Journal on Geoinformatics, Nepal https://nepjol.info/index.php/NJG <p>Annual publication of the Survey Department, Government of Nepal. Full text articles available.</p> Survey Department Government of Nepal en-US Journal on Geoinformatics, Nepal 2717-5022 © Copyright reserved by Survey Department, Government of Nepal Editorial Vol.23 https://nepjol.info/index.php/NJG/article/view/66042 <p>No abstract available.</p> Susheel Dangol Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-30 2024-05-30 i ix Assessing the Impact of Urban Expansion on Forest Cover using LULC Maps, NDVI, and NDBI: A Case Study of Kathmandu District https://nepjol.info/index.php/NJG/article/view/66045 <p>Rapid urbanization poses significant challenges to the delicate balance between urban development and environmental conservation. This study investigates the impact of urban expansion on forest cover in the Kathmandu District, employing a comprehensive approach that integrates Land Use/Land Cover (LULC) maps, Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-Up Index (NDBI). The aim of the study area is to provide insights into the dynamic interplay between urban growth and its consequences on the region's ecological landscape. LULC maps derived from remote sensing data offer a spatially explicit representation of land-use changes over time, enabling the identification of areas where urbanization has encroached upon forest area. The NDVI, a vegetation health indicator, serves as a quantitative measure of changes in the density and health of vegetation cover, aiding in the assessment of ecological impacts. Complementing this, the NDBI highlights intensity of built-up areas, allowing for a nuanced understanding of the urbanization process. This study employs NDBI and NDVI to dynamically assess urban growth and land use cover change, enhancing analytical accuracy. Findings reveal a substantial 89.9 km² increase in built- up areas between 2013 and 2016, coupled with a minor 18.4 km² increase between 2016 and 2021, reflecting continuous urban expansion driven by population growth and development initiatives. Concurrently, forest area marginally increased by 2.3 km² in 2016, suggesting reforestation and conservation efforts, yet a subsequent 23.5 km² decline by 2021, due to deforestation, urban encroachment, and natural disasters such as wildfires. Notably, vacant land decreased by 92.3 km² in 2016, absorbed by built- up areas and forest expansion, underscoring the urgent need for spatial planning to accommodate the growing population and its evolving needs.</p> Arun Kumar Bhomi Rabina Poudyal Suraj Kumar Tolange Susmita Chaudhary Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 1 7 10.3126/njg.v23i1.66045 Cadastre in Nepal: Need for 3D and Way Towards 4D https://nepjol.info/index.php/NJG/article/view/66046 <p>Increase in population and its migration towards urban areas are leading to unmanaged urbanization generating pressure on the land. To meet the demand of migrating people, high rise buildings are being developed. Since land is a limited resource, this is a better solution. Rights on vertical strata in the same parcel need to be recorded technically and legally in cadastral data as well as land registers. In Nepali context, despite some limited legal provisions for recording 3D cadastral data, there is still a gap in recording spatial information technically. On the other hand, due to the lack of clear spatial information recording and limited provisions for recording in land registers, land disputes are also arising. However, an increase in land dispute cases is not the only issue; there are a huge number of reasons related to legal and technical provisions in land administration. Therefore, in order to minimize land dispute cases, 4D cadastre can provide a better solution. The paper discusses the legal provisions of 3D cadastre and its need in the context of Nepal, along with the need for 4D cadastre to support in reducing land dispute cases.</p> Pravesh Yagol Susheel Dangol Prakash Joshi Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 9 17 10.3126/njg.v23i1.66046 Climate Change and Flood Vulnerability Analysis in the Narayani River of Nepal https://nepjol.info/index.php/NJG/article/view/66047 <p>Flood disasters annually devastate livelihoods, particularly during the monsoon season, with no apparent reduction in impacts in low-lying regions of developing countries like Nepal. Given the increasing effects of climate change globally, this study aims to assess climate change effects and biophysical vulnerability of riverine communities to floods in the Narayani River of Nepal, elucidating the interrelationship between these phenomena. This paper presents an analysis of trends and extreme events of climatological variables, such as temperature, precipitation, and daily river discharge and hazard mapping and risk assessments in the river stretch of two Village Development Committees (VDCs) in the country’s inner Terai region of Nawalparasi district for different return-period floods, with the aid of the HEC-RAS (Hydrologic Engineering Centre’s River Analysis System) and HEC-GeoRAS. A long-term climatological data was