p = .15) but did in the 3D print terrain group (M = 1.96, SD = 2.97, t(23) = 3.23, p = .004) with a moderate effect size (d = .53). Results of this pilot study suggest that 3D printed terrain shows promise as a teaching tool that could be adapted to multiple uses including K-12 classes and upper division earth science courses.

North Platte River-South Platte River Confluence Area Drainage System History as Determined by Topographic Map Interpretation: Western Nebraska, USA

Detailed topographic maps of the western Nebraska North Platte River-South Platte River confluence area show a low relief and gently sloping southeast-oriented upland surface, asymmetrical drainage divides, nearly adjacent and parallel east-oriented North and South Platte River valley segments, barbed tributaries, and shallow divide crossings (low points along drainage divides) in a region south of the Nebraska Sand Hills and at the Nebraska loess region’s western margin. Published interpretations of North and South Platte River confluence area landforms (referred to as the accepted paradigm) do not explain most drainage features and are compared with a new paradigm’s interpretations to determine which of the two paradigms explains the regional drainage history and related surface features in a simple and consistent manner. New paradigm interpretations require large sheets of slowly-moving southeast-oriented water to have flowed toward what was probably an actively eroding Republican River valley and to have shaped the upland surface while the Platte and North and South Platte River valleys eroded headward into and across the region so as to create the asymmetric drainage divides, barbed tributaries, and shallow divide crossings. These new paradigm interpretations are consistent with each other and with recently published new paradigm interpretations of upstream North and South Platte River drainage system history. New paradigm interpretations also suggest the adjacent Nebraska Sand Hills developed on a large flood deposited delta (typical of sand dune areas on former glacial lake deltas further to the north) and the slowly-moving sheets of water may have been responsible for some or all of Nebraska’s loess deposits, although the new paradigm leads to a fundamentally different middle and late Cenozoic regional geologic and glacial history than what workers using the accepted paradigm have described.

Morphotectonics of Mount Rendingan Area Related To the Appearances of Geothermal Surface Manifestations

DOI: 10.17014/ijog.6.3.291-309The researched area is situated at Mount Rendingan and its surrounding area, Lampung Province, the southern part of Sumatra Island. It has a big potential of geothermal resource in line with a unique graben like bowl landform and geothermal surface manifestations. This research was carried out using remote sensing and field observation methods. The remote sensing method used topography and Shuttle Radar Topography Mission -Digital Elevation Model (SRTM-DEM) maps to analyze morphotectonic attributes, and the result was validated by morphotectonic data analysis from field observation. The purpose of this research is to evaluate the relation between morphotectonic and the appearances of geothermal surface manifestations. The interpretation of SRTM-DEM and topographic maps are supported by morphotectonic analyses,which indicate that the geothermal surface manifestations in this area are controlled by tectonic activity. It has various levels of lift which are shown by the values of valley height weight ratio (Vf) from 0.16 to 3.31 and the values of mountain front sinuosity (Smf) from 1.05 to 2.09. The morphotectonic characteristics can describe the geological structure activity levels which are reflected in the landform and its rock. The volcanic areas consist of igneous rocks which have small primary permeabilities. However, the development of geological structure can cause fractures in the rock that step in as a medium for passing geothermal fluid from depth to surface. They are found on the fault intersection zone system trending NE-SW and NW-SE, NNE-SSW and NNW-SSE, and WE system directions that indicate the fault system is correlated with the appearances of geothermal manifestations.

