dhis2-devs team mailing list archive

[Knut Staring <knutst@xxxxxxxxx>]

Hello Zeferino and all - the issue of projection is likely to come up
in many settings, also when we convert to GML for import. It is
already described in 10.2.4 in the user manual, but let me elaborate a
bit:

On Tue, Jul 20, 2010 at 9:05 PM, zeferino saugene
<zeferino.saugene@xxxxxxxxx> wrote:
> Hi Knut,
>
> Hope you are doing fine.
> I am sending attached to this email two files containing spatial data of Malawi.
> I have converted this data to geojson but when i try to map this with
> the DHIS2 the map is not comming in the panel. I have used Long:
> 33.71073 and Lat: -13.25489.

The problem is that the original files have a different projection
from the one we use as standard in DHIS2, namely lat/lon. Therefore,
you have reproject. You must first determine the source projection,
which for Malawi will often be UTM 36S, as you can see here:
http://upload.wikimedia.org/wikipedia/commons/e/ed/Utm-zones.jpg

Alternatively, UTM 36S corresponds to EPSG 2736, as you can see from here:
http://spatialreference.org/ref/epsg/?search=36s&srtext=Search

We want the data in EPSG 4326, which is Lat/Lon.

This means we can use ogr2ogr (part of FWTools) to reproject as you
convert to geojson, in two different ways. Either with EPSG:

ogr2ogr s_srs EPSG:2736 a_srs EPSG:4326 -f "GeoJSON" outputfile.json
inputfile.shp

Or with UTM -  I am not sure of the syntax here, but it should be
something like this:
ogr2ogr -s_srs "+proj=utm +zone=36 +ellps=GRS80 +units=m +no_defs
no_defs <>" a_srs EPSG:4326 -f "GeoJSON" outputfile.json inputfile.shp

It should also be possible to reproject your already generated geojson
files, I'll give this a try and send you the result.

Knut

> Unfortunately the internet is very low i cant test the generated geojson file.
>
> Can you please check what is wrong with this spatial data.
>
> Regards,
>
> Zeferino
>



-- 
Cheers,
Knut Staring