Hi Guillaume, - about the API, I have created new thread https://groups.google.com/forum/#!topic/otb-developers/Pps8mmbHe80 ... where I have just put some example of how the proposed API should work... I do not want to create C++ application connecting to DB through GDAL or other driver, getting data, processing with OTB and upload results back. I would like to call OTB processing functions directly on data stored in PostGIS using PostgreSQL backend - about LSMS performance... I have found in [1], Table I, that non-linearity in processing time vs. image size is reported there. Could you be more specific, what you mean with "improve the situation with the parameters exposed in the application"? I am thinking about asking new question in otb-users mail list just to cover how to use LSMS step 1 on large rasters, but I would like to make some test before... Thank you very much for your suggestions, J.
[1] http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6849524&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel7%2F36%2F4358825%2F06849524.pdf%3Farnumber%3D6849524 Dne středa 10. srpna 2016 11:57:54 UTC+2 Guillaume Pasero napsal(a): > > Hi, > > In OTB, almost every image is opened using GDAL. If you manage to have > GDAL reading from a PostGIS database, it should be transparent on OTB side. > > More information here: > https://trac.osgeo.org/gdal/wiki/frmts_wtkraster.html > <https://www.google.com/url?q=https%3A%2F%2Ftrac.osgeo.org%2Fgdal%2Fwiki%2Ffrmts_wtkraster.html&sa=D&sntz=1&usg=AFQjCNGamMmlq3pNqJ2ntb8Wi6rnALj9gQ> > The same goes for the shape->PostGIS, if you can directly output the > vector segmentation in a PostGIS table, it should be faster. ( > http://www.gdal.org/drv_pg.html) > > About the LSMS Smoothing performance, there may be a way to improve the > situation with the parameters exposed in the application. > > Regards, > Guillaume > > On 07/28/2016 09:11 AM, Jiří Fejfar wrote: > > Hi all, > > I am performing segmentation on many Landsat8 scenes stored in PostgreSQL > / PostGIS. I have a very sub-optimal work-flow (all is done in Python > script on server side): > > - export tiled raster from PostGIS to .tiff image > - perform 4 steps of LSMS > > <http://otbcb.readthedocs.io/en/latest/Applications/app_LSMSSegmentation.html> > > segmentation using python API resulting in .shp with segments > - import this with shp2pgsql back to table in PostGIS. > > Although this is working it has several drawbacks > > - I have found that first step of LSMS > > <http://otbcb.readthedocs.io/en/latest/Applications/app_MeanShiftSmoothing.html> > > is not linear regarding elapsed time and amount of data (see attached > image) ... I have found not possible to process with this step whole > Landsat8 scene, so I am doing whole before-mentioned pipeline in cycle > processing 5 rows (1 consists from tiles of the size 128 x 128 px) loosing > advantage of artifacts free result. > > > > <https://lh3.googleusercontent.com/-OZSbkwJOu38/V5mtarcKdfI/AAAAAAAAEZE/e5m8AY74Y0gXs9cfmsOmjLSbXsfDReROQCLcB/s1600/rows_vs_time.jpg> > > - I believe it can be much faster. > > > Because of that I am trying to find the way, how to pass tiled image from > PostgreSQL directly to OTB... I have found > http://wiki.orfeo-toolbox.org/index.php/OTB-PostGIS_Interface but it > seems to be focused opposite way: expose PostGIS functionality to OTB. I > would like to expose OTB functionality (actually only LSMS 4 steps) > directly to PostGIS. > > > Do you know such existing API? > > > If there is no such API, I would like to contribute to that. I have > experience creating API exposing C++ classes / functions to PostgreSQL like > described in 35.9.13. Using C++ for Extensibility. > <https://www.postgresql.org/docs/9.4/static/xfunc-c.html> > > > Best regards, Jiří. > -- > -- > Check the OTB FAQ at > http://www.orfeo-toolbox.org/FAQ.html > > You received this message because you are subscribed to the Google > Groups "otb-users" group. > To post to this group, send email to [email protected] > <javascript:> > To unsubscribe from this group, send email to > [email protected] <javascript:> > For more options, visit this group at > http://groups.google.com/group/otb-users?hl=en > --- > You received this message because you are subscribed to the Google Groups > "otb-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > > -- > <http://www.c-s.fr> *Guillaume PASERO* > Responsable technique > *Business Unit E-SPACE & Geo Information - Département Image & > Applications* > > *CS Systèmes d'Information* > Parc de la Grande Plaine - 5, Rue Brindejonc des Moulinais - BP 15872 > 31506 Toulouse Cedex 05 - FRANCE > +33 561 17 64 21 - [email protected] <javascript:> > -- -- Check the OTB FAQ at http://www.orfeo-toolbox.org/FAQ.html You received this message because you are subscribed to the Google Groups "otb-users" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/otb-users?hl=en --- You received this message because you are subscribed to the Google Groups "otb-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