Geomorphological mapping based on DEMs and GIS: A review

Abstract. Geomorphology is a scientific discipline dealing with the characteristics, origin, and evolution of landforms. It utilizes topographic data such as spot height information, contour lines on topographic maps, and DEMs (Digital Elevation Models). Topographic data were traditionally obtained by ground surveying, but introduction of aerial photogrammetry in the early 20th century enabled more efficient data acquisition based on remote sensing. In recent years, active remote sensing methods including airborne and terrestrial laser scanning and applications of satellite radar have also been employed, and aerial photogrammetry has become easier and popular thanks to drones and a new photogrammetric method, SfM (Structure from Motion). The resultant topographic data especially raster DEMs are combined with GIS (Geographic Information Systems) to obtain derivatives such as slope and aspect as well as to conduct efficient geomorphological mapping. Resultant maps can depict various topographic characteristics based on surface height and DEM derivatives, and applications of advanced algorithms and some heuristic reasoning permit semi-automated landform classification. This quantitative approach differs from traditional and more qualitative methods to produce landform classification maps using visual interpretation of analogue aerial photographs and topographic maps as well as field observations.For scientific purposes, landforms need to be classified based on not only shape characteristics but also formation processes and ages. Among them, DEMs only represent shape characteristics, and understanding formation processes and ages usually require other data such as properties of surficial deposits observed in the field. However, numerous geomorphological studies indicate relationships between shapes and forming-processes of landforms, and even ages of landforms affect shapes such as a wider distribution of dissected elements within older landforms. Recent introduction of artificial intelligence in geomorphology including machine learning and deep learning may permit us to better understand the relationships of shapes with processes and ages. Establishing such relationships, however, is still highly challenging, and at this moment most geomorphologists think landform classification maps based on the traditional methods are more usable than those from the DEM-based methods. Nevertheless, researchers of some other fields such as civil engineering more appreciate the DEM-based methods because they can be conducted without deep geomorphological knowledge. Therefore, the methods should be developed for interdisciplinary understanding. This paper reviews and discusses such complex situations of geomorphological mapping today in relation to historical development of methodology.

Topographic Map Interpretation of Bighorn River-Wind River Drainage Divide Located East of Wyoming's Wind River Canyon, USA

Detailed topographic map evidence is used to test the ability of two fundamentally different regional geomorphology paradigms to explain Bighorn-Wind River drainage divide evidence in the Copper and Lysite Mountain areas between Wind River Canyon and the Bighorn Mountains. Identified divide crossings were interpreted to be places where water had once flowed across what is now a major drainage divide. More than 20 such divide crossings were identified and ranged in elevation from 1924 to 2485 meters and could all be linked to north-oriented Bighorn River tributaries and also to south-oriented streams flowing to west-oriented Badwater Creek (a Wind River tributary). Lowest elevation divide crossings were located to the north of both Copper Mountain and Lysite Mountain. An attempt was first made to explain each identified divide crossing or group of divide crossings from the accepted paradigm's perspective, which requires drainage routes to have originated on the surface of a hypothesized Oligocene and Miocene sediment cover that buried the drainage divide area with the drainage routes eroding down through the sediment cover as the drainage divide was exhumed. Next the same evidence was interpreted from a recently proposed paradigm's perspective, which requires massive south- and southeast-oriented floods to have flowed across the Missouri River drainage basin as mountain ranges and plateau areas were being uplifted. The accepted paradigm could not easily explain the large number of observed divide crossings, many divide crossing details, and why geologic maps show few or no hypothesized sediment cover remnants. The new paradigm explained the large number of observed divide crossing and most observed divide crossing details and did not require an Oligocene and Miocene sedimentary cover.

Origin of the Redwater River Drainage Basin Determined by Topographic Map Interpretation: Eastern Montana, USA

Topographic and geologic map interpretation strongly suggests the eastern Montana Redwater River valley eroded headward across large southeast-oriented ice-marginal melt water floods. The north-oriented Redwater River heads in an area to the south of recognized continental glaciation and flows into the recognized glaciated region before joining the east-oriented Missouri River. Detailed topographic maps show the eastern drainage divide is asymmetric with steeper slopes on the Redwater River side and is crossed by shallow dry valleys linking northwest-oriented Redwater River tributaries with southeast-oriented streams that flow as barbed tributaries to the northeast-oriented Yellowstone River. The western drainage divide is also crossed by shallow dry valleys linking northwest-oriented drainage routes to north-oriented Missouri River tributaries with southeast-oriented and barbed tributaries to the northeast- and north-oriented Redwater River. Alluvium from upstream Yellowstone River source areas found within the Redwater River drainage basin suggests the Redwater River and much longer Yellowstone River valleys eroded headward from a continental ice sheet margin as headward erosion of the larger Yellowstone River valley across the southeast-oriented flood flow was supplemented by northeast- and north-oriented flow moving at the present day Redwater-Yellowstone River drainage divide elevation.

