[gdal-dev] GSOC 2015 proposal - Integration of cpp GDAL utilities into GDAL core library

[Daniel Morissette]

+1 to Even's explanation on why this would be a very welcome addition.

We should also add to the requirements a refactoring of the "complex 
code" to  structure the messages/information that is currently output to 
stdout by the command-line utilities so that the calling program can 
interpret and present that info to the end user in a meaningful way.

Daniel


On 2015-03-27 4:08 PM, Even Rouault wrote:
> Peter,
>
>> Maybe I've missed the point (through over familiarity with GDAL/OGR?)
>> .... but these utilities were originally branded as 'worked examples'
>> of how to use the substantive libraries to perform well understood
>> operations from which usage of the libraries might be readily
>> understood.  Each utility is itself a commented set of function calls
>> to the relevent GDAL libraries.
>
> There is non trivial logic involved in some of the utilities (e.g. ogr2ogr)
> and people have the choice between :
> - doing a system call ("ogr2ogr ...."), but this isn't practical to deal with
> progress report, cancellation, or operating on in-memory datasets
> - copy&pasting the source code of the utility in their own code, and
> "librarify'ing" it to remove exit(), etc...
> - learning the GDAL/OGR API to do their own custom processing chain. More
> powerfull but longer learning curve
>
> So the interest of the project would be to make life easier for people using
> the first 2 bullets (and I can tell you that there are a lot of people hitting
> those 2 bullets)
>
>> Why is there a need to duplicate this
>> in turning the utilities into function calls which then, in turn, must
>> be called by new stand-alone utilities?
>> There has to be a loss of
>> efficiency in sunch a process.
>
> I don't think there will be a loss of efficiency
>
> Instead of ogr2ogr.cpp being currently
>
> int main(...)
> {
> 	complex_code
> }
>
> you would have (very schematically)
>
> ogr2ogr.cpp:
>
> int main(...)
> {
>         ogr2ogr_options = parse aguments()
>         return ogr2ogr(ogr2ogr_options)
> }
>
> and libgdalutils_ogr2ogr.cpp :
>
> int ogr2ogr(ogr2ogr_options)
> {
>       complex_code (moved from currently existing main)
> }
>
> Even
>


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Daniel Morissette
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