GEOGRAPHICAL DATA
Year:2015 | Volume:23 | Issue:92|Papers Count:8

Wayfinding is one of the important tasks of individuals in an urban traffic network. Guider geospatial information systems are the common services which helps people to navigate different unfamiliar routes with altered goals. The key challenge of these systems is the introduction of wayfinding information in a context-aware manner. However, space, time and identity are the primary contexts and the other contexts are modeled based on these three elements. This article concentrated on modeling spatio-temporal relevancy of moving user based on his/her identity. The introduced model is able to cover all of the spatial relationships (topologic, metric and directional) on temporal dimension also to consider the characteristics of user and related contexts. In this way the proposed model utilizes Allen’s Multi- Interval Algebra (MIA) along with Dynamic Voronoi continuous Range Query (VCRQ) and introduces an innovative approach based on coarser calculus principals and customization methods. The model (MIA25) has been implemented as a software runnable on mobile systems and PDAs. The assessment of the implemented model is done regarding to three parameters including accuracy, time performance and users satisfaction. Tehran Districts 3, 6 and 11 are selected as case study area. In order to test the accuracy parameters, the designed software is run in three different routes with two different velocities and three time durations in 100 iterations. Then the accuracy of the detection of the related contexts is tested by means of a binomial distribution with one-sided 95% confidence level, precision and recall factors. The results of implementation and evolution based on accuracy, time performance and user satisfaction demonstrated the efficiency of the proposed model in an urban context-aware wayfinding systems.

Knowledge of qualitative and quantitative characteristics of changes are extremely important in environmental planning, land use planning and sustainable development. Currently using vegetation maps is one of the key factors in data making for macro and micro planning. In this study, information of Landsat ETM + and OLI were used to display the time and location changes of vegetation in Behbahan city in 1378 and 1392 and calculated the NDVI index for this two years. In order to evaluate the quality changes of vegetation, the numerical values of the index was classified the 4 classes lush vegetation including of land with excellent coverage, very good coverage, good and poor coverage. Then, the changes were determined using CROSSTAB. The results showed qualitative and quantitative changes in vegetation for the study area has been extensive over 14 years, so that, the lands had excellent, good and poor coverage, their area were increased and land area which had good coverage, were decrease. The greatest increase in land area has been occurred with excellent coverage, so that, it had increased from 5069.76 in 1378 to 7735.5 hactar in 1392. Also, the most reduction in land area has been occurred with good coverage, which reached from 34061.4 hactar to 27434.43 hactar. Finally, regression equation was obtained to show better relationship between the two parameters of vegetation and temperature. These results is confirmed that vegetated has a lower temperature and this surface has the cooling effects on surrounding. Therefore, the destruction of vegetation will follow the warming of city surface and environmental consequences.

One type of environmental hazards in many areas in our country that causes destroying agricultural lands, rangeland and Infrastructure is gully erosion. In this study, fuzzy logic operators are used to determine the different hazard zones, obtain the area of each of them and gully erosion hazard map in Troud watershed. To achieve this objective, satellite imagery, aerial photo interpretation with scale of 1:20000, topographic maps with scale of 1:50000, geological maps with scale of 1:100000, field studies and ArcGIS software has been used as research tools. For this purpose, at first a few effective variables that have important role in the formation and development of gully erosion and gully erosion areas were identified. The next step, Effective factors classes were weighted And Gully erosion maps were prepared using fuzzy operators including fuzzy Algebraic sum, fuzzy product, fuzzy gamma0.5 and fuzzy gamma 0.8 in GIS environment. The results indicated that, in fuzzy Algebraic sum method was located 100% of the gully in high zone. 83.29% of the gullies have occurred in low zone in fuzzy product. According to the results obtained, 60.93% of the gullies were located in low zone and 17 % of gullies have occurred in high and very high zones in method fuzzy gamma 0.5. In fuzzy gamma 0.8 method, were located 1.5% of the gullies in low zone and 62% of the gullies in high and very high zones.

With the increase in urbanization, the surface of earth and its climate have been changed. These changes resulted in more frequent inundation problems in urban areas. Prediction and monitoring systems can act as an appropriate tool for quick decision making and take necessary actions to deal with inundation in urban areas. In this study, we developed a WebGIS system for the prediction and monitoring storm inundation in urban areas. This system is based on service oriented architecture and uses web processing services. The architecture of developed system has three tiers. They are data tier, business logic tier and presentation tier. Data tier includes some data which stored as spatial web services in a distributed database. Business logic tier includes two web processing services. These web processing services are hydrological characteristics calculation service and inundation calculation service. Hydrological characteristics calculation service uses WASI algorithm to calculate flow direction as well as flow accumulation. The output of hydrological characteristics calculation service is delivered to inundation calculation service as input. Inundation calculation service uses ASIISM model for inundation calculations. The output of this service is inundated points with inundation volume, inundation area and its depth. A central web processing service chain these services. The duty of presentation tier is to take precipitation information from user and show resulting maps. A part of region 22 in Tehran was chosen as case study area. The results showed that sum of inundation area for selected storm event is about 0.81 percent of study area. The system used by users and its user interface, its inundation simulation ability and its ability of inundation evaluation were evaluated by these users. Its user interface and its ability of inundation simulation have the most and the least satisfaction among users. Using standard based spatial web services to implement the system, provided reusable services.