Upper Sun River Drainage Basin Origin Determined by Topographic Map Interpretation Techniques: Lewis and Clark and Teton Counties, Montana, USA

A new and fundamentally different regional geomorphology paradigm in which massive south- and southeast-oriented meltwater floods flowed across the entire Missouri River drainage basin is tested by interpreting detailed topographic maps of the Montana upper Sun River drainage basin region by trying to explain origins of previously unexplained or poorly explained erosional landforms located upstream from Sun River Canyon (which cuts across Montana’s north-to-south oriented Sawtooth Range). Mountain passes, through valleys, and other drainage divide low points along what are today high mountain ridges, including the North American east-west continental divide, are interpreted to be evidence of drainage routes that once crossed the region. These drainage divide crossings suggest that prior to erosion of present-day upper Sun River drainage basin valleys, massive floods moved in south directions across what are today the north-oriented Middle and South Fork Flathead River drainage basins into today’s upper Sun River drainage basin area and carved a complex of diverging and converging channels into what was probably a low relief surface now represented by the crests of the region’s highest mountain ridges. Further, the map evidence shows how a diverging complex of south- and southeast-oriented upstream Sun River drainage basin flood flow channels changed flow direction to cross the Sawtooth Range in a northeast direction before converging on the Montana plains at a location downstream from Sun River Canyon. The observed upper Sun River drainage basin area topographic map evidence is consistent with the new geomorphology paradigm predictions, in which massive south-oriented meltwater floods flowing across the rising rim of a continental ice sheet created deep “hole” (created by deep ice sheet erosion and ice sheet weight caused crustal warping) are diverted to flow in northeast and north directions into and across deep “hole” space being opened up by ice sheet melting.

Morphometric analysis of sinkholes using a semi-automatic approach in Zhijin County, China

Efficient detection and analysis of natural sinkholes is essential for human sustainability in karst area. In this work, two methodologies were applied to detect and quantify natural sinkholes in southwest China, using of DEMs derived from ASTER and SRTM remote sensing images and topographic maps. The methodologies were a semi-automatic approach and a field-based approach. The first identifies the sinkholes based on DEM. The latter integrates the field survey, visual interpretation of high-resolution aerial photographs and topographic maps. The comparison between the semi-automatic approach and field-based approach generated the threshold values of the sinkhole shape, area, and TPI (topographic position index), which were used to distinguish true sinkholes and improve the identification accuracy. The result indicated that the semi-automatic approach produced the best accuracy by using the thresholds area > 60 m2, ellipticity > 0.2, and TPI ≤ 0 with the DEM from the topographic maps. With these realistic thresholds, the semi-automatic model shows well performance that model accuracy ranges from 0.78 to 0.95 for DEM resolutions from 3 to 75 m. The morphometric analysis was then obtained by using parameters derived from the semi-automatic approach and field-based approach. The sinkhole morphometric parameters are area, perimeter, diameter, shape, orientation, and volume. The results demonstrate (1) morphometric characteristics of sinkholes derived from the semi-automatic approach are coincident with those from the field-based approach. (2) Sinkholes in the region are relatively old and skewed to irregular or elliptical shape. (3) Sinkhole diameter and spatial alignments are highly controlled by faults. (4) Sinkholes argue about solution-only origin in the region.

