Journal of RS and GIS for Natural Resources
Year:2012 | Volume:3 | Issue:2|Papers Count:10

Astragalus gossypinus Fischer is one of the most important range plants in west region of Isfahan, which is very critical for soil conservation and people’s economic life. Nevertheless, the grazing pressure and overuses cause habitat destruction. This study has been done for determination of its potential habitat in Lenjan and Flavarjan parishes of Isfahan province. To achieve this purpose, spatial data of this specie’s presence used as suitable places for its growth and the environmental condition (Climate, Soil & Physiographic) used for recognition of its habitat’s necessities. Soil data turned to soil maps using antecedent studies and interpolating soil profile points. Climatic and physiographical data have been prepared as well and got ready to be imported to the ultimate model. By importing the information layers in ENFA model and using harmonic mean analysis in Biomapper software; the map of Astragalus gossypinus potential habitat has been created. The results show that gravel percentage, soil potassium, saturated moisture, electrical conductivity and annual precipitation are the most important factors in habitat choosing by Astragalus gossypinus in study area. 25300 hectares of the study site are potential habitat of Astragalus gossypinus which is 16 percent of the study site. To evaluate the verity of this model, Boyce’s index has been used and model rectitude in this test was determined 85.2 percent.

The study area is located in southeast Khorramabad in Lorestan province and based on classification of tectonic and old watersheds in Iran, is in folded Zagros range. According to the type of geological formations, seismic, climatic and topographic conditions, this area is considered unstable slip. Landslide is considered one of the most dangerous types of natural disasters. This phenomenon is causing great damage in many countries all years that need to contemplate measures to reduce these losses. This study is carried out to evaluate the remote sensing data for landslide cognition and mapping them. The confusion matrix has been used for data accuracy assessment of TM, ETM+, IRS, ASTER images. The separation of landslide zones done with using the detection techniques, visually making the different color compositions and finally these results used for comparison with real situations. Calculate the confusion matrix for maps show that by increasing the spatial resolution images, diagnostic accuracy of occurred landslides increase.

The increasing number of sensor type for terrestrial remote sensing has necessitated supplementary efforts to evaluate and standardize data from the different available sensors. Accurate and up-to-date global land cover data sets are necessary for various global change research studies including climatic change, biodiversity conservation, ecosystem assessment, and environmental modeling. Therefore using of data numeral product of sensor with different resolution and spectral bands, can different data for evaluation and range management for users generate. The aim of the present research was: Comparison maps vegetation production of sensors IRS-WiFS and MODIS on Semirom region. Various preprocessing, including geometric correction were applied using topographic maps of 1:250000 with a RMSe 0.8 pixel for sensor MODIS and RMSe 0.35 pixel for sensor IRS-WiFS. The atmospheric and topographic corrections were applied using subtraction of dark objects method and the Lambert method accordingly. Image processing including FCC, PCA, vegetation indices and supervised classification were employed to produce the vegetation canopy map. Field data collection was started on June 2005 on 800, 000 ha. Various vegetation types were sampled using stratified random sampling method. 20 random sampling points were selected and the percent cover was estimated. MODIS data sets and IRS-WiFS data sets were used for this study. Digital data and the indices maps were used as independent data and the field data as dependent variables. The resulted models were processed on and the resulted images were categorized in 5 classes. The results confirmed the high correlations of used WiFS indices with field data. Also the NDVI, SAVI indices which employ RED and NIR bands had relatively highly correlations with pasture data. Finally the produced maps were controlled for their accuracies. Result showed maps land cover produced with IRS-WiFS data set have very high accuracy land cover produced with MODIS data set.

In this study environmental assessment of Kalat corridor and surrounding area was considering by using functional zoning techniques. For this purpose eight macro information layers in the area include climate, Topography, geology, soil, hydrology, ecology, natural hazards and land use information layers were identified. Then twenty extracted micro variable were plotted as effective factors on formation of functional zoning. Then these variables classified based on their sub classes. At the first level, the variables were weighted with approach of multi criteria evaluation and then the classes were valued by using Boolean logic (zero and 1). Finally with combining the variables weights and classes values the layers overlayed in GIS. The result of functional zoning indicate that 41.7% of total the study area have adequate environmental capacity for tourism development in combining with other activates and 34.8% of total area particular in highland have adequate capacity for ecotourism and extensive promenade. Also functional zoning was determined and three differentiation environment zones defined in corridor and general landscape of truism development in this area illustrated.

