Re: [Qgis-developer] show grid on map canvas (similiar to grid used in composer) - strategy?
I wonder if http://grass.osgeo.org/wiki/Ps.output might give good ideas for drawing a grid on the map canvas. On Wed, May 9, 2012 at 2:00 PM, Etienne Tourigny wrote: > Hi all, > > I would like to add support to draw a grid on the map canvas, in a way > similar to what is done in the map composer (although perhaps without > the annotations on the borders). > > What should be the approach used? > > 1) plugin or core? > 2) rubberbands or basic plot functions triggered after mapCanvas update? > > I think both drawing strategies are possible using a plugin. > > It would be best to write in the core, assuming there is sufficient > interest in this, but it will take time to trickle down to the stable > version (an argument for making it a plugin). > > I know the current workaround is to create a vector grid with ftools, > but that is a little clunky. > > Any thoughts? > Etienne > ___ > 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
[Qgis-developer] Re: show grid on map canvas (similiar to grid used in composer) - strategy?
Hi folks, there have been a number of interesting suggestions, I will try to summarize them this week. I quickly put together a basic grid in the main map canvas, using the interface and logic from the map composer. I have decided to implement the grid as a decoration and accordingly added an item to the Decoration menu. I have also improved the decorations management to be able to draw the decorations in a particular order (with a new class QgsDecorationItem), so that other decorations are on top of the grid. There is support for grid annotations, but only inside the map border currently. Line symbology is still basic (line width+color). Basically I think there could be 2 concurrent and complementary ways to implement grids: 1) basic grid in core, similar to what is already in the composer map (and in my branch) 2) more refined grid(s) as plugin/vector layers, whose rendering order can be fine-tuned Those interested can have a look at my github branch: https://github.com/etiennesky/Quantum-GIS/tree/decorationgrid Etienne On Wed, May 9, 2012 at 6:00 PM, Etienne Tourigny wrote: > Hi all, > > I would like to add support to draw a grid on the map canvas, in a way > similar to what is done in the map composer (although perhaps without > the annotations on the borders). > > What should be the approach used? > > 1) plugin or core? > 2) rubberbands or basic plot functions triggered after mapCanvas update? > > I think both drawing strategies are possible using a plugin. > > It would be best to write in the core, assuming there is sufficient > interest in this, but it will take time to trickle down to the stable > version (an argument for making it a plugin). > > I know the current workaround is to create a vector grid with ftools, > but that is a little clunky. > > Any thoughts? > Etienne ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Fwd: Threads in sextante
Victor, I agree on all your points. May I suggest to have a unique interface/approach that other existing interfaces can benefit from (i.e. standalone gdaltools and ftools). It seems that QProcess is an interesting candidate (and QThread when not using external app.), because it works in both c++ and in pyqt (ref. gdaltools) - plus there is already code inside qgis that uses it. my 2 centavos Etienne On Sun, May 13, 2012 at 6:13 PM, Victor Olaya wrote: > Here is my opinion on all that, in short: > > -The main idea of using threads is not now to execute multiplep > algorithms at the same time, so we can remove a lot of complexity > (like 2 processes writing the same file, as it was mentioned) > > -Implementing a canceling mechanism is going to be the greatest > improvement once we have the threading stuff > > -So, for me, this is what should be done: > > 1)implementing the threading part > 2) implement the cancelling mechanism (a responsive cancel button, etc) > 3) modifying algorithm to respond to cancellin events. > > I think that would be more than enough for a first part, and it would > be a great improvement for SEXTANTE > > Regards > > p.s. Just to let you know, I am leaving for Honduras tomorrow, and > will be there working for 2 weeks, so I not might be very active on > the lists during the next 15 days or so > > 2012/5/13 Marco Hugentobler : >> Hi Alex >> >> >>>Also I think about rewritting fTools in C++ and integrating its >>>algorithms into QGIS >>>analysis library. This makes tools a bit faster and will allow to use >>>algorithms in >>>plugins >> >> That would be a great enhancement and leverage the analysis library as a >> whole. >> >> Regards, >> Marco >> >> >> >> >> On 13.05.2012 09:23, Alexander Bruy wrote: >>> >>> Hi Etienne, >>> >>> 2012/5/12 Etienne Tourigny: I stand corrected then - I guess I was confusing it with ftools, which is blocking and does not spawn a process. Any way ftools could be adapted to use the same approach as gdaltools? >>> >>> most fTools functions already implemented as threaded, but there are some >>> minor issues. I work on improving processes handing in fTools, and several >>> tools already don't block main QGIS window, has non-modal dialogs and >>> allows >>> to cancel running process. >>> >>> Also I think about rewritting fTools in C++ and integrating its >>> algorithms into QGIS >>> analysis library. This makes tools a bit faster and will allow to use >>> algorithms in >>> plugins >>> >> >> >> -- >> Dr. Marco Hugentobler >> Sourcepole - Linux& Open Source Solutions >> Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland >> marco.hugentob...