Belle Fourche River-Cheyenne River Drainage Divide Area in the Wyoming Powder River Basin Analyzed by Topographic Map Interpretation Methods, USA

The dearth of scientific literature in which specific erosional landform origins are determined is an example of what Thomas Kuhn considered a scientific crisis. Scientific crises arise when scientists following their discipline’s established paradigm’s rules, or doing what Kuhn calls normal science, cannot explain observed evidence. Scientific crises are resolved in one of three ways. Normal science may eventually explain the evidence and normal science returns, the unsolved problems may be identified and labeled and left for future scientists to solve, or a new paradigm may emerge with an ensuing battle over its acceptance. To succeed any new paradigm must demonstrate its ability to explain the previously unexplained evidence and also open up new research opportunities. During the 20th century’s first half regional geomorphologists abiding by their discipline’s paradigm rules unsuccessfully tried to explain origins of numerous erosional landforms, such as drainage divides and erosional escarpments. Their failures eventually caused the regional geomorphology discipline, at least that part of the discipline concerned with determining specific erosional landform origins, to almost completely disappear. A new and fundamentally different geomorphology paradigm that requires massive southeast-oriented continental ice sheet melt-water floods to have flowed across the Powder River Basin has the ability to explain specific erosional landform origins and is demonstrated here by using detailed topographic map evidence to show how large southeast-oriented floods eroded the Powder River Basin’s Belle Fourche River-Cheyenne River drainage divide segment, eroded through valleys now crossing that drainage divide segment, eroded the Powder River Basin’s Belle Fourche River valley, established Belle Fourche and Cheyenne River Powder River Basin tributary valley orientations, and eroded the north-facing Pine Ridge Escarpment. The success of this and other similar new paradigm demonstrations suggest many if not all specific erosional landform origins can be determined.

Topographic map analysis to determine Arjuno-Welirang volcanostratigraphy and implication for geothermal exploration

Volcanostratigraphy study is used for supporting geothermal exploration on preliminary survey. This study is important to identify volcanic eruption center which shows potential area of geothermal heat source. The purpose of volcanostratigraphy study in research area is going to distinguish the characteristics of volcanic eruption product that construct the volcanic body. The analysis of Arjuno-Welirang volcanostratigraphy identification are based on topographic maps of Malang sheet with 1:100.000 scale, 1:50.000 scale, and a geological map. Regarding to the delineation of ridge and river, we determine five crowns, three hummocks, one brigade and one super brigade. The crowns consist of Ringgit, Welirang, Arjuno, Kawi, and Penanggungan, the hummocks comprise of Kembar III, Kembar II, and Kembar I, the brigade is Arjuno-Welirang, and the super brigade is Tengger. Based on topographic map interpretation and geothermal prospect evaluation method analysis, shows that Arjuno-Welirang prospect area have good geothermal resource potential.

Snow-avalanche impact craters in southern Norway: Their morphology and dynamics compared with small terrestrial meteorite craters

This regional inventory and study of a globally uncommon landform type reveals similarities in form and process between craters produced by snow-avalanche and meteorite impacts. Fifty-two snow-avalanche impact craters (mean diameter 85m, range 10–185m) were investigated through field research, aerial photographic interpretation and analysis of topographic maps. The craters are sited on valley bottoms or lake margins at the foot of steep avalanche paths (α=28–59°), generally with an easterly aspect, where the slope of the final 200m of the avalanche path (β) typically exceeds ~15°. Crater diameter correlates with the area of the avalanche start zone, which points to snow-avalanche volume as the main control on crater size. Proximal erosional scars (‘blast zones’) up to 40m high indicate up-range ejection of material from the crater, assisted by air-launch of the avalanches and impulse waves generated by their impact into water-filled craters. Formation of distal mounds up to 12m high of variable shape is favoured by more dispersed down-range deposition of ejecta. Key to the development of snow-avalanche impact craters is the repeated occurrence of topographically-focused snow avalanches that impact with a steep angle on unconsolidated sediment. Secondary craters or pits, a few metres in diameter, are attributed to the impact of individual boulders or smaller bodies of snow ejected from the main avalanche. The process of crater formation by low-density, low-velocity, large-volume snow flows occurring as multiple events is broadly comparable with cratering by single-event, high-density, high-velocity, small-volume projectiles such as small meteorites. Simple comparative modelling of snow-avalanche events associated with a crater of average size (diameter 85m) indicates that the kinetic energy of a single snow-avalanche impact event is two orders of magnitude less than that of a single meteorite-impact event capable of producing a crater of similar size, which is consistent with the incremental development of snow-avalanche impact craters through the Holocene.

