[pdal] execute a pipeline from python

[Dan Lipsa]

On Wed, Jan 31, 2018 at 3:11 PM, Howard Butler <howard at hobu.co> wrote:

> When you .execute() a pipeline in Python, you get back the data in the
> pipeline.arrays variable. In a stream scenario, that behavior would be
> disrupted, or we would need to have it return an iterator or something.
>

I see.


>
> If you want to just execute a pipeline in stream mode without caring for
> the numpy arrays of the data, is the a reason to not simply use subprocess
> and invoke the shell?
>
I was just thinking about not going through the shell, but probably the
effect of that compared with the total time would be negligible.

Thanks again!




> Howard
>
>
>
>
> On Jan 31, 2018, at 1:54 PM, Dan Lipsa <dan.lipsa at kitware.com> wrote:
>
> Hi Howard,
> Thanks for your answer.
>
> I was thinking more along the lines of what the command line tool does:
> just set on option "stream" to the pipeline.
> Is this choosing a default chunk (buffer) size?
>
> For instance the following pipeline takes several point cloud "bricks"
> and generates the dsm for the whole surface covered.
>
>
> {
>   "pipeline": [
>     "a.bpf",
>     "b.bpf",
>     {
>       "resolution": 0.25,
>       "filename":"test.tif",
>       "output_type": "max",
>       "window_size": "20",
>       "bounds": "([740698.8745, 741144.3546], [4404897.242, 4405465.48])"
>     }
>   ]
> }
>
>
>
>
> On Wed, Jan 31, 2018 at 2:43 PM, Howard Butler <howard at hobu.co> wrote:
>
>>
>>
>> On 1/31/18 1:37 PM, Dan Lipsa wrote:
>> > Hi all,
>> > I can enable streaming in a pipeline using
>> >
>> > ./pdal pipeline --stream dsm.json
>> >
>> > Can I do the same thing in python?
>> > What is the option that I need to set?
>> >
>> > pipeline = pdal.Pipeline(json)
>> > pipeline.validate()  # check if our JSON and options were good
>> > count = pipeline.execute()
>> >
>>
>> Dan,
>>
>> No, that bit of Python API isn't done yet. There's a bit of a question
>> of what we should do there too? Presumably the API would have the user
>> set a chunk size and then return an iterator. The API to follow would be
>> the PipelineKernel.cpp implementation, but apply it to the Python/Cython
>> extension stuff.
>>
>> I'd be happy to merge a patch that did this.
>>
>> Howard
>>
>>
>> _______________________________________________
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>>
>
>
>
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