[Qgis-user] Using the ##passfilename tag for R script in Processing Toolbox
Ned Horning
horning at amnh.org
Thu Feb 13 05:59:48 PST 2014
Thank you Victor. I updated to the experimental version of the
Processing Plugin and it is working as you explain. I like the new
editor too.
I think the tag name is ##passfilenames and not ##passfilename as it is
written in the user guide.
I noticed that ##passfilenames only effects input files. Is there a way
to specify an output file that is not output using writeRaster? The
reason I ask is that I sometimes need to process an image in blocks
using the Raster package WriteStart, writeValues, and writeStop
functions. It would be great if there was a tag that would allow me to
specify an output file that could be used in that instance and still
output the image in QGIS. I have a workaround but it would be great if
there was a more direct way to do it.
Thanks again for all your help.
Ned
On 02/11/2014 05:17 PM, Victor Olaya wrote:
> No, that's not the idea off ##passfilename, the idea is that, instead
> of getting an R variable that is already a vector/raster layer, you
> get a string with its filename, so you can use it in R as you like.
> This was mainly done to allow the user to open a raster layer using a
> different package, and not use a fixed one and provide the layer
> object directly. So, if you declare a variable "mylayer" as vector
> layer, Processing will ask the user to select a vector layer, but the
> "mylayer" variable will have the path to the selected file. If you do
> not use ##passfilename, Processing will add some extra code, so the
> variable will already point to a data object created based on that
> filename.
>
> You can update to the newer version using the plugin manager. You
> should enable the "show experimental plugins" option, and you will see
> a new version of Processing.
>
> To make feature requests, you can use the QGIS issue tracker.
>
> Thanks in advance!
>
>
> 2014-02-11 22:51 GMT+01:00 Ned Horning <horning at amnh.org
> <mailto:horning at amnh.org>>:
>
> Hi Victor -
>
> Yes, I am using the version of Processing that comes with QGIS 2.0.1.
>
> I played with it some more today and I don't get an error if I use
> ##passfilenames (I added an "s" at the end) but it still didn't
> seem to work. I'm assuming that using ##passfilename will simply
> declare the directory path and file name as a variable instead of
> actually opening the file. It's quite possible I don't understand
> the intended functionality.
>
> Can you let me know the best way to make comments or make feature
> requests related to the R scripting capability. I'm glad I finally
> got around to trying it out.
>
> All the best,
>
> Ned
>
>
> On 02/11/2014 04:41 PM, Victor Olaya wrote:
>> Hi Ned
>>
>> That looks like a bug when parsing the script code. I will check
>> to see what I can do.
>>
>> Are you using the latest version of Processing, or the one that
>> comes with QGIS 2.0.1?
>>
>>
>> 2014-02-10 23:03 GMT+01:00 Ned Horning <horning at amnh.org
>> <mailto:horning at amnh.org>>:
>>
>> Hi -
>>
>> I am trying to learn to write R scripts using the Processing
>> Toolbox. I have a random forest image classification script
>> that works in the processing toolkit but I'd like to modify
>> it to do more complex tasks. I think I need to use the
>> ##passfilename tag but every time I add that to a script I
>> get an error that I pasted below. I tried several different
>> scripts and every time I add the ##passfilename tag I get the
>> same error. Does the ##passfilename tag need other
>> parameters? If anyone knows what the problem might be or has
>> pointers about how I can find the problem please let me know?
>>
>> This R scripting capability has a lot of potential and I'd
>> like to write a guide on how to use it but I still have a lot
>> to learn myself.
>>
>> All the best,
>>
>> Ned
>>
>>
>> I'm running QGIS 2.0.1 on Ubuntu 12.04. This is the error
>> message:
>> --
>> An error has occured while executing Python code:
>>
>> Traceback (most recent call last):
>> File
>> "/usr/share/qgis/python/plugins/processing/r/EditRScriptDialog.py",
>> line 95, in runAlgorithm
>> alg = RAlgorithm(None, unicode(self.text.text()))
>> File
>> "/usr/share/qgis/python/plugins/processing/r/RAlgorithm.py",
>> line 71, in __init__
>> self.defineCharacteristicsFromScript()
>> File
>> "/usr/share/qgis/python/plugins/processing/r/RAlgorithm.py",
>> line 82, in defineCharacteristicsFromScript
>> self.parseDescription(iter(lines))
>> File
>> "/usr/share/qgis/python/plugins/processing/r/RAlgorithm.py",
>> line 108, in parseDescription
>> raise WrongScriptException("Could not load R script:" +
>> self.descriptionFile + ".\n Problem with line \"" + line + "\"")
>> TypeError: cannot concatenate 'str' and 'NoneType' objects
>>
>> Python version:
>> 2.7.3 (default, Sep 26 2013, 20:13:52)
>> [GCC 4.6.3]
>>
>>
>> QGIS version:
>> 2.0.1-Dufour Dufour, exported
>>
>> Python path: ['/usr/share/qgis/python/plugins/processing',
>> '/usr/share/qgis/python', '/home/nedhorning/.qgis2/python',
>> '/home/nedhorning/.qgis2/python/plugins',
>> '/usr/share/qgis/python/plugins', '/usr/lib/python2.7',
>> '/usr/lib/python2.7/plat-linux2',
>> '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old',
>> '/usr/lib/python2.7/lib-dynload',
>> '/usr/local/lib/python2.7/dist-packages',
>> '/usr/lib/python2.7/dist-packages',
>> '/usr/lib/python2.7/dist-packages/PIL',
>> '/usr/lib/python2.7/dist-packages/gst-0.10',
>> '/usr/lib/python2.7/dist-packages/gtk-2.0',
>> '/usr/lib/pymodules/python2.7',
>> '/usr/lib/python2.7/dist-packages/ubuntu-sso-client',
>> '/usr/lib/python2.7/dist-packages/ubuntuone-client',
>> '/usr/lib/python2.7/dist-packages/ubuntuone-installer',
>> '/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol', '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode',
>> '/usr/share/qgis/python/plugins/fTools/tools']
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