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1.
Tugba Memisoglu Baykal 《Transactions in GIS》2023,27(5):1289-1317
Forests are essential in contributing to the continuity of the natural balance. Therefore, their protection and sustainability are vital. However, all over the world, forest fires occur, and forests are destroyed due to both human factors and unknown causes. It is necessary to carry out studies to prevent this destruction. At this point, GIS-based location–time relationship-based hot spot clustering analysis can provide significant advantages in detecting risky spots of forest fires. In this study, GIS-based emerging hot spot clustering analysis was carried out to determine the risky areas where forest fires will occur and to carry out preventive studies in the relevant areas. Turkey was chosen as the pilot region, and analyses were carried out using the data obtained from the official statistics of the Ministry of Agriculture and Forestry General Directorate of Forestry according to the causes of the fires (negligence, intentional, accidental, unknown cause and natural) between the years 2010 and 2020. Spatial autocorrelation analysis was conducted for each fire type, and threshold distances were determined {with a number of distance bands = 20,000, distant increment = 10,000}. Emerging hot spot analyses were then conducted, and the results were presented as maps and statistical outputs. According to all fire types, 15 new hot spots, 14 persistent hot spots, 33 sporadic hot spots, 9 consecutive hot spots, 15 intensifying, and 2 diminishing hot spot regions were obtained throughout the country. 相似文献
2.
Several models simulate watershed areas by delineating hillslopes. Hillslope size depends on the length of stream tributaries, which are affected by the drainage area threshold (DAT). There is no universal approach to identify the appropriate DAT. Therefore, a method to derive the DAT and a series of steps to delineate a watershed into smaller sizes were proposed in this study, and the impact of hillslope size on slope gradient estimation was investigated. The DAT obtained in this study was smaller than that obtained using other methods, resulting in a shorter length of the tributaries. Dividing these tributaries into equal short segments and using them to delineate the study area reduced the size of the hillslope. The results revealed that the shorter the length of the tributaries, the smaller the hillslope size. The accuracy of gradient estimation increased when the size of the hillslope was reduced. 相似文献
3.
土地利用/覆被变化对细河流域的水文过程影响显著。为研究不同土地利用/覆被情景对流域水文要素的影响情况,本文构建了适用于细河流域的SWAT分布式水文模型,并拟算出不同情景下的流域多年平均月径流量、多年平均地表径流深度、多年平均蒸发量以及多年平均土壤侧流。模拟结果显示:当流域农林用地增加时,平均月径流量增加了8.40%;当建设用地增加时,平均月径流量减少了4.11%;当旱地及其他未利用地增加时,平均月径流量减少了1.93%。综上所述,细河流域农林用地变化对径流产量的影响相对最大,其增加导致径流量增加;旱地及其他未利用对径流产量的影响相对最小,建设用地和旱地及其他未利用地的增加导致径流量减少。 相似文献
4.
Rapid urbanization threatens urban green spaces and vegetation, demonstrated by a decrease in connectivity and higher levels of fragmentation. Understanding historic spatial and temporal patterns of such fragmentation is important for habitat and biological conservation, ecosystem management and urban planning. Despite their potential value, Local Indicators of Spatial Autocorrelation (LISA) measures have not been sufficiently exploited in monitoring the spatial and temporal variability in clustering and fragmentation of vegetation patterns in urban areas. LISA statistics are an important structural measure that indicates the presence of outliers, zones of similarity (hot spots) and of dissimilarity (cold spots) at proximate locations, hence they could be used to explicitly capture spatial patterns that are clustered, dispersed or random. In this study, we applied landscape metrics, LISA indices to analyse the temporal variability in clustering and fragmentation patterns of vegetation patches in Harare metropolitan city, Zimbabwe using Landsat series data for 1994, 2001 and 2017. Analysis of landscape metrics showed an increase in the fragmentation of vegetation patches between 1994–2017 as shown by the decrease in mean patch size, an increase in number of patches, edge density and shape complexity of vegetation patches. The study further demonstrates the utility of LISA indices in identifying key hot spot and cold spots. Comparatively, the highly vegetated northern parts of the city were characterised by significantly high positive spatial autocorrelation (p < 0.05) of vegetation patches. Conversely, more dispersed vegetation patches were found in the highly and densely urbanized western, eastern and southern parts of the city. This suggest that with increasing vegetation fragmentation, small and isolated vegetation patches do not spatially cluster but are dispersed geographically. The findings of the study underline the potential of LISA measures as a valuable spatially explicit method for the assessment of spatial clustering and fragmentation of urban vegetation patterns. 相似文献
5.