Landform is a complication of land or landscape the establishment of which is formed by natural processes that can be described and defined by diagnosis index and if detected, the Landform information about their structure and composition, texture or its integrated offers. Landform variety and diversity of participants, mainly by changing the shape and position of the controls placed. So, classify and identify different areas according to their morphologic characteristics is essential. This study attempts to classify different Landform in the southern city of Darab. This research is Descriptive - analysis based on quantitative methods, field and modeling software Where the TPI method were used for the identification and classification of Landforms the study area. The model input data, including slope, curvature width, curvature minimum and maximum curvatures. The results of the study showed that the morphological classification of the study area includes 10 Landform (stream, mid-stream valleys, drainage, high, u-shaped valleys, plains, small, open slopes, steep upper edge high, middle edge of the slope, the high ridge, mountain). Most of Landform in the region of the water courses (32/19 %) and then peaks are (25.36 %).

Analysis changes in characteristics of daily precipitation is important in water resources planning and planting patterns. In this research, the changes most fitting frequency distribution and its parameters over time were examined. For this purpose, we used daily precipitation data gridded precipitation APHRODITE database 0.25*0.25 degree longitude/ latitude in the Middle East. Daily precipitation data from this database within time interval of 22.03.1951 –20.03.2007 (equals 20453 days) was extracted with Grads software. To track changes over time, the data was divided into two periods of 28 years. First period from 22.03.1951 to 20.03.1979 Precipitation data were inserted in an array with dimensions of 10226*2491 and the second period from 21.03.1979 to 20.03.2007data in an array with dimensions of 10227*2491(days on rows and pixels on columns). For fitting the frequency distribution the Kolmogorov-Smirnov test were applied. With Scripting by Matlab software were fitted distribution functions in normal and gamma type of each pixel with precipitation. Only gamma and exponential distributions were statistically able to obtain the conditions required for the test as the most suitably fitted distribution in Level of confidence 95%. Changes in the spatial and temporal frequency distribution precipitation it is not confirmed as one of the components of climate change tracking. The most fitting indicates calculated using linear momentum distribution indicates slight changes in the spatial distribution pattern of these parameters. But this change does not follow a specific pattern. The standard deviation indicates the parameter mapping in most area of central Iran and the West in recent decades has reduced confidence in the precipitation.

In this research using field data of temperature, salinity and density at stations near the Caspian Sea, South West, to be related two cruises has been study the large-scale currents. Geostrophic current caused balance due to the pressure gradient force and Coriolis force and is a major factor in the development of large scale currents. After analyzing data, the speed and direction of these currents were calculated using satellite images. Aviso satellite images with spatial resolution 0.25o was obtained. Calculations for five vertical sections in the West South Caspian Sea was performed using Excel software. The depth profile of Geostrophic currents in each of these sections was obtained. In South-West Caspian region, the mean velocity of the currents by field data in summer 5.85 cm /s, and in winter 15 cm /s is calculated. The direction of these currents averaging 285 degrees in summer and 44 degrees in the winter to be obtain. Currents counterclockwise in the summer, according to satellite images to speeds 4.5 cm/s, in winter eastern and counterclockwise currents with speeds up to 8 cm/s has been shown. Current speed (the magnitude of the vectors) indicates that the flow rate is more moderate in winter, the reason can be difference in density due to increased river flows (especially the Volga), precipitation, wind, and the result will be noted.

Importance of location reference information in all matters civil and research uncovered. Among the methods for the production of spatial data, photogrammetry method by quickly, economically and, above all, the need to direct the human factors in place, the place is unique. The photogrammetric method, based on observation platforms, as the primary means of providing input data and the operating ring key role in the success and achievements in other areas of play. Today, technological progress leads to high-quality digital camera that promises to provide a location for the camera photogrammetric method with accuracy, speed and efficiency are high. According to the key role that digital aerial cameras in modern photogrammetry, ensure the accuracy of the camera as a prerequisite for ensuring that spatial data will be obtained. In other words, any technical weaknesses in the use of aerial digital cameras lead to inaccurate and unreliable location information that may be the wrong decision by the beneficiaries it is. Due to high costs and administrative difficulties in calibration laboratories, as one of the solutions to the equations self-calibration useful in this context is known. For this purpose, the term optimal Fourier equation of the proposed genetic algorithm based on simulated data were compared with previous models. Based on the results, the model is able to multiple aberrations with minimal dependence on the model. Precision modeling of multiple aberrations in digital camera images simulated Ultra Cam compared to other modeling parameters added to improve the accuracy of approximately 30%, with minimal dependence on the show.