@sourcepole.ch http://www.sourcepole.ch >> Technical Advisor QGIS Project Steering Committee >> >> >> ___ >> 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 ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Fwd: Threads in sextante
Here is my opinion on all that, in short: -The main idea of using threads is not now to execute multiplep algorithms at the same time, so we can remove a lot of complexity (like 2 processes writing the same file, as it was mentioned) -Implementing a canceling mechanism is going to be the greatest improvement once we have the threading stuff -So, for me, this is what should be done: 1)implementing the threading part 2) implement the cancelling mechanism (a responsive cancel button, etc) 3) modifying algorithm to respond to cancellin events. I think that would be more than enough for a first part, and it would be a great improvement for SEXTANTE Regards p.s. Just to let you know, I am leaving for Honduras tomorrow, and will be there working for 2 weeks, so I not might be very active on the lists during the next 15 days or so 2012/5/13 Marco Hugentobler : > Hi Alex > > >>Also I think about rewritting fTools in C++ and integrating its >>algorithms into QGIS >>analysis library. This makes tools a bit faster and will allow to use >>algorithms in >>plugins > > That would be a great enhancement and leverage the analysis library as a > whole. > > Regards, > Marco > > > > > On 13.05.2012 09:23, Alexander Bruy wrote: >> >> Hi Etienne, >> >> 2012/5/12 Etienne Tourigny: >>> >>> I stand corrected then - I guess I was confusing it with ftools, which >>> is blocking and does not spawn a process. >>> Any way ftools could be adapted to use the same approach as gdaltools? >> >> most fTools functions already implemented as threaded, but there are some >> minor issues. I work on improving processes handing in fTools, and several >> tools already don't block main QGIS window, has non-modal dialogs and >> allows >> to cancel running process. >> >> Also I think about rewritting fTools in C++ and integrating its >> algorithms into QGIS >> analysis library. This makes tools a bit faster and will allow to use >> algorithms in >> plugins >> > > > -- > Dr. Marco Hugentobler > Sourcepole - Linux& Open Source Solutions > Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland > marco.hugentob...@sourcepole.ch http://www.sourcepole.ch > Technical Advisor QGIS Project Steering Committee > > > ___ > 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] Fwd: Threads in sextante
Hi Alex >Also I think about rewritting fTools in C++ and integrating its >algorithms into QGIS >analysis library. This makes tools a bit faster and will allow to use >algorithms in >plugins That would be a great enhancement and leverage the analysis library as a whole. Regards, Marco On 13.05.2012 09:23, Alexander Bruy wrote: Hi Etienne, 2012/5/12 Etienne Tourigny: I stand corrected then - I guess I was confusing it with ftools, which is blocking and does not spawn a process. Any way ftools could be adapted to use the same approach as gdaltools? most fTools functions already implemented as threaded, but there are some minor issues. I work on improving processes handing in fTools, and several tools already don't block main QGIS window, has non-modal dialogs and allows to cancel running process. Also I think about rewritting fTools in C++ and integrating its algorithms into QGIS analysis library. This makes tools a bit faster and will allow to use algorithms in plugins -- Dr. Marco Hugentobler Sourcepole - Linux& Open Source Solutions Churerstrasse 22, CH-8808 Pfäffikon SZ, Switzerland marco.hugentob...@sourcepole.ch http://www.sourcepole.ch Technical Advisor QGIS Project Steering Committee ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
[Qgis-developer] Re: Welcome to 4 QGIS students in Google Summer of Code 2012