ANDREW S ROGOWSKI 《Transactions in GIS》1996,1(4):267-284
This study considers two issues of interest to the hydrologic and geographical information systems community. One deals with identifying the spatial distribution of infiltration and runoff contributing areas. The other addresses process modelling within a GIS framework. The study operates on the premise that partitioning of precipitation into runoff or infiltration depends on rainfall intensity and on soil properties. The problem is that neither local rainfall intensity, nor soil properties such as infiltration capacity and macroporosity are known well enough for all points of a catchment and need to be estimated. We infer local intensity from the interpolated distribution of cumulated rain depths over the catchment and record duration at the official met site. Measured values of sorptivity and hydraulic conductivity define infiltration. Negative head infiltration describes macroporosity. To scale-up measured point values to larger areas and to model infiltration and macropore continuity at a catchment scale we use geostatistical kriging and conditional simulation together with standard GIS techniques of overlay manipulation. Results delineate areas contributing to runoff and infiltration and relate them to macroporosity. By intersecting overlays of precipitation with those of infiltration we create alternate GIS masks targeting specific portions of the watershed as either runoff or infiltration contributing zones. Choice of cell size and time interval define the scales of averaging for the application. Kriged surfaces illustrate the distribution of catchment infiltration, while conditional simulation provides a mechanism to define model uncertainty. 相似文献
6.
针对城市及周边区域建造区和自然地表交织分布的特点,探讨了利用归一化植被指数(NDVI)和归一化建造指数(NDBI)构造趋势面的地表温度(LST)降尺度方法,以北京市市区及周边较平坦区域为例实现了LST自960 m向120 m的降尺度转换。分析了LST空间分布特征及NDVI、NDBI对地物的指示性特征;以北京市四至六环为界分析NDVI、NDBI趋势面对地表温度的拟合程度及各自的适用区域;在120 m、240 m、480 m和960 m 4个尺度上评价了NDVI、NDBI和NDVI+NDBI趋势面对LST的拟合程度和趋势面转换函数的尺度效应;对NDVI、NDBI和NDVI NDBI等3种方法的降尺度结果分覆盖类型、分区域对比评价。实验结果表明结合两种光谱指数的NDVI NDBI方法降尺度转换精度有所改善,改善程度取决于地表覆盖类型组合。 相似文献
7.
DEM数据是流域水文分析和模拟的基础,不同DEM分辨率尺度深刻影响着水文分析和水文过程模拟的结果。本文基于机载LiDAR获取的DEM数据,分析了不同分辨率LiDAR DEM在坡度提取、水文指数分析和流域特征参数提取中的差异及产生原因;基于SWAT分布式水文模型模拟研究了不同分辨率DEM数据的水文效应。研究结果表明：随着DEM分辨率的降低,坡度平均值减小,TWI平均值增大,SPI平均值减小,LSF均值先增大后减小,当分辨率为10 m时,LSF取得最大值;SWAT模型模拟结果表明,随分辨率的降低、坡度值的变小,地形湿度指数变大,蒸散发量增加,地表径流深减小,而土壤渗漏量与地下径流量则是先减小后增加,出现极值时DEM分辨率为10 m,与LSF出现极值时一致。 相似文献
8.
V. K. Pandey S. N. Panda N. S. Raghuwanshi S. Sudhakar 《Journal of the Indian Society of Remote Sensing》2006,34(2):143-152
Delineation of Banikdih Agricultural watershed in Eastern India was carried out and various watershed parameters were extracted
using Geographic Information System (GIS) and Remote Sensing. Digital Elevation Model (DEM) was developed with a contour interval
of 10 m in the scale of 1:25000 using ARC/INFO modules. Sub watershed, drainage, slope, aspect, flow direction, soil series,
soil texture, and soil class maps were independently generated and they were properly registered and integrated for analysis.
The watershed was digitally delineated using AVSWAT model that couples hydrological model and GIS with appropriate threshold
value of cell size. Subsequently, stream characteristics through the interface were generated. Indian Remote Sensing Satellite
IRS-1D LISS-III data pertaining to the period of October 29, 1998 and October 23, 2000 was used to develop land use/land cover
thematic map using ERDAS- 8.4 version image processing software. Eight major land use/land cover classes namely water body,
lowland paddy, upland paddy, fallow land, upland crop (non-paddy crops), settlement, open mixed forest, and wasteland were
segregated through digital image processing techniques using maximum likelihood algorithm. The information generated would
be of immense help in hydrological modeling of watershed for prediction of runoff and sediment yield, thereby providing necessary
inputs for developing suitable developmental management plans with sound scientific basis. 相似文献
9.
