[Qgis-developer] Creating a new raster qith QgsRasterLayer?
Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
Thanks Radim, I wasn't aware of all these news in trunk! The QgsRasterPipe is really powerful. Is there some doc about it? I've run through the code to understand the logic behind QgsRasterPipe (QRP) and QgsRasterInterface (QRI). I see that for a QRI must be set a an input QRI (setInput method). If I understand it correctly a QRP can have various branches made by sequences of QRI? giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
On Tue, Dec 11, 2012 at 12:23 PM, G. Allegri gioha...@gmail.com wrote: Thanks Radim, I wasn't aware of all these news in trunk! The QgsRasterPipe is really powerful. Is there some doc about it? I've run through the code to understand the logic behind QgsRasterPipe (QRP) and QgsRasterInterface (QRI). I see that for a QRI must be set a an input QRI (setInput method). If I understand it correctly a QRP can have various branches made by sequences of QRI? Do you mean QgsRasterInterface with multiple inputs? This is not currently supported. In theory you can write an interface with multiple inputs, but for example QgsRasterFileWriter is using some info from srcInput, i.e. the first interface (provider) in the pipe, there is no support for multiple srcInput. Most probably it would work, but there some problems may appear. You could also overwrite srcInput in your QgsRasterInterface subclass in which multiple branches are connected. Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
Do you mean QgsRasterInterface with multiple inputs? This is not currently supported. In theory you can write an interface with multiple inputs, but for example QgsRasterFileWriter is using some info from srcInput, i.e. the first interface (provider) in the pipe, there is no support for multiple srcInput. Most probably it would work, but there some problems may appear. You could also overwrite srcInput in your QgsRasterInterface subclass in which multiple branches are connected. Ok, but I wonder what is QgsRasterInterface.setInput [1] meant for? Is the input supposed to be only a QgsRasterDataProvider? If I see that it requires a QgsRasterInterface I think it can be whatever else QgsRasterInterface... [1] https://github.com/qgis/Quantum-GIS/blob/master/src/core/raster/qgsrasterinterface.h#L108 Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
On Tue, Dec 11, 2012 at 1:29 PM, G. Allegri gioha...@gmail.com wrote: Do you mean QgsRasterInterface with multiple inputs? This is not currently supported. In theory you can write an interface with multiple inputs, but for example QgsRasterFileWriter is using some info from srcInput, i.e. the first interface (provider) in the pipe, there is no support for multiple srcInput. Most probably it would work, but there some problems may appear. You could also overwrite srcInput in your QgsRasterInterface subclass in which multiple branches are connected. Ok, but I wonder what is QgsRasterInterface.setInput [1] meant for? Is the input supposed to be only a QgsRasterDataProvider? If I see that it requires a QgsRasterInterface I think it can be whatever else QgsRasterInterface... Yes, you are right. Any class inheriting from QgsRasterInterface may be plugged into the QgsRasterPipe but all interfaces will be in a single line, no forks. BTW, you should always test if QgsRasterPipe::insert() was successful, because if connection of interfaces fails, the interface is not inserted. Only compatible interfaces may be connected. For example, it is not possible to connect QgsSingleBandGrayRenderer to an interface of ARGB32 type, because it needs numerical data as input. QgsRasterResampleFilter only works with ARGB32 as input etc. Radim [1] https://github.com/qgis/Quantum-GIS/blob/master/src/core/raster/qgsrasterinterface.h#L108 Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
Yes, you are right. Any class inheriting from QgsRasterInterface may be plugged into the QgsRasterPipe but all interfaces will be in a single line, no forks. Ok, Radim, I'm sorry if I insist on this, it's just to understand it correctly. To add a QgsRasterInterface in a QgsRasterPipe I would use QgsRasterPipe.insert(idx,QgsRasterInterface), but what is the QgsRasterInterface.setInput(QgsRasterInterface ) for? If I set a QgsRasterInterface, which will have its own input, as the input for another QgsRasterInterface, I'm creating a chain of QgsRasterInterfaces... Help me to understand it... giovanni BTW, you should always test if QgsRasterPipe::insert() was successful, because if connection of interfaces fails, the interface is not inserted. Only compatible interfaces may be connected. For example, it is not possible to connect QgsSingleBandGrayRenderer to an interface of ARGB32 type, because it needs numerical data as input. QgsRasterResampleFilter only works with ARGB32 as input etc. Radim [1] https://github.com/qgis/Quantum-GIS/blob/master/src/core/raster/qgsrasterinterface.h#L108 Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