collected from the Department of Hydrology and Meteorology, Kathmandu, and the analysis was performed using statistical softwares, SigmaStat, and SigmaPlot. In addition, flood conditions representing 2, and 100-year periods were determined using Gumbel’s distribution. The study revealed a narrowing temperature range, with increasing minimum temperatures and decreasing maximum temperatures, precipitation, and river discharge. However, there was a notable increase in extreme events. The hazard mapping indicated the people’s vulnerability to inundation and soil erosion along the low-lying riverbanks. The findings underscore the necessity for reliable technological and socio-economic vulnerability mapping to provide early warnings to at-risk populations. This paper argues that unplanned and mismanaged settlements in riverine areas may lead to population displacements, creating environmental refugees.</p> Kiran Maharjan Susheel Dangol Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 19 33 10.3126/njg.v23i1.66047 Comparison of the Direct Supervised Classification and Segment Mean Shift Classification: A Case Study of Hetauda Sub-Metropolitan City of Nepal https://nepjol.info/index.php/NJG/article/view/66048 <p>Comparison between Land Use Land Cover (LULC) classification and methods is a common practice to assess their suitability and reliability in specific areas. In the case of Hetauda Sub-Metropolitan City in Nepal, Sentinel-2B satellite imagery was utilized to evaluate the accuracy of LULC classification through both direct supervised classification and segment mean shift classification. Direct supervised classification was conducted in ERDAS Imagine, while segment mean shift classification was performed in ArcGIS to identify six LULC classes: forest, agriculture, built-up area, bare area, grassland, and waterbody. Pre-processing steps such as layer stacking, mosaicking, data extraction, atmospheric and radiometric correction were employed to enhance the imagery. Training samples were chosen via visual interpretation based on local knowledge to train the Maximum Likelihood Classifier (MLC). The results revealed that the segment mean shift method achieved the highest overall accuracy at 90%, whereas direct supervised classification yielded 85%. Furthermore, kappa statistics indicated a strong level of agreement, with segment mean shift scoring the highest at 0.88 and direct supervised classification at 0.81. Individual class accuracies varied, with forest classification being the most reliable at 98% and waterbody classification at 71%. Overall, the segment mean shift method was deemed more accurate and suitable than the pixel-based direct supervised classification for LULC classification in Hetauda Sub-Metropolitan City, Nepal.</p> Menaka Hamal Prof. Shahnawaz Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 35 47 10.3126/njg.v23i1.66048 Integration of GNSS, Total Station, and Grid Controls: An Analysis of Combined Effect of Elevation of Topography and Map Projection Distortion to Solve the Distance Discrepancy https://nepjol.info/index.php/NJG/article/view/66049 <p>Heterogeneous measurements from various surveying methods need to be integrated to accomplish any survey project. The use of Global Navigation Satellite System (GNSS) and Total Station (TS) to establish a control framework along with utilizing existing national grid controls, for any survey project has been the standard practice. However, the successful integration of GNSS, TS, and existing grid controls could be challenging at times. Both survey professionals, and surveying stakeholders would benefit from the successful augmentation of heterogeneous measurements from GNSS, TS, and existing grid controls in order to provide a control framework for their survey project. In the past, the distance discrepancy/mismatch of GNSS-derived distance which is obtained from indirect measurements from GNSS survey and TS distance which is ground-based direct measurements, has created confusion. Herein, we have analyzed in detail, the combined effect of elevation of topography and map projection's distortion on the distance; demonstrate the magnitude of combined effect by numerical examples; tested this formulation with real-world GNSS and TS measurements. This way we proposed a solution to solve distance discrepancy/mismatch between various survey methods. The magnitude of the combined effect would be substantial with higher elevations and longer distances and could cross the threshold of specified/required accuracy. The effect would be more pronounced in mountainous regions suggesting combined effect should be properly taken into account. Taking combined effect into consideration brings the compatibility and comparability of GNSS, TS, and existing grid controls together. Thus, allowing both survey professionals and surveying stakeholders to utilize the mix of GNSS, TS, and existing grid controls to achieve required precision and accuracy in an economical, timely, and easy manner.