[Gdal-dev] crash on blank lines in .prj / ESRI TM params

[Chapman, Martin]

Mike,
 
Thanks for the info.  I thought it might be an older format after I sent the email.  Sorry for the assumption.
 
Martin

	-----Original Message----- 
	From: Global Mapper Support [mailto:support at globalmapper.com] 
	Sent: Mon 2/14/2005 9:31 PM 
	To: Chapman, Martin; 'Ben Discoe'; gdal-dev at remotesensing.org 
	Cc: 
	Subject: RE: [Gdal-dev] crash on blank lines in .prj / ESRI TM params
	
	

	Martin/Ben,
	
	The .prj file that Ben provided is an older format ESRI .prj file. With the
	ArcView v8 (I think) release, ESRI switched to the format of PRJ files that
	you attached.
	
	As for the blank lines and the ordering of the parameters, I've never
	personally seen any kind of standard document describing the old .prj
	format, so my coding of the creation of those files is entirely based upon
	samples that I've seen. It seems that about half of the sample files that I
	have do have a blank line between parameters and half don't. I don't know if
	some programs will break on .prj files with no blank lines or not, it seems
	best if OGR can handle the blank lines gracefully since there are lots of
	them out there from sources other than Global Mapper.
	
	I don't know if there is a standard order for the projection parameters
	either, Global Mapper parses the comment after the parameter to determine
	what the value is, thereby making it independent of any ordering.
	
	Mike
	Global Mapper Support
	support at globalmapper.com
	
	-----Original Message-----
	From: Chapman, Martin [mailto:MChapman at sanz.com]
	Sent: Monday, February 14, 2005 9:42 PM
	To: Ben Discoe; gdal-dev at remotesensing.org
	Cc: support at globalmapper.com
	Subject: RE: [Gdal-dev] crash on blank lines in .prj / ESRI TM params
	
	Ben,
	
	That file doesn't look like an esri prj file.  Attached is what esri looks
	like.  I think the style is called something like baucus-nor or something.
	It's similiar to an ogc wks.
	
	Martin
	
	        -----Original Message-----
	        From: Ben Discoe [mailto:ben at vterrain.org]
	        Sent: Mon 2/14/2005 8:36 PM
	        To: gdal-dev at remotesensing.org
	        Cc: support at globalmapper.com
	        Subject: [Gdal-dev] crash on blank lines in .prj / ESRI TM params
	       
	       
	
	
	        I noticed this evening that OGR will crash if asked to parse an
	ESRI-style
	        .prj file with some extra whitespace.  Attached is an example, which
	was
	        output from the software 'Global Mapper' (GM).
	       
	        I've cc'd GM's author, so he can address the extra LF characters,
	but it
	        would also be good to make OGR a little more robust.  The problem
	appears to
	        be an if/else in OSR_GDV (ogr_srs_esri.cpp) which doesn't check for
	an empty
	        parameter.  The problem is probably in the calling code though
	        (importFromESRI) which is making the assumption.
	       
	        Even when the extra LF are removed, there is a second problem: OGR
	is
	        expecting the parameters for TM projections in this order:
	        1. Scale
	        2. CenterLat (latitude of the origin)
	        3. CenterLong (central meridian)
	        4. FalseEasting
	        5. FalseNorthing
	       
	        But GM is writing them in a slightly different order:
	        1. Scale
	        2. CenterLong (central meridian)
	        3. CenterLat (latitude of the origin)
	        4. FalseEasting
	        5. FalseNorthing
	       
	        It seems reasonable to conclude that one of these (OGR or GM) is
	        wrong/non-standard.
	       
	        -Ben