[postgis-devel] Adding Functions w/o Adding

[Nicklas Avén]

Hallo I have thought that I should raise some ideas about the line reference functions after this release. I mention it noe because it is a close subject. I would like to rewrite the linereferencing functions like ST_Line_Substring to do the measure in all 3 dimensions. I am not sure I suggest that there should be a different behaviour in that function but rather make a new that also handles the measure in units like meters instead of parts of the whole line.
 
But the thing that was connected to this question was this about measuring in 2 or three dimensions. Does this customer wants it in 2D measuring or will he or she only work in 2 D so it doesn't matter. 
 
What I mean is that if we want to go against 3Dmeasuring at line referencing maybe that should be included in the bbeginning on this one?
 
Just a thought.
 
What is needed as I understands it is just another function like distance3d_pt_pt that uses 3 dimensions in pythagora theorem.
 
In this function it would not matter that is only following the ground or a line that has the same angel to the ground all the way. But it would be a difference on a line following the ground and then suddenly continuing ut on a mountain or something like that.
Just a thought
 
/Nicklas
2010-01-22 Paul Ramsey wrote:

All,
>
>I have a client who needs a custom function added. Since we're well into release, obviously the SQL API can't change, or really any code in underneath any existing SQL functions. 
>However, I can implement the function as a completely additive thing (and in fact have), so it affects the stability of existing functions not at all. And I can leave the SQL API alone, and simple ship the CREATE FUNCTION code directly to the client. 
>
>http://trac.osgeo.org/postgis/attachment/ticket/390/addmeasure.patch
>
>They get the benefit of a quick turnaround on a new feature, we maintain our contract with respect to leaving the API unchanged through minor releases.
>I'd like to apply this patch into stable branches so folks who want it can have it, by running the CREATE FUNCTION code themselves.
>
>Paul
>
>--
>Paul Ramsey
>OpenGeo - http://opengeo.org
>The secret sauce is called... PostGIS.
>
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