Showing posts from August, 2020

Cartosat DEM Processing using QGIS- Reproject, Clip and Stream Generation

This article in continuation of earlier article on downloading and processing of Cartosat DEM. this article, processing of DEM is explained such as re-project, clip and fill the Gaps and remove error present in DEM. These correction can be performed using GIS functions. Reprojection is needed for correcting geometric errors present in DEM as well as convert projection system one to another. GIS tools can be used for Clipping of DEM is very important especially for watershed delineation, for this clipping boundary based on study will be used. Error present in DEM is defined as sudden extreme high and low values occur in comparison to surrounding values.  Step 1 – Re-project the mosaic DEM using QGISHere we will change the CRS from Geographic to UTM. For this click on Rasterthen Projections followed by Warp (Reproject).
Warp (Reproject) window will popup. Here define Input layer and Target CRS (Co-ordinate Refe…

Download Cartosat DEM Through BHUVAN Portal

Cartosat DEM Download and Mosaicing Process using QGISThis article is prepared to discuss steps to download Cartosat DEM through bhuvan portal. As this DEM downloaded in tiles so one may need more than one DEM tile for study area. Therefore it is necessary to mosaic these tiles to make a single tile of DEM. In this steps of both processes- download and mosaic are shared to create DEM, which can be further used further for different remote sensing and GIS based applications. Such as Agricultural StudiesWetland studiesWatershed StudiesRunoff and Sediment Discharge StudiesUrban Sprawl MappingTransport Studiesetc.Step 1 - Download freely available DEM data using NRSC-Bhuvan websiteOpen weblink: this page go to top menu option – Open Data ArchiveA new window will open after clicking on Open data Archive.You need to make user id on this page, so click to Login (on the extreme top right corner) After login Select the area of which you …


Remote sensing is used for change detection and analysis of different earth surface features; it includes both man-made and natural features. These features can be combined in a one thematic map, which can be named as land use/land cover map. Features which are selected to include in land use/land cover map largely depends upon the objective of work/project as well as satellite image selected for project/study. As spatial and spectral propertiesof satellite image plays significant role in acquiring satellite image based on project/study objective. In this change detection analysis, multi date satellite images need to use and satellite image should have same season/acquiring date and month. Based on satellite image selection using spatial and spectral properties, level of classification is decided for land use/land cove map.Level of classification can be understood with this example in below figure- Figure 1 Classification Level for Land use/Land Cover Map These satellite image will be p…

GIS for Spatial Analysis-Public Transport Access Analysis

Spatial data can be manages and analyzed using GIS. In current, GIS application is increased in transportation studies especially in planning and management. Public transport system is an important part to manage and plan for urban development. Public transport symbolizes as an efficient mode to travel by the people for different purposes in the specific region with the less impact on the environment. Therefore urban planners and decision makers need to identify useful approach to deal with resistance of people to travel by public transport. It is become important to evaluate and identify the areas which are poorly connected with public transport system but at the same time those areas need to provide public transportation due to availability of high rate of potential users. Public transport system is accessed through its stop/station, so it is important to know and estimate coverage area of stop/station. The coverage area is significant for public transport that the increase in the w…

Remote Sensing Data integrated with Landscape Metrics for Urban Sprawl Analysis

Remote Sensing data can be applicable in many fields as direct use to assess change for monitoring and in many models as input data for further analysis. Selection of remote sensing images to create spatial database is mainly depend on user requirement and these satellite image can be selected for spatial database generation based satellite imagecharacteristics, which can be explained by below parameters of satellite image-Spatial ResolutionSpectral ResolutionTemporal Resolution and Radiometric ResolutionBased on above property satellite images can be selected by user then basic image processing steps need to follow to create accurate spatial dataImage Geometric correctionsImage Radiometric correctionsImage EnhancementImage ClassificationAccuracy assessment to accept spatial data for further analysisThese spatial data created using satellite images can be used in simulation andmathematical model/method. In this article these spatial data are analyzed using Landscape metrics to assess …

Remote Sensing and GIS for Spatial Analysis- A Scenario Based Analysis Approach

Remote Sensing process is very significant to keep watch on earth surface features including both man-made and natural. Satellite image acquired and processed in image processing software to create spatial data. These spatial data can be further used as input data in different mathematical models to analyze the change and to find trends in future for policy planning and implementation.GIS software also used to create input data and those spatial data can further integrated in models to analyze current as well as future scenario. GIS has many functions and tools which can be employ to find the impact in that area as well as to analysis impact of neighborhood or vice versa.  In this scenario analysis, the urban area has been re-simulated for 2015 and 2025 by including commercial and industrial areas proposed in the 2025 land use plan. The aim of this analysis is to ascertain the impacts of commercial and industrial areas on urban change. The variable proximity to commercial and industri…