</p> Shanker KC Suresh Shrestha Sandesh Upadhyaya Stallin Bhandari Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 49 61 10.3126/njg.v23i1.66049 Landslide Susceptibility Analysis and Hazard Zonation in Nuwakot District, Nepal https://nepjol.info/index.php/NJG/article/view/66097 <p>Landslide mostly occurred in highly rugged topography, erosional steeply sloping land form and fragile geological structural in mountainous region. Landslide susceptibility describe the likelihood relation of occurring landslide in an area controlled with their local terrain condition. Landslide susceptibility analysis (LSA) work is used to determine the spatial distribution of landslides prone area and applicable to predict the future landslides occurrences, which is vital for averting and mitigating regional landslide disasters. LSA. In this study, LSA is carried with the bivariate analysis incorporating twelve causative factors of landslide. The frequency ratio (FR) technique were used for computing the relative frequency (RF) as priority rank and entropy index (E) as weight of causative factor. Result of LSA shows that the probability of occurring landslides is 80 percent, with 27 percent of that risk being high risk, 38 percent being medium risk, and 15 percent being low risk. The prediction accuracy of the model is 87.89 percent, showing reliable and satisfactorily validation rates with good accuracy. So, the present study demonstrates that the quantitative assessment methods explored may have a promising potential for landslide assessment and prediction in the high hill and Himalaya regions.</p> Bikash Kumar Karna Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 63 70 10.3126/njg.v23i1.66097 Mapping and Analysing Suicide Locations of Lalitpur, Nepal https://nepjol.info/index.php/NJG/article/view/66263 <p>This research utilizes geospatial and statistical analysis to examine spatial patterns in suicide occurrences within the Lalitpur district of Nepal. The dataset comprises suicide locations collected from the Lalitpur Police Range (LPR) over a period of six fiscal years spanning from 2074/75 to 2078/79 (2017 AD to 2023 AD). Textual data undergo preprocessing and geocoding processes to derive locations for spatial analysis. The methodology employs Local Moran's I to identify spatial patterns and Getis Ord Gi* to identify hotspots and coldspots of suicide incidents. Due to location approximations, spatial analyses are conducted at aggregated levels, including administrative units (wards level) and 1km x 1km grids. The study reports the identified hotspots and coldspots based on these analyses.</p> Dinesh Khatri Dashrath Ghimire Poshan Niraula Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 71 79 10.3126/njg.v23i1.66263 Modified One-Point-and-Area Algorithm for Sub-division of Irregular Parcels https://nepjol.info/index.php/NJG/article/view/66266 <p>Parcel sub-division is a crucial part of the Land Administration, and its techniques depend on the user requirements and other constraints. Splitting of a parcel based on a given area is one of such constraints whose subdivision has been popularly carried out using the trial-and-error method which is less accurate and time-consuming. For more accurate and direct subdivision, Habib developed algorithms based on popular eight cases. Among them, when the area to be split is known, a point or line is selected as a reference. In case if it has to be a point, then a one-point-and-area method is used for subdivision while a move-line-and-area method is used if line segment is used as reference. It was found that Habib Algorithm worked well for convex shapes, however it could not account for the concavity of irregular-shaped parcels. It was found that the approach for the calculation of the area considered only the cases of convex shapes. Therefore, the researchers observed the issues of clinging and retracting were identified. Thus, this study proposes an effective algorithm for the division of an irregular parcel using an improved version of One-Point-and-Area method used in Habib Algorithm. An additional stage of generating a convex hull was introduced to guide the iteration process, the formula to calculate area was adjusted to compute only the interior area and finally, the determination of the partition polygon was also done through an iterative improvement process rather than the existing one-step process. Experiments showed that the proposed algorithm accurately divided both irregular-shaped parcels and convex parcels. In the case of convex parcels, the result was found to be the same as Habib’s method. Due to the addition of an extra stage of generating a convex hull and extra iterations in the final stage, the proposed algorithm consumed more time. However, it was found negligible in regard to the volume of parcels involved in splitting at a time. Overall, the proposed algorithm accurately solved the issues of clinging and retracting irregular polygons and without changing the results in convex polygons. So, it was concluded to be a suitable replacement of Habib Algorithm, and its implementation will provide more accurate results in parcel sub-division problems.</p> Amrit Karmacharya Janak Parajuli Shrisha Makaju Shrestha Copyright (c) 2024 Survey Department, Government of Nepal 2024-05-29 2024-05-29 81 94 10.3126/njg.v23i1.66266