[Qgis-developer] QGIS inconsistency

[Steven Horner]

Hello,

I have been doing a project to calculate mountain viewsheds, basically
where a mountain summits can be seen from.

I have calculated the viewsheds and polygonized to Vector. So far so good,
but then I wanted to show which mountains could be seen from the summit of
other mountains I appear to have 2 problems.

1. I ran a spacial query to show how many mountains (Munros) are Within my
polgonized viewshed. This returns the Munros. Unfortunately I get a
different number in QGIS 1.8 to QGIS 2.0.1, I don't know which is true

2. I had saved my Viewshed originally as a shapefile with a CRS of 27700
(British National Grid), I saved a version as GeoJSON with CRS of 4326. If
I run the same spacial query on this file I get a different number of
Munros again.

So I now have 4 different figures from what I would have expected to be
identical.

Is data lost when a shapefile is saved as a GeoJSON file in a different CRS?
and which should I beleive 1.8 or 2.0.1 or neither?

If anyone wants to test this you can download the files here:
Viewshed Shapefile<https://dl.dropboxusercontent.com/u/2657852/AmBodach_shp.zip>-
CRS of 27700
Viewshed GeoJSON<https://dl.dropboxusercontent.com/u/2657852/AmBodach_geojson.zip>-
Converted fromthe above but with CRS of 4326
Munros Shapefile <https://dl.dropboxusercontent.com/u/2657852/Munros.zip> -
CRS of 27700

Wish I had realised there was something wrong before I had calculated 200
of these.

Thanks,
Steven
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