Comparative Research of Visual Interpretation of Aerial Images and Topographic Maps for Unskilled Users: Searching for Objects Important for Decision-Making in Crisis Situations

The article presents the results of research focused on the speed and success rate of reading aerial images and topographic maps showing the same territory in the Czech Republic. Attention was focused on searching for objects of importance in terms of disaster management (railway and road bridges, road, watercourse, railway station, airport). The success rate was electronically evaluated by the Hypothesis software as a whole for the image, and the map was created for all respondents and for selected groups of respondents. The results showed that, with the exception of watercourse identification, other strategic objects are found faster and more reliably on color aerial images. No differences in speed and success of interpretation were found between men and women, laymen and experts. Soldiers and crisis management personnel were faster than laymen, but they were equally successful. Color aerial images or color aerial orthophotomaps have thus proved to be a key source of data for effective decision-making on a territory where a crisis event is taking place and where the deployment of a crisis unit is a need.

Landslide characterization and distribution in northern Ethiopia: a case study from the Adishu area

Landslides have resulted in large numbers of casualties and huge economic losses in the hilly and mountainous areas of the Ethiopian highlands. Adishu (Adi-Quchi and Quilet villages in particular) is one of the areas most highly affected by rainfall-driven landslides. Field investigations of this area have revealed displacement of 204 people, destruction of 56 rural houses and 5 km of rural roads, and effects on 58 ha of agricultural land due to landslides. In addition, a significant proportion of the population still lives in a terrain potentially endangered by landslides. The geology of the study area consists of Antalo limestone, Agula shale, Amba-Aradom sandstone, basalt flows, and unconsolidated sediments. Thirteen major landslides with clear downthrown head scarps and downspread toes were identified. Inventory of landslides was based on the interpretation of aerial photographs, topographic maps, satellite images, and field identifications, with the aim to assess the cause and type of landslides in the study area. The different methods applied to soils and rocks included the direct shear test, Schmidt hammer, and inverse auger hole methods. The results revealed that soil materials in the area have a low permeability (1.22 × 10−6–3.13 × 10−6 m/s), a high plasticity index (17.2–29.4), and cohesion values ranging between 10 and 26 kN/m2. Soil samples from the stable in situ layers showed relatively high cohesion and relatively small internal angle of friction compared to the residual layer. The common types of landslides in the study area were rock falls, rock topples, debris/earth flows, and debris/earth slides accompanied by translational and rotational sliding mechanisms. These landslides could be classified into three zones based on location, type of failure, mode of failure, and direction of failure. The upper layers of basalt and limestone rocks showed significant percolation and recharge to the downslope layer (marl-shale). We therefore concluded that the marl-shale layer is mainly responsible for sliding, whereby percolated and recharged water cause saturation and the development of pore water pressure in this layer due to its imperious nature. The Qulate (landslide zone one and zone two) and Adi-Quchi (landslide zone three) localities are highly affected areas where there are unconsolidated soil deposits underlain by marl-shale along the streams due to removal of underlying and lateral support by gully erosion.

Using topographic map interpretation methods to determine Tookany (Tacony) Creek erosion history upstream from Philadelphia, Pennsylvania, USA

