An informative blogpost from Sushant Potdar - an intern with BIOME Environmental Trust . Reproduced from
https://sushantpotdar55.
https://sushantpotdar55.
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.