[postgis] How to interpret geometry from binary cursor?

[Paul Ramsey]

Check out the example WKB program in examples. That is our one piece of
prototype code on reading from the binary cursor. It is not well
documented in general in the pgsql docs. Dave can give some more
pointers. I am guessing you might want to be pulling the objects out
directly, not even as WKB. This is not normally suggested behavior, but
you have special requirements, if I am not mistaken.

If you figure it all out, you could always write the documentation
section :)

Paul

"Petri J. Riipinen" wrote:
> 
> Hi folks,
> 
> I would like to use a binary cursor to fetch geometry information from a
> database, that has been created with shp2pgsql, i.e. there is the
> 'the_geom'-field that contains the information.
> 
> What is the format of the binary buffer, if I use binary cursor to retrieve
> the value from 'the_geom'-field?
> 
> For example, if I get this:
> ---------------
> SRID=-1;MULTILINESTRING((3330551.305 6826440.643,3330557.168
> 6826456.235,3330557.133 6826462.116,3330555.755 6826468.43,3330552.952
> 6826473.407,3330517.697 6826535.548,3330515.897 6826542.503,3330514.544
> 6826564.475,3330521.949 6826581.788,3330519.45 6826590.306,3330488.713
> 6826603.744,3330483.613 6826604.059,3330473.991 6826606.385,3330469.262
> 6826609.178,3330456.215 6826618.894,3330452.556 6826623.097,3330447.507
> 6826631.63,3330441.956 6826639.104,3330437.015 6826642.11,3330431.789
> 6826644.905,3330425.858 6826648.13,3330417.734 6826652.077,3330402.773
> 6826661.804,3330385.44 6826677.428,3330360.307 6826703.657,3330340.441
> 6826722.803,3330330.563 6826732.363,3330320.428 6826745.113,3330298.189
> 6826769.511,3330284.102 6826789.787,3330277.665 6826802.316,3330276.836
> 6826807.835,3330278.699 6826816.728,3330309.72 6826837.432,3330335.862
> 6826847.397,3330351.446 6826851.637,3330370.24 6826855.572,3330387.627
> 6826860,3330400.393 6826862.117,3330421.401 6826861.768))
> ---------------
> 
>  From 'SELECT * FROM ROADS'.... where 'the_geom' is just one field among
> other fields.
> 
> How would I interpret the binary cursor value for that field?
> 
> - Petri
> 
> PS. I guess this is something that would be in PostGIS manual, but at the
> moment the section for Binary cursors is empty...:(
> <><><><><><><><>
>    Petri J. Riipinen
> petri.riipinen at nic.fi
> <><><><><><><><>
> 
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> 
> 
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     | Paul Ramsey
     | Refractions Research
     | Email: pramsey at refractions.net
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