Topographic map interpretation methods are used to determine erosional landform origins in and adjacent to the Tookany (Tacony) Creek drainage basin, located upstream from and adjacent to Philadelphia, PA. Five wind gaps notched into the Tookany-Wissahickon Creek drainage divide (which is also the Delaware-Schuylkill River drainage divide), a deep through valley crossing the Tookany-Pennypack Creek drainage divide, a Tookany Creek elbow of capture, orientations of Tookany Creek tributary valleys, a narrow valley carved in erosion resistant metamorphic bedrock, and the relationship of a major Tookany Creek direction change with a Pennypack Creek elbow of capture and a Pennypack Creek barbed tributary are used along with other evidence to reconstruct how a deep south oriented Tookany Creek valley eroded headward across massive southwest oriented flood flow. The flood flow origin cannot be determined from Tookany Creek drainage basin evidence, but may have been derived from a melting continental ice sheet, and originally flowed across the Tookany Creek drainage basin region on a low gradient topographic surface equivalent in elevation to or higher than the highest present day Tookany Creek drainage divide elevations with the water flowing in a complex of shallow diverging and converging channels that had formed by scouring of less resistant bedrock units and zones. William Morris Davis, sometimes referred to as the father of North American geomorphology, spent much of his boyhood and several years as a young man living in the Tookany Creek drainage basin and all landforms discussed here were within walking distance of his home and can be identified on a topographic map published while he was developing and promoting his erosion cycle ideas. Davis never published about Tookany Creek drainage basin erosion history, but he developed and promoted uniformitarian and erosion cycle models that failed to recognize the significance of Tookany Creek drainage basin erosional landform features providing evidence of the immense floods that once crossed present day drainage divides and eroded the Tookany Creek drainage basin.

Automated delineation of karst sinkholes from LiDAR-derived digital elevation models

Sinkhole mapping is critical for understanding hydrological processes and mitigating geological hazards in karst landscapes. Current methods for identifying sinkholes are primarily based on visual interpretation of low-resolution topographic maps and aerial photographs with subsequent field verification, which is labor-intensive and time-consuming. The increasing availability of high-resolution LiDAR-derived digital elevation data allows for an entirely new level of detailed delineation and analyses of small-scale geomorphologic features and landscape structures at fine scales. In this paper, we present a localized contour tree method for automated extraction of sinkholes in karst landscapes. One significant advantage of our automated approach for sinkhole extraction is that it may reduce inconsistencies and alleviate repeatability concerns associated with visual interpretation methods. In addition, the proposed method has contributed to improving the sinkhole inventory in several ways: (1) detection of non-inventoried sinkholes; (2) identification of previously inventoried sinkholes that have been filled; (3) delineation of sinkhole boundaries; and (4) characterization of sinkhole morphometric properties. We applied the method to Fillmore County in southeastern Minnesota, USA, and identified three times as many sinkholes as the existing database for the same area. The results suggest that previous visual interpretation method might significantly underestimate the number of potential sinkholes in the region. Our method holds great potential for creating and updating sinkhole inventory databases at a regional scale in a timely manner.

Design and implementation of an expert system for updating thematic maps using satellite imagery (case study: changes of Lake Urmia)

Thematic maps are fundamental for decision-making in natural resources and ecosystem management and planning. Thematic information, land cover in particular, is dynamic and changeable with the passage of time. Hence, providing up-to-date and precise data in a short period of time is considered as a key factor for successful utilization of these maps. Field inspection and visual interpretation of satellite images and topographic maps are necessary for this purpose. These processes are labor intensive, time consuming, and costly. An expert system, as a computer system with the capability of an expert’s performance simulation, could be an assistant for experts involved with the thematic map updating process. In this paper, a knowledge-based expert (KBE) system was designed, implemented, and tested to automate, facilitate, and expedite the conventional thematic map updating procedure. The developed system in this research is based on using existing thematic map and satellite images together with the new acquired satellite image of the desired region. It entails the following five major steps: (1) relative radiometric normalization, (2) change detection, (3) spectral database construction, (4) identifying the content of the changes, and (5) cartographic operations. In order to assess the effectiveness of the proposed KBE system for automatic updating of thematic maps, two different case studies related to Urmia Lake and surrounding areas were considered. Near-anniversary bi-temporal Landsat TM 4,5 imagery, acquired on 30 June 1989 and 24 June 2007 over the eastern coast of the lake alongside the existing land cover map of 1989, were used in the first case study. Utilized data sets in the second case study were near-anniversary Landsat 8 satellite images (OLI sensor) taken on 20/7/2014 and 23/7/2015 over the southern coast of lake alongside the outdated land cover map of interest region in 2014. Test results of different parts of the system were confirmed by the experts, and finally the system could satisfy the assessment criteria from the experts’ point of view in this particular application. Overall accuracy of the updated thematic map in the first and second case studies was 97.18 and 87.81 %, respectively.

