[QGIS-Developer] newbie questions re: exe or dll to batch-process shapefiles

[Willson de Veas]

Hi, I'm a newbie to QGIS, with several years of experience with other GIS
software, particularly ESRI MapObjects and Atlas GIS.

I've also been a software developer (mainly Windows desktop applications)
for many years. I'm concurrently learning Python in order to interact with
the QGIS API.

My latest direction from my employer is to create software that
batch-processes spatial data (for now, ESRI shapefiles) non-interactively,
with "Python and QGIS".

(I don't actually know yet whether I should be looking at QGIS's API for
purely non-interactive processing, or at GDAL/OGR, as suggested by someone
on Twitter.)

I'd like to ask some questions in order to guide my learning. I ask for
your pardon in advance as some of my terminology may still be ESRI-centric.

I have been tasked with creating a routine that does the following:

    1) reads in as parameters (i) the filename of one shapefile,
representing an overlay layer; (ii) one or more filenames of shapefiles,
representing target layers; and (iii) an output folder name;
    2) loads the overlay and target layers, reprojecting each as necessary
into a common projection (we're expecting to convert Albers
projection-NAD1983 to Transverse_Mercator-NAD_1927_UTM_Zone_10N);
    3) for each target layer, find all features that touch any feature in
the overlay layer, and export all of these to a new shapefile in the output
folder.
    4) This would be called by another Windows desktop application.

The ideal solution that my employer and I are seeking would be a Windows
executable or DLL, with minimal additional installation overhead. I am
aware of py2exe and cx_Freeze, and I've seen the "Python on Windows FAQ".

Is this a feasible project? Is it a wise project?

Does accessing the QGIS API launch a separate window / do I have to launch
a new and visible process in order to access QGIS via API calls?

Should I be looking at GDAL/OGR for non-interactive background work instead?

What other considerations should I be aware of?

Thanks for your time and attention.

Regards,
Willson de Veas
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20171228/c142df87/attachment.html>