Something on GIS
So the very first post on the subject I am working for quite a long time now. Traversed from one company to another, going through several projects and various technologies, didn't write anything on the work I do in the closed enclosures of my office.
To start with, as of now I am working on a piece of work, which is for renovating an existing portal for the client, which would have GIS map application as a part of its GUI.
In my early days with GIS, I worked only on Desktop GIS applications for creating GIS data. So If I talk about the source of data which we used as a base to create GIS data -
- Ground survey data : This data is captured by the surveyors (whom I have always seen as poor people, who do all the hard work on the ground). They capture the data by having some GCPs (Ground Common Points) and surveying other details around these GCPs. GCPs are actually points on ground for which they know the actual coordinates.They use devices to gather that data which was "Total Station", It's an electronic Theodolite to measure slopes and distances. Now a days GPS devices are used for this purpose. I'll cover more information and methods in some other post. The survey is only used when there is no data at all or you want to capture new data.
- Old printed Maps : These were also very wonderful pieces of information. In one of my project for MRSAC (Maharashtra Remote Sensing Application Centre, Nagpur) we used old printed map as our source data. Old maps would amaze you for revenue maps, by which states earns revenues and keep records of rural land parcels were printed on cloths. We used to scan these maps to digitalize these, then how to scan cloth maps ? But anyhow we managed to scan those as well.
- Satellite Imageries : We know satellites take pictures of earth from the space for various purposes varying on the level of details they are capturing.So there are some distinguished analysts who interpret desired information from Images to trace papers and then scan these captures as GIS source data. The information could vary from level of ground water to type of vegetation to crops on the land and what not.
