mapscript API shapfileObj units

[Stephen Woodbridge]

Well, I will defer to Frank on this, but my guess is that he is reading 
and parsing the *.prj file associated to the shapefile by its basename. 
This is in fact totally ignored by mapserver and therefore mapscript.

So if you have these files and what to pull info from them, then just 
open them as text file and read them in and parse the strings to get the 
info.

-Steve W

Kralidis,Tom [Burlington] wrote:
> Thanks for the info.
> 
> Having said this, if I do an ogrinfo, for example, on a shapefile, I do
> get some units info returned, i.e.:
> 
> $ ogrinfo -al -summary ~tkralidi/geos/data/Confederation_Trail_2005.shp
> INFO: Open of `/home/tkralidi/geos/data/Confederation_Trail_2005.shp'
> using driver `ESRI Shapefile' successful.
> 
> Layer name: Confederation_Trail_2005
> Geometry: Line String
> Feature Count: 601
> Extent: (305059.000053, 657304.420162) - (471874.599925, 767349.092887)
> Layer SRS WKT:
> PROJCS["PEI NAD83",
>     GEOGCS["GCS_North_American_1983_CSRS98",
>         DATUM["NAD83_Canadian_Spatial_Reference_System",
>             SPHEROID["GRS_1980",6378137.0,298.257222101]],
>         PRIMEM["Greenwich",0.0],
>         UNIT["Degree",0.0174532925199433]],
>     PROJECTION["Double_Stereographic"],
>     PARAMETER["False_Easting",400000.0],
>     PARAMETER["False_Northing",800000.0],
>     PARAMETER["Central_Meridian",-63.0],
>     PARAMETER["Scale_Factor",0.999912],
>     PARAMETER["Latitude_Of_Origin",47.25],
>     UNIT["Meter",1.0]]
> NAME: String (12.0)
> INDEX: String (12.0)
> </snip>
> 
> ...so I initially imagine that this could be marshalled into
> shapefileObj.
> 
> ..Tom
> 
>  
> 
>> -----Original Message-----
>> From: Stephen Woodbridge [mailto:woodbri at swoodbridge.com] 
>> Sent: 30 October, 2006 1:14 PM
>> To: Kralidis,Tom [Burlington]
>> Cc: MAPSERVER-USERS at LISTS.UMN.EDU
>> Subject: Re: [UMN_MAPSERVER-USERS] mapscript API shapfileObj units
>>
>> You can't! This is because it is not encoded in the shapefile 
>> to start with. The only reason you can get it from the Layer 
>> pbject is because you can set it in the mapfile and then 
>> retrieve it layer into mapscript. 
>> The equivalent behavior would be to create a metadata file 
>> for each shapefile and fetch it from that.
>>
>> -Steve
>>
>> Kralidis,Tom [Burlington] wrote:
>>> Hi,
>>>
>>> We have a script which utilizes the new mapscript geos 
>> functionality 
>>> by applying a buffer to each shapeObj within a shapefileObj 
>> to output 
>>> a new dataset.
>>>
>>> My question is I would like to know the units of shapefileObj (or 
>>> shapeObj).
>>>
>>> The mapscript API has layerObj->{units} as a property, but I am not 
>>> working within the layerObj context (i.e. I am not working on 
>>> mapfiles, just datasets).
>>>
>>> Any idea on how to fetch this info from the mapscript API without 
>>> layerObj?  I've skimmed through 
>>> http://mapserver.gis.umn.edu/docs/reference/mapscript/index_html as 
>>> part of my investigation, but didn't find anything else (or 
>> course I 
>>> may have glossed over something -- happens to me often!).
>>>
>>> Thanks
>>>
>>> ..Tom
>>