Landscape includes a mosaic of landscape elements in a context of a major land use/cover. Much emphasis has been placed on developing methods to quantify landscape patterns in recent years. Landscape elements include various types, including urban areas and patches, which were used for change’s identification in the current study. Any urban area has been considered a landscape patch and their patterns for the Gorgan city between the years 1987 and 2001 have been compared in this study. Number, shape and neighborhood metrics was the major groups of metrics calculated. To do so, urban areas were fed to Fargstats® Software as patches. Comparison showed that development pattern in Gorgan city has led to the creation of larger and simpler patches with and less fractal dimension during the 14-years period of our study. In fact, urban growth was shown to be adhering to the previous urban patches. This is also visible to the spatial investigation of the largest patches (a complex of continues areas), such that, for example, two large patches in 1987 had been joined because of infill. Despite the tendency of urban growth around previous urban patches and in their vicinity, patches did not show a uniform distribution in the area, rather, they were irregular. This result is confirmed by the fact that the urban area has increased 2.1 times during the study period.

There are two aspects for human utilization of the land, land management and kind of utilization. Evaluation of ecological capability is used for optimal utilization of soil and water resources and investigation of the environmental consequences. In this study, evaluation of ecological capability of Ivar watershed, located in north Khorasan province, investigated with using maps overlay method. The ecological unite and land use planning maps of Ivar watershed was formed from the combining aspect, slope, elevation, soil, vegetation type and plant density maps and considering climatic characteristics, socio-economic conditions and water resources. The results showed that 64.95% of the area was in class of 2 of rangeland, 24.36% and 6.58% in class 1 and 2 of conservation respectively, 1.55% in class of 2 of agriculture, 2.56% in class of 2 of rural development ecological capabilities. Comparing land use planning and current land use maps showed that 65.2% of the watershed areas have suitable land uses and 34.8% of the watershed area needs to replace landuse.

Selecting an appropriate sample size is quite important to achieve acceptable accuracy in evaluating vast natural areas with field and remote sensing methods. This study aimed to evaluate the effect of different sample sizes on the correlation of vegetation cover and remote sensing based indices such as NDVI in three rangeland types, Semirom-Isfahan. Landsat5 (TM sensor) and IRS-P6 (AWiFS sensor) satellite images were used to conduct this research. The percentage of vegetation and ground cover components including canopy cover, litter, rock, gravel, stone and bare soil were determined using step-point method in 4 radial direction in 30, 50, 100 and 150 meters (1200, 2000, 4000 and 6000 points per rangeland type). In other words, the ground cover and NDVI indices correlations were compared in 2826, 7850, 31400 and 70650 square meters using the satellite images. NDVI indices were calculated in all vegetation types and correlated with different components of ground cover. According to results, TM sensor data had more appropriate correlation than AWiFS sensor with field vegetation cover in all studied sample sizes. Vegetation cover and NDVI correlations were decreased in degraded vegetation types with increasing ground heterogeneity. For example, the correlation was not significant (p<0.05) in all studied sample sizes in degraded Astragalus spp-Scariola orientalis vegetation type, while the highest correlation was obtained (77%) in 7850 square meters sample size in more homogeneous Bromus tomentellus vegetation type.

Babolrood basin located in Mazandaran province is one of the areas that in recent years, with rapid population growth and development of residential areas has faced. Development of residential areas regardless of land capability for development caused significant side effects such as environmental degradation. Therefore, it is essential that land capability for residential developing by appropriate methods is evaluated and then the land can planned. With consider to importance of subject, in this study ecological potential for residential areas development in Babolrood basin was evaluated and for this purpose, the Analytical Hierarchy Process (AHP) and GIS was used. For this purpose, in first, Criteria and indicators were selected and relative weights were assigned using expert’s judgment and indicators were mapped at GIS environment. In final, ecological capability map for residential areas development was created with composition of maps and relative weights. The results showed respectively 1.78, 5.82, 11.64 and 38.3 percent of the area has the excellent, good, mediocre and week class capability and 42.44 percent of the area hadn’t capability. Results of this research help to planners to pitch and development of residential areas.