Hello I am that Eugenpaul doing vector layer generalization. Happy to be accepted, but it is also quite a responsibility, so I am feeling a very special mix of emotions right now. You may remember my proposal, but the work plan has been changed a bit, so I will briefly tell you what I have decided to do after several conversations with my mentor, Alexander Bruy. 1. My first aim now is to implement generalization for a collection of objects keeping their topological relations. Current implementation handles only one feature and avoids new intersections as a result of generalization. I'll take its base algorithm, the Douglas-Peucker, and add tracking of connected edges of the neighboring objects. 2. Then I will implement the on-the-fly generalization to speed up rendering. According to some tests done by Alexander [0], a simple distance threshold routine followed by the Douglas-Peucker algorithm shows significant reduction of the rendering time, especially with complex style lines. 3. Then I will look into the render cache realization. It is the right way of speeding up rendering, maybe there is a way to improve it. 4. At last, if I will have enough time, I'll try to adapt existing feature cache patch to the last QGIS version. Everything is planned to be supported by unit tests. All the progress will be described in the blog [1]. If you have any ideas on how to do these things better, please let me know. [0] https://picasaweb.google.com/lh/photo/avPtza_JMMdA5bkcOAr61tBgozyHltVoaaGmEBdHNL4 - shows dependence of rendering time on the number of lines and their style, "+gen" shows rendering time with on-the-fly simplification [1] http://blogs.gis-lab.info/ugnpaul/ Thank you! ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Displaying help for Python plugins
Hi Alexander, On Sun, May 13, 2012 at 3:03 AM, Alexander Bruy wrote: > Hi all, > > regarding to PyQGIS CookBook [0] plugin documentation can > be written as HTML files and to open help developer should > use method showPluginHelp() from qgis.utils module. > > In same time showPluginHelp() used deprecated method openURL() > from QgsInterface class [1]. And as I can see there are no alternatives > for this method. So what is best solution for displaying Python plugin > help in long-term period? Use showPluginHelp() as suggested in > cookbook or implement own method directly in plugins? > > [0] http://www.qgis.org/pyqgis-cookbook/plugins.html#documentation > [1] > http://qgis.org/api/classQgisInterface.html#374a28be05fac25b26f271f7ff19cd6d > You can use QDesktopServices [0] in lieu of QGIS openURL(), but I think you probably know this already: QtGui.QDesktopServices.openUrl(QUrl(some_url)) As part of my Plugin Editor tools, I have designed a lightweight web browser for displaying HTML help. It allows you to load pre-defined bookmarks, and has several useful tools for viewing help and tutorials from within plugins, but does not support several 'normal' browser features, like downloads. It is the first PyQGIS shared widget in the sister plugin to Plugin Editor, called Plugin Library. The idea behind the Library is to offer, via a PyQt GUI, a method to demo and browse available shared widgets, modules and snippets. Once the Library is installed, it acts like a PyQGIS virtual Python environment, from which other developers can use to import its different components into their plugins. It is an attempt to share code amongst Python plugin developers (without bothering the C++ coders to include into the GUI core), speed the development of plugins, and offer users similar GUIs across plugins (like a help browser). I'm not done with the Library plugin, but I am pretty much done with the first version of Help Browser (except for its help :^). Please download it and try it out, if you like [1]. Right now, it is just a package, but will later be a sub-package of the Library, accessible with: from plugin_library.widgets.help_browser.help_browser \ import HelpBrowser I have only tested it on Mac (10.7 and 10.6.8). Currently, on Mac with QGIS 1.8, any access to external web sites crashes QGIS. Works locally, though. [0] http://qt-project.org/doc/qt-4.8/qdesktopservices.html [1] http://dl.dropbox.com/u/4058089/qgis/help_browser.zip Regards, Larry Shaffer Dakota Cartography Black Hills, South Dakota ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] How to iterate over the vertices of a geometry from python
Sure. You can use: for v in geom.asPolyline(): print v.x(), v.y() asPolyline returns QVector which is just a List of QgsPoints in Python. Access like normal - Nathan On Sun, May 13, 2012 at 9:48 PM, Ricardo Filipe Soares Garcia da wrote: > Hi list > > I'm trying to translate and rotate a geometry using python, in order > to create parallel lines. > > For the translation I could use QgsGeometry's translate() method, but > for the rotation I haven't found a ready-made solution. So my current > strategy is to individually rotate each vertex, according to a > specified angle and length. For this i'd like to iterate over the > geometry's vertices. > > The problem seems to be that the api methods that return vertex > coordinates (vertexAt(), adjacentVertices, ...) always return a value > even if the specified vertex index is wrong. For example, if I use a > geometry with 5 vertices and call: > > geometry.vertexAt(100) > > -> (0,0) > > I cannot know if there is a vertex placed at the (0, 0) coordinates or > if there is no vertex at all. > Is there some way to iterate over a geometry's vertices? Or maybe get > an exception when asking for an invalid one? > > Thanks > > > -- > ___ ___ __ > Ricardo Garcia Silva > ___ > 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
