GIS data can be extracted from paper maps, satellite images and aerial photographs. Conversion of raster image to vector layer, known as Vectorization is one of the basic services comes under GIS map making activities.
In general, the vectorization process starts with scanning of paper copy maps, drawings, cadastral sheets, utility plans etc. to get it converted in to digital format. Depending on the necessity stitching and mosaicking of adjacent images have been done followed by conversion of images in to vector layers represented as point, line and polygon objects. For conversion of images to vector layers we use advanced GIS software platform including ArcGIS, MapInfo, AutoCAD Map etc. to deliver output in universally acceptable GIS file format as per client’s requirements.
Cadastral Sheet Digitization
Cadastral sheet digitization is one of the most common type of map conversion activity comes under GIS services. The overall process involves series of activities starting from scanning of existing mouza sheets, stitching, mosaicking of adjacent sheets, vectorization of raster image in to multiple vector layers like village boundary, sheet boundary, plot boundary, road, nallas, other existing objects and incorporation of all available attributes like village details, sheet no., plot no. etc.
Availability of old paper copy maps as urban/ town plan and utility are very common in developing country like India. Thus, for all urban bodies, conversion of those existing maps in to digital and editable format become essential for their day-to-day infrastructure maintenance, utility services and future plans. Digital conversion of all existing maps/ drawings etc. added with partial field verification can produce useful digital map including vector layers like urban boundary, ward boundary, land use, transportation network, drainage & sewages, water supply network, important land marks, other various infrastructures etc.
Utilizing digitized vectors in association with information from other sources like socio-economical survey etc. thematic mapping can be done for various departments of urban body for their future planning. For example, identification of slum area and necessary infrastructure can be thematically represented utilizing digital map along with socio-economical data of that area.
Digitization from Satellite Imagery
Identification of features and extract vector layers for wide range of features categories like land base, forest coverage, water body, transportation, habitation, building footprint etc. utilizing different types of Satellite Imageries through the process of vectorization.
Survey and Mapping
Survey is one of the appropriate and reliable data collection methods of GIS mapping especially for industries like utility, land management, urban development and planning, disaster management etc. There are basically two types of data needs to be collected in GIS; one is spatial data and another is attribute information.
Now days, different types of advanced survey methods are used mainly to collect spatial information of objects as well as related attributes. Some of the well adopted methods are GPS/ DGPS survey, Total Station survey etc. Some of the other basic survey methods are also in significant use like cadastral survey, leveling, hydrographic survey, door-to-door survey etc.
Utilizing the collected spatial and non-spatial data through the different methods of survey, GIS can be developed for thematic visualization and data analysis through the standard mapping techniques as per different industry and requirements.