[Proj] cs2cs syntax help

[Szilard Albert]

Thank you Hermann,

just did a quick comparison of the results after using invproj, seem to
have the same result.
regards,
Szilard



On 24 October 2013 16:52, Hermann Peifer <peifer at gmx.eu> wrote:

> On 2013-10-24 6:46, Szilard Albert wrote:
>
>> The task is to convert UTM Zone 53 XY coordinates into Lat/Lon
>> coordinates, keeping datum.
>>
>
> For this task, you don't really need cs2cs. proj -I or invproj can be
> used. See below.
>
>
>> I am using:
>>
>> *cs2cs -W2 +proj=utm +zone=53 +south  +datum=WGS84 +to  +proj=latlong
>> +datum=WGS84
>> 669734.6 7607027.2
>> 136d38'24.07"E  21d37'54.60"S 0.000*
>>
>> getting a result that seems fine.
>>
>> However, the following issues arise:
>>
>> 1. My input data is on the GDA94 datum. When I try  +datum=GDA94 (or
>> GDA), I get
>> /<cs2cs>:
>> projection initialization failure
>> cause: unknown elliptical parameter name./
>>
>
> proj -ld (or cs2cs -ld) gives the list of known datums. GDA or GDA94 are
> not mentioned there. However, you do not have to worry, as you anyway want
> to keep the datum.
>
>
>> Am I safe using WGS84, since the difference between these 2 datums is
>> less than 1 m? (http://www.geoproject.com.au/**gda.faq.html<http://www.geoproject.com.au/gda.faq.html>
>> ).
>>
>> 2. I have heaps of other parameters of my input data - as below - should
>> any of these be incorporated in my command,
>> or datum and zone are enough?
>>
>> Datum GDA94
>> Spheroid GRS80
>> Semi-major axis
>> Projection UTM MGA Z 53
>> Central meridian 135 E
>> False E/N, Scale factor 0.9996 etc
>>
>>
> I would simply use: invproj -W2 +proj=utm +zone=53 +south +ellps=GRS80
>
> Other parameters like central meridian, scale factor, etc. do not need to
> be specified explicitly. They are implied through +proj=utm and +zone=53.
>
>
> Hermann
>
>
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