[Qgis-user] Projection of Shapefile export

[Brett Adams]

/Actually, this is worse than I thought. QGIS is not recognising AGD84 
or GDA94. The data comes in but isn't attributed a CRS so defaults to WGS84.
If you import the text file as AGD84, then again as GDA94, there should 
be approx 195m separation. QGIS plots them in exactly the same place. /
>
>>  Micha,
>> Sorry but I can't get your suggestions to work. I tried this a couple 
>> of times but it fails every time.
>>
>> Settings->Options-CRS window is already set to "Prompt for CRS"
> And when you next import the csv, does it indeed prompt for the CRS? 
> /It does. But when I go to Settings>>Project properties the CRS is WGS84./

>>
>> Tried changing the global to AGD84 / AMG zone 51, when I reopen the 
>> window its set to AGD66 so this setting is not holding.
> Weird. There's no permissions problems? /Not that I'm aware of. It 
> gives me no complaints
> /

>>
>> When I reimport the the CSV file the default is still WGS84, despite 
>> the global been set to AGD84 (or is it AGD66, I can't be sure). Again 
>> I select AGD84.
>>
>> Layer > Properties > Specify CRS comes up as AGD66. Changed it to AGD84
>>
>> When I export the layer, I'm again asked to specify the projection, 
>> AGD84
>>
>> Exported *.prj file still has a datum of "D_unknown". Upon import of 
>> the shape file, my version of QGIS will now default this to AGD84 
>> however as the *.prj file is wrong it no good to anyone else.
> Here's the prj that I'm getting:
>
> PROJCS["UTM Zone 51, Southern Hemisphere",GEOGCS["Australian Natl & S. 
> Amer. 1969",DATUM["D_unknown",SPHEROID["aust_SA",6    
> 378160,298.25]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["l    
> atitude_of_origin",0],PARAMETER["central_meridian",123],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000    
> ],PARAMETER["false_northing",10000000],UNIT["Meter",1]]
>
> What should it be? Even tho' it's called "D_unknown" all the 
> parameters seem to be there.
/
PRJ file should be something like below. /

PROJCS["AGD84 / AMG zone 
51",GEOGCS["AGD84",DATUM["D_Australian_1984",SPHEROID["Australian_National_Spheroid",6378160,298.25]],PRIMEM["Greenwich",0],
UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",117],
PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",10000000],UNIT["Meter",1]]
>
>>
>>
>>
>> The only real work around I have so far is to delete the *.prj file 
>> and then specify the projection on import.
>>
>>
>>
>>
>> On 19/09/2010 2:35 PM, Micha Silver wrote:
>>> Micha Silver wrote:
>>>
>>>> Brett Adams wrote:
>>>>
>>>>> Micha,
>>>>> I've attached csv data for importing and all shape files exported. 
>>>>> I've added comments into your prior email also.
>>>>>
>>>> Hi Brett:
>>>>
>>>> I do indeed see a problem exporting to the AGD84 CRS. I get a 
>>>> "Latitude or Longitude exceeds limits" error. This happens when the 
>>>> global CRS is set to WGS84 (which is the default in QGIS). Attached 
>>>> is a screen shot of the error.
>>>>
>>>> Here's how to overcome the problem: Change your Global CRS to AGD84 
>>>> zone 51 (BTW, that's EPSG code 20351). This is done in the 
>>>> Settings->Options->CRS dialog window. Now re-import the csv file 
>>>> and then save as shapefile and you should be able to select the 
>>>> AGD84 CRS and have it saved correctly.
>>>> Alternatively, if you don't want to change the global CRS setting, 
>>>> you can select (in the same Settings->Options-CRS window) to 
>>>> "Prompt for CRS".  Then when you import the csv you'll be asked to 
>>>> specify the correct CRS for the points, You again select AGD84 and 
>>>> all should be well.
>>>>
>>>> Cheers,
>>>> Micha
>>>>
>>> And just to complete the picture, Jurgen reminded me that in recent 
>>> versions there's a setting for each layer to set what CRS it is. 
>>> This is found in the Layer->properties window, General tab. Click on 
>>> the button "Specify CRS" and choose the correct coordinate system. 
>>> You can do this also for a delimited text file layer.  Then export 
>>> to shapefile works as you'd expect..
>>
>>
>


-- 
Brett Adams
Spinifex Geophysics
0438 861 974
SKYPE:brettadams_spinifex

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