《地理信息系统科学与遥感》2013,50(4):583-599
High-resolution evapotranspiration (ET) maps can assist demand-based irrigation management. Development of high-resolution daily ET maps requires high-resolution land surface temperature (LST) images. Earth-observing satellite sensors such as the Landsat 5 Thematic Mapper (TM) and MODerate resolution Imaging Spectroradiometer (MODIS) provide thermal images that are coarser than simultaneously acquired visible and near-infrared images. In this study, we evaluated the TsHARP downscaling technique for its capability to downscale coarser LST images using finer resolution normalized difference vegetation index (NDVI) data. The TsHARP technique was implemented to downscale seven coarser scale (240, 360, 480, 600, 720, 840, and 960 m) synthetic images to a 120 m LST image. The TsHARP was also evaluated for downscaling a coarser 960 m LST image to 240 m to mimic MODIS datasets. Comparison between observed 120 m LST images and 120 m LST images downscaled from coarser 240, 360, 480, 600, 720, 840, and 960 m images yielded root mean square errors of 1.0, 1.3, 1.5, 1.6, 1.7, 1.8, and 1.9°C, respectively. This indicates that the TsHARP method can be used for downscaling coarser (960 m) MODIS-based LST images using finer Landsat (120 m) or MODIS (240 m)-derived NDVI images. However, the TsSHARP method should be evaluated further with real datasets before using it for an operational ET remote sensing program for irrigation scheduling purposes. 相似文献
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11.
基于GIS的乌江流域地表径流模拟研究 总被引：2，自引：0，他引：2
基于GIS平台，建立了数字乌江流域。在此基础上，选择5个典型子流域，利用流域1956-2000年的降雨和水文资料及流域2000年土地利用数据，分别计算5个子流域的年均降雨量、年均地表径流量和土地利用百分比；用多元回归分析工具建立流域年均地表径流量与年均降雨量和土地利用百分比之间的关系式，得到不同土地利用方式下的降雨径流模型；通过实测资料对模型进行验证的结果表明，模型模拟精度较高，相对误差在7％以内。 相似文献
12.
J. P. Singh Darshdeep Singh P. K. Litoria 《Journal of the Indian Society of Remote Sensing》2009,37(1):21-35
A case study has been conducted to identify suitable sites for water harvesting structures in Soankhad watershed, Punjab using
information technologies such as Remote Sensing and Geographical Information System (RS-GIS). The IRS-1C, P6 satellite imagery
of the Soankhad watershed was used. The various Thematic maps such as land use map, hydrological soil group map, slope map
and DEM map were prepared for selecting suitable site for construction of water harvesting structures. The suitable sites
were not found for nala bunding and farm ponds due to steep slope, less soil thickness and high runoff velocity. Fourteen
check dams and six percolation tanks were proposed for the construction as per Integrated Mission for Sustainable Development
(IMSD) guidelines. The water balance study of the Soankhad watershed was also computed with monthly mean temperature and rainfall
data using TM model. The average runoff for the wet season (July–September) 1996 was computed to be about 1543.82 mm and the
total runoff volume from the Soankhad watershed was estimated to be about 143.52 Mm3. 相似文献
13.
M P Tripathi R K Panda S Pradhan S Sudhakar 《Journal of the Indian Society of Remote Sensing》2002,30(1-2):39-52
This study was conducted for the Nagwan watershed of the Damodar Valley Corporation (DVC), Hazaribagh, Bihar, India. Geographic Information System (GIS) was used to extract the hydrological parameters of the watershed from the remote sensing and field data. The Digital Elevation Model (DEM) was prepared using contour map (Survey of India, 1:50000 scale) of the watershed. The EASI/PACE GIS software was used to extract the topographic features and to delineate watershed and overland flow-paths from the DEM. Land use classification were generated from data of Indian Remote Sensing Satellite (IRS-1B—LISS—II) to compute runoff Curve Number (CN). Data extracted from contour map, soil map and satellite imagery, viz. drainage basin area, basin shape, average slope of the watershed, main stream channel slope, land use, hydrological soil groups and CN were used for developing an empirical model for surface runoff prediction. It was found that the model can predict runoff reasonably well and is well suited for the Nagwan watershed. Design of conservation structures can be done and their effects on direct runoff can be evaluated using the model. In broader sense it could be concluded that model can be applied for estimating runoff and evaluating its effect on structures of the Nagwan watershed. 相似文献
14.
研究城市设施的热点分布对把握当前城市形态具有重要意义。传统的设施热点识别方法容易忽略设施的特征尺度且多以区域识别为主,缺少精准化提取设施热点的方法体系。针对上述问题,本文提出了一种顾及属性特征的设施热点识别方法,并以北京市住宅设施为例进行了试验分析。首先将设施的属性值作为权重,进行加权核密度估计生成密度值表面,利用极值点探测模型提取极值点;然后采用Getis-Ord Gi*统计进行空间自相关分析,生成具有显著统计学意义的热点区域,筛选极值点得到热点。结果表明,该方法能够准确有效地识别设施热点并进行合理的等级划分,为城市设施空间布局研究提供多样化视角。 相似文献
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16.
