An informative blogpost from Sushant Potdar - an intern with BIOME Environmental Trust . Reproduced from
Topographic sheets provide valuable data about the area that is being studied. It is one sheet which provides enormous data from natural features to man made structures of that particular area. The topographic sheets find their uses in the field of population, town planning, soil, water, forest, pollution and so on. The body that generates and prints these topographic sheets in India is a government organization known as Survey of India (SoI). It is a very old organization started by the British to survey and prepare maps of India for their use. Its headquarters is situated at Dehradun in Uttarakhand state. But there are many other regional offices all across India to obtain these topographic sheets of a particular area of interest. There are four scales of topographic sheets that can be obtained from SoI. This depends on the study area and the kind of study one wants to carry out. The scales are 1:1,000,000 (1:1M) ; 1:250,000 (1:250K) ; 1:50,000 (1:50K) and 1:25,000 (1:25K). The topographic sheets have proper indexing done by the SoI itself. Thus, it is easy to obtain a desired topographic sheet from the SoI reference map. The link to that reference map is attached below:
My study is to map the open wells near Sarjapura road in Bengaluru and in Devarayasamudra in Kolar Dist. Since my study area is comparatively small, I decided to use 1:25,000 scale map. The procedure that I followed in obtaining these topographic sheets are as follows:
1. I first went to the Survey of India website and checked if the topographic sheets of my study area is available or not. This can be done by looking under the “Availability of OSM” section (Here, OSM means Open Street Maps which is a bit larger than topographic sheets. The indexing is different for OSM but can be converted to topographic sheet indexing). Later select the available state under that option and check for availability of OSM.
2. Later, I found out the index of my topographic sheet that I needed. It is important to know this because when you visit the SoI office, the index should be mentioned to the person in charge as it will be easier to find it among many topographic sheets. My study sites lie in topographic sheet numbers 57 H/9 and 57 K/8 respectively. These are index numbers for 1:50,000 scale maps. For 1:25,000 maps, the indexing is further mentioned as NW, NE, SW, SE after the initial 1:50,000 scale index.
For example, 1:1000,000 scale has index number 57 ; 1:250,000 scale has index number 57 A-P ; 1:50,000 scale has index number 57 A-P/1-16 and 1:25,000 scale map has index number 57 A-P/1-16 NW/NE/SW/SE.
3. I found out regional offices of SoI in Bangalore. The office is situated in Koramangala 2nd block on Sarjapura road. The detailed address is given below:
Survey of India Staff Quarters, Koramangala 2B block, Sarjapura road, Bengaluru- 560034
4. I visited the office and went into the map selling room in the campus. It is located just near the entrance gate after entering from Sarjapura road. The necessary topographic sheets were asked but 1:25,000 scale maps were unavailable. Thus, 1:50,000 scale maps were purchased.
5. If the maps are available, then they can be purchased immediately. This costs Rs. 95/- per topographic sheet of 1:50,000 scale. If only the office copy of the topographic sheet is available, then the copy is scanned, printed and given to you. This takes about 2 days and costs Rs. 305/- per topographic sheet. But this cannot be purchased immediately as scanning and printing requires time. A form is supposed to be filled to obtain these sheets mentioning the purpose of use.
6. Once the printing is finished, they call you and inform you to collect the topographic sheets.
7. Once the topographic sheets are obtained, it can be used for the required purpose. In my case I will use it to identify the open wells and study them by locating it on the ground.
Thus, the topographic sheets are of high importance in various fields of study and I have just shared my experience in obtaining these sheets for my study.