dhis2-devs team mailing list archive

[Jason Pickering <jason.p.pickering@xxxxxxxxx>]

Hi Knut,

> It may be that we want to use DHIS as both a repository with full
> precision (though not ridiculously artifical ones like 15 decimal
> lat/lon) and have a faster way of renderin. But for a repo, I think
> something like PostGIS is in order. Or we could just store things as
> GML...

Well, this is really the issue. If DHIS is going to be a repository,
any self-respecting GIS geek would not use it if the application
clipped precision. Although a few meters is not significant in terms
of rendering a map, it may cause havoc on certain datasets,
particularly if there are topological relationships between different
layers. If a facility is related topologically to a road network, and
the point is shifted a few meters, this may result in disturbance of
the topology between these layers, rendering DHIS useless as a
repository. ogr2ogr is perfectly OK as long as we are not dealing with
these types of layers, but as soon as we start to think about
relationships to other layers, we need to be very careful about how
the data is preprocessed.


> We should be very conscient of not pushing the new, very simple
> solution too far, for more complex functionality we should rather
> employ Geoserver and PostGIS - and I still think this is the best
> solution for a national repository. Our new way of storing orgunit
> boundaries is a very small subset of such a full blown GIS solution,
> but has the advantage of being simple, lightweight and portable.

Agreed on both points, namely that the solution is lightweight and
aimed at thematic mapping but other solutions would be more
appropriate for use as a repository of GIS data.

Regards,
Jason



-- 
Jason P. Pickering
email: jason.p.pickering@xxxxxxxxx
tel:+17069260025