[Qgis-developer] How to iterate over the vertices of a geometry from python
Hi list I'm trying to translate and rotate a geometry using python, in order to create parallel lines. For the translation I could use QgsGeometry's translate() method, but for the rotation I haven't found a ready-made solution. So my current strategy is to individually rotate each vertex, according to a specified angle and length. For this i'd like to iterate over the geometry's vertices. The problem seems to be that the api methods that return vertex coordinates (vertexAt(), adjacentVertices, ...) always return a value even if the specified vertex index is wrong. For example, if I use a geometry with 5 vertices and call: geometry.vertexAt(100) -> (0,0) I cannot know if there is a vertex placed at the (0, 0) coordinates or if there is no vertex at all. Is there some way to iterate over a geometry's vertices? Or maybe get an exception when asking for an invalid one? Thanks -- ___ ___ __ Ricardo Garcia Silva ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] how to create a new geometry from an existing one with python
Thanks I got it working now! I now have a different doubt, regarding geometry vertex iteration (sending another e-mail with it). On Sun, May 13, 2012 at 9:24 AM, Martin Dobias wrote: > Hi Ricardo > > On Sun, May 13, 2012 at 1:39 AM, Ricardo Filipe Soares Garcia da > wrote: >> [...] >> >> # python code >> >> line_geometry = >> qgis.utils.iface.mapCanvas().currentLayer().selectedFeatures()[-1].geometry() >> >> # approach 1 >> new_geometry = QgsGeometry(line_geometry) > > This approach is correct (and other seems to be fine, too). The > problem is elsewhere: you are being bitten by this bug: > http://hub.qgis.org/issues/777 > > Basically the problem is that the feature containing the line_geometry > gets deleted when the first line is executed. So your line_geometry > contains an invalid pointer leading to these strange errors. To > overcome this, store the list of features and then access it without > problems... > > Regards > Martin -- ___ ___ __ Ricardo Garcia Silva ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
[Qgis-developer] Displaying help for Python plugins
Hi all, regarding to PyQGIS CookBook [0] plugin documentation can be written as HTML files and to open help developer should use method showPluginHelp() from qgis.utils module. In same time showPluginHelp() used deprecated method openURL() from QgsInterface class [1]. And as I can see there are no alternatives for this method. So what is best solution for displaying Python plugin help in long-term period? Use showPluginHelp() as suggested in cookbook or implement own method directly in plugins? [0] http://www.qgis.org/pyqgis-cookbook/plugins.html#documentation [1] http://qgis.org/api/classQgisInterface.html#374a28be05fac25b26f271f7ff19cd6d Thanks -- Alexander Bruy ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] how to create a new geometry from an existing one with python
Hi Ricardo On Sun, May 13, 2012 at 1:39 AM, Ricardo Filipe Soares Garcia da wrote: > [...] > > # python code > > line_geometry = > qgis.utils.iface.mapCanvas().currentLayer().selectedFeatures()[-1].geometry() > > # approach 1 > new_geometry = QgsGeometry(line_geometry) This approach is correct (and other seems to be fine, too). The problem is elsewhere: you are being bitten by this bug: http://hub.qgis.org/issues/777 Basically the problem is that the feature containing the line_geometry gets deleted when the first line is executed. So your line_geometry contains an invalid pointer leading to these strange errors. To overcome this, store the list of features and then access it without problems... Regards Martin ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
Re: [Qgis-developer] Fwd: Threads in sextante
Hi Etienne, 2012/5/12 Etienne Tourigny : > I stand corrected then - I guess I was confusing it with ftools, which > is blocking and does not spawn a process. > Any way ftools could be adapted to use the same approach as gdaltools? most fTools functions already implemented as threaded, but there are some minor issues. I work on improving processes handing in fTools, and several tools already don't block main QGIS window, has non-modal dialogs and allows to cancel running process. Also I think about rewritting fTools in C++ and integrating its algorithms into QGIS analysis library. This makes tools a bit faster and will allow to use algorithms in plugins -- Alexander Bruy ___ Qgis-developer mailing list Qgis-developer@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-developer