Landslide susceptibility assessment at Wadi Jawrah Basin, Jizan region, Saudi Arabia using two bivariate models in GIS

This paper presents an evaluation of two bivariate statistical approaches, frequency ratio (FR) and weights-of-evidence (WoE) for landslide susceptibility mapping (LSM) at south-western part of Saudi Arabia, Jizan region. Landslide locations were identified and mapped from interpretation of high resolution satellite images (GeoEye 0.5 m and QuikeBird 0.6m), topographic maps (scale of 1:10,000), historical records, and extensive field surveys. A total of 106 landslide locations were mapped using Arc-GIS software and divided into two groups, 75% and 25% of landslide locations were used for training and validation of models, respectively. Eleven landslide conditioning factors such as elevation, slope, curvature, aspect, lithology, topographic wetness index (TWI), normalized difference vegetation index (NDVI), proximity to lineament, roads and rivers were considered in this evaluation. The effects of these factors on landslide occurrence were assessed using aforementioned bivariate statistical approaches. For validation, the models results were compared with landslide locations which were not used during the models building. Subsequently, the receiver operating characteristic (ROC) curves were established and area under the curves (AUC) was calculated for the landslide susceptibility maps using the success (training data) and prediction (validation data) rates. The results showed that the area under the curve for success rates are 0.861 (86.1%) and 0.839 (83.9%) and for prediction rates are 0.796 (79.6%) and 0.791 (79.1%), respectively for frequency ratio and weight-of-evidence models. The resulting landslide susceptibility maps showed five classes of susceptibility such as very high, high, moderate, low, and very low. The percentage of existing training and validating landslides data in high and very high zones of the susceptibility maps were calculated to be 90.02% and 76.03% for frequency ratio model and 88.33% and 79.3% for weight-of-evidence model, respectively. The results revealed that the frequency ratio and weights-of-evidence models produced reasonable accuracy. The resultant maps would be useful and can also help planners for general choosing favorable locations for development schemes, such as infrastructural, buildings, road constructions, and environmental protection.

Natural and human impact on the land use and soil properties of the Sikkim Himalayas piedmont in India

Natural and human causes of change in land use and soil properties were studied in the Sikkim Himalayas piedmont over the last 150 years, with a special emphasis on the period 1930–2010. Analysis of historical reports, combined with the visual interpretation of topographic maps and satellite images, indicates that the land reforms related to the location of tea gardens caused rapid deforestation of the higher elevated terraces in the late 19th century. Continuous population growth between 1930 and 2010 caused a shift in the major land use changes from the terraces to the floodplains. As a consequence, a gradual extension of tea plantation and forestry development helped in stabilizing the land use of the terraces, while the parallel deforestation of mountain catchments and floodplains for rice cultivation intensified fluvial activity. The enlargement of river-channel area by about 42% between 1930 and 2010 excluded a large part of the floodplains from cultivation and increased risk of soil degradation. The replacement of natural forest by monocultural tea and rice cultivation influenced the physical and chemical properties of the soil. Statistically significant changes were observed only in some chemical properties of the topsoil. Tea cultivation reduced the total carbon content by 26% and total nitrogen content by 33% in the surface soil horizon. The influence of rice tillage on the soil properties is masked by the fluvial activity. The combined effect of flooding and rice cultivation is reflected in the lower content of total carbon and nitrogen in the surface of the soil, namely, 76% and 77% respectively. Taking into account the long-term nature of the plantation, the soil still has the capability to support tea production. The productivity of rice depends partly on fertilization levels and partly on the natural deposition of fresh sediment eroded from mountains.

The recent tectonics of the Caspian Sea region

Recent uplifts and depressions complicated by lineaments, many of which are faults, were found within the Caspian depression using complex structural and geomorphological studies, which included visual interpretation of different-scale topographic maps, as well as an analysis and computer processing of radar satellite images. In many respects, the latest dislocations correlate with the structures and sedimentary cover of the basement and are also determined by salt tectonics. Their formation is substantially influenced by the Ural Orogen and the Scythian plate is involved in the entire uplift at the latest stage.