On Tue, Dec 11, 2012 at 2:23 PM, G. Allegri gioha...@gmail.com wrote: Yes, you are right. Any class inheriting from QgsRasterInterface may be plugged into the QgsRasterPipe but all interfaces will be in a single line, no forks. Ok, Radim, I'm sorry if I insist on this, it's just to understand it correctly. To add a QgsRasterInterface in a QgsRasterPipe I would use QgsRasterPipe.insert(idx,QgsRasterInterface), but what is the QgsRasterInterface.setInput(QgsRasterInterface ) for? QgsRasterInterface.setInput(QgsRasterInterface ) is used to set input, but you dont have to call it if you are using QgsRasterPipe because it is called by QgsRasterPipe.insert(idx,QgsRasterInterface). If I set a QgsRasterInterface, which will have its own input, as the input for another QgsRasterInterface, I'm creating a chain of QgsRasterInterfaces... Yes, QgsRasterPipe just helps you to manage such chain. It will automatically connect the interfaces. QgsRasterPipe represents a chain of interfaces. Radim Help me to understand it... giovanni BTW, you should always test if QgsRasterPipe::insert() was successful, because if connection of interfaces fails, the interface is not inserted. Only compatible interfaces may be connected. For example, it is not possible to connect QgsSingleBandGrayRenderer to an interface of ARGB32 type, because it needs numerical data as input. QgsRasterResampleFilter only works with ARGB32 as input etc. Radim [1] https://github.com/qgis/Quantum-GIS/blob/master/src/core/raster/qgsrasterinterface.h#L108 Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Creating a new raster qith QgsRasterLayer?
Ok, perfect, now it's clear. giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 2:23 PM, G. Allegri gioha...@gmail.com wrote: Yes, you are right. Any class inheriting from QgsRasterInterface may be plugged into the QgsRasterPipe but all interfaces will be in a single line, no forks. Ok, Radim, I'm sorry if I insist on this, it's just to understand it correctly. To add a QgsRasterInterface in a QgsRasterPipe I would use QgsRasterPipe.insert(idx,QgsRasterInterface), but what is the QgsRasterInterface.setInput(QgsRasterInterface ) for? QgsRasterInterface.setInput(QgsRasterInterface ) is used to set input, but you dont have to call it if you are using QgsRasterPipe because it is called by QgsRasterPipe.insert(idx,QgsRasterInterface). If I set a QgsRasterInterface, which will have its own input, as the input for another QgsRasterInterface, I'm creating a chain of QgsRasterInterfaces... Yes, QgsRasterPipe just helps you to manage such chain. It will automatically connect the interfaces. QgsRasterPipe represents a chain of interfaces. Radim Help me to understand it... giovanni BTW, you should always test if QgsRasterPipe::insert() was successful, because if connection of interfaces fails, the interface is not inserted. Only compatible interfaces may be connected. For example, it is not possible to connect QgsSingleBandGrayRenderer to an interface of ARGB32 type, because it needs numerical data as input. QgsRasterResampleFilter only works with ARGB32 as input etc. Radim [1] https://github.com/qgis/Quantum-GIS/blob/master/src/core/raster/qgsrasterinterface.h#L108 Radim giovanni 2012/12/11 Radim Blazek radim.bla...@gmail.com On Tue, Dec 11, 2012 at 10:52 AM, G. Allegri gioha...@gmail.com wrote: Until now I've mostly created vector layers on QGIS, delegating raster creation to custom GDAL utilities. Recently I looked into QgsGdalProvider and I saw that it exposes the QgsRasterDataProvider::Create capability. I wonder if it's possible to create a brand new raster (geotiff or what else) using this provider and, in case, what is the right workflow to do that. I haven't found examples of doing it... Yes it is possible. You can use a provider directly QgsRasterDataProvider * provider = ( QgsRasterDataProvider* )QgsProviderRegistry::instance()-provider( gdal, dataSource ); provider-write( data, band, width, height, xOffset, yOffset ) if you your algorithm implemented as QgsRasterInterface you can use higher level QgsRasterFileWriter which will do the work splitting raster into parts QgsRasterPipe* pipe = new QgsRasterPipe(); pipe-set( inputProvider-clone() ); pipe-insert( 1, yourInterface ); QgsRasterFileWriter fileWriter( fileName ); fileWriter.writeRaster( pipe, width, height, extent, crs ); Radim giovanni ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