Mahtab Safari Shad Mahmoud Habibnejad Roshan Alireza Ildoromi 《Journal of the Indian Society of Remote Sensing》2014,42(1):107-117
Because of the difficulty of monitoring and measuring snow cover in mountainous watersheds, satellite images are used as an alternative to mapping snow cover to replace the ground operations in the watershed. Snow cover is one of the most important data in simulation snowmelt runoff. The daily snow cover maps are received from Moderate Resolution Imaging Spectroradiometer (MODIS), and are used in deriving the snow depletion curve, which is one of the input parameters of the snowmelt runoff model (SRM). Simulating Snowmelt runoff is presented using SRM model as one of the major applications of satellite images processing and extracting snow cover in the Ghara - Chay watershed. The first results of modeling process show that MODIS snow covered area product can be used for simulation and forecast of snowmelt runoff in Ghara - Chay watershed. The studies found that the SCA results were more reliable in the study area. 相似文献
17.
Christopher A. Day 《国际地球制图》2013,28(7):543-554
Land cover changes within watersheds have the potential to produce dramatic changes in surface hydrology, namely runoff, in the event of storms. The Mid-Cibolo Creek watershed in south-central Texas has experienced extensive land-cover change in the past two decades due to mass residential development and land clearing in the wake of urban growth along the I-35 corridor. This study determined land-cover changes within the basin using supervised classification to classify land cover from LANDSAT images for the years 1986 and 1999. Changes in runoff volume were then calculated using the Soil Conservation Service (SCS) runoff equation for a series of rainfall scenarios. The results showed that an overall increase in impervious cover and decrease in natural vegetative cover has occurred leading to larger runoff volumes for all storm scenarios. The findings are important for watershed scale urban expansion and land clearing practices as current methods suggest that flood risk is increased. 相似文献
18.
P. K. Shrivastava M. P. Tripathi S. N. Das 《Journal of the Indian Society of Remote Sensing》2004,32(2):145-157
A distributed parameter model Soil and Water Assessment Tool (SWAT) has been tested on daily and monthly basis for estimating surface runoff and sediment yield from a small watershed “Chhokeranala” in eastern India using satellite data and Geographical Information System (GIS). Several maps like watershed and sub-watershed boundaries, drainage network, landuse/cover and soil texture have been generated. The SWAT model has been verified for the initial phase of monsoon season in the year 2002 using daily rainfall and air temperature. Performance of the model has been also evaluated to simulate the surface runoff and sediment yield on sub-watershed basis for two months (July-August 2002). The results show a good agreement between observed and simulated runoff and sediment yield during the study period. Capability of the model for generating rainfall has been evaluated for 10 years (1992 - 2001) period. The model simulated daily rainfall shows close agreement with the observed rainfall. The present results show that the SWAT model can be used for satisfactory simulation of daily and monthly rainfall, runoff and sediment yield. 相似文献
19.
This study reports results from evaluation of the quality of digital elevation model (DEM) from four sources viz. topographic map (1:50,000), Shuttle Radar Topographic Mission (SRTM) (90 m), optical stereo pair from ASTER (15 m) and CARTOSAT (2.5 m) and their use in derivation of hydrological response units (HRUs) in Sitla Rao watershed (North India). The HRUs were derived using water storage capacity and slope to produce surface runoff zones. The DEMs were evaluated on elevation accuracy and representation of morphometric features. The DEM derived from optical stereo pairs (ASTER and CARTOSAT) provided higher vertical accuracies than the SRTM and topographic map-based DEM. The SRTM with a coarse resolution of 90 m provided vertical accuracy but better morphometry compared to topographic map. The HRU maps derived from the fine resolution DEM (ASTER and CARTOSAT) were more detailed but did not provide much advantage for hydrological studies at the scale of Sitla Rao watershed (5800 ha). 相似文献
20.
Nowadays watershed management plays a vital role in water resources engineering. Watershed based on water resources management
is necessary to plan and conserve the available resources. Remote Sensing (RS) and Geographic Information System (GIS) techniques
can be effectively used to manage spatial and non spatial database that represent the hydrologic characteristics of the watershed
use as realistically as possible. The present study area is Malattar subwatershed (4C2B2) lies in the region Gudiyattam Block,
Vellore District, Tamil Nadu. The daily rainfall data of Gudiyattam rain gauge station (1971–2007) was collected and used
to predict the daily runoff from the watershed using Soil Conservation Service — Curve Number (SCS — CN) method (USDA, 1972)
and GIS. Monthly and annual runoff have been calculated from the monthly rainfall data for the years of 1971 to 2007 in the
watershed area. The average minimum and maximum rainfall for the years of 1971 to 2007 is 35.30 mm and 111.61 mm respectively
and average runoff for the year of 1971 to 2007 is 31.87 mm3 and 47.04 mm3 respectively. The developed rainfall-runoff model is used to understand the watershed and its runoff flow characteristics. 相似文献