[Proj] ITRF96/UTM 36N conversion
fernandohoze
muranyum at yahoo.com
Sat Aug 8 14:12:09 EST 2009
José Alberto Gonçalves wrote:
>
> In order to convert UTM-36N to long-lat with output in decimal degrees you
> can use the following PROJ command line:
> proj -I -f "%.9f" +ellps=WGS84 +proj=utm +zone=36
Thank you all for your replies. I tried the command José wrote (with -r flag
- thanks Gerald) and it worked well. The command also works without
reformatting the input.
About calculating distance between two points... José, I examined the
program you recommended but and I have some results but I need to make sure
that they are correct. Here is what I did:
First of all, here are the input points:
4415488.923061 481668.789218
4415490.272973 481668.977703
I found latitude and longtitude using the following command:
proj -r -I -f "%.9f" +ellps=WGS84 +proj=utm +zone=36
Results:
32.785593500 39.889265833
32.785595667 39.889278000
So, when I wrote these into Google Maps (in reverse order,) it correctly
showed the points:
39.889265833 32.785593500
39.889278000 32.785595667
Then, I executed the following geod command:
geod +ellps=WGS84
As input I wrote the above numbers. As output I received the latitude and
longtitude in degree/minute/second format:
39d53'21.357"N 32d47'8.137"E 180d
39d53'21.401"N 32d47'8.144"E 180d
Then, I executed this command for distance calculation:
geod +ellps=WGS84 -I +units=km
And entered the above coordinates as input:
39d53'21.357"N 32d47'8.137"E 39d53'21.401"N 32d47'8.144"E
The result was:
6d59'12.829" -173d0'47.167" 0.001
0.001 at the end of the result tells that the distance is around 0.001 km
that is 1 meters. So, I tried the command with +units=m and the result was
6d59'12.829" -173d0'47.167" 1.368
That is 1.368 meters, which seems to be correct. I did the same calculation
using http://www.movable-type.co.uk/scripts/latlong.html this web page and
the result was 0.001369 km. So, I guess I used the correct commands. The
inputs I used for the web page were like that:
Lat 1: 39 53 21.357N
Long 1: 32 47 8.137E
Lat 2: 39 53 21.401N
Long 2: 32 47 8.144E
There is one problem here that I don't get. When I use cm or dm for +units
option, I still get 1.368 insted of 136.8 for cm and 13.86 for dm. Actually,
if I don't use any +units option, I still get 1.368 as the result. Is there
something wrong with the command I use or am I missing something?
I also tried everything above with the following inputs:
4415475.022910 481656.729116 918.850000
4415473.636002 481656.540539 918.850000
And in the end I got 1.195 as the results, which is reasonable. The web site
gave 0.001194 km.
I tried to write everything I did step by step. Could you please tell me if
above calculations are correct or not. Also I would appreciate if you tell
me a command that would do all the computation above.
--
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