[Qgis-developer] Reading a new type of file natively in QGIS

Pedro Camargo veigacamargo at gmail.com
Fri Dec 12 16:14:24 PST 2014

Hi Alex,
                 This matrix is a transportation demand matrix, where the
indices represent the node of origin and the node of destination in the
network. They could be interpreted as vectors, I think, if you think in the
sense that both the origin and the destination do have coordinates, but
representing them as lines do not make any physical sense.

   Did my explanation help at all?



On Fri, Dec 12, 2014 at 2:46 PM, Alex Mandel <tech_dev at wildintellect.com>

> On 12/11/2014 08:21 PM, Pedro Camargo wrote:
> > Hi group,
> >                 During my discussions with people from the transportation
> > modeling world, some people pointed out a few features that would be nice
> > to have in order to use QGIS more intensively by our group.
> >
> >                 The most important issue, however, was the possibility of
> > open matrices in a very efficient way (reading matrices that are
> > 10.000x10.000 in dbf format means reading 10e8 lines, which takes a VERY
> > long time and defeats the purpose of using QGIS for some things.
> >
> >                 A very good alternative would be using an open source
> > format from the project "open model data"  (
> > https://sites.google.com/site/openmodeldata/) which is based on HDF5.
> >
> >                 I see that QGIS can already open raster data in HDF5
> > format, but in this case, the data would be a matrix with indices and
> all.
> >
> >                I regret to say that my programming skills, specially in
> > C/C++ are not nearly good enough to evaluate the effort that it would
> take
> > include such support and have, inside QGIS, a possibility of viewing such
> > matrices, which would allow people from the transportation world (and I
> am
> > the first volunteer) to develop the necessary plugins to manipulate the
> > matrices and generate the commonly used statistics.
> >
> >               Can anybody tell me what type of effort it would take and
> if
> > it is at all of interest of the QGIS community?
> >
> > Thanks a lot,
> >
> > Pedro
> This is more a question for GDAL/OGR I think.
> How do your matrix values relate to map objects? Is your matrix a vector
> or a raster?
> What do you want to do with the data inside QGIS?
> Thanks,
> Alex
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