[FOSS-GPS] GPS issues for Ethiopia

[julio menezes]

Dear Andrea.


--- Em qui, 25/10/12, andrea antonello <andrea.antonello at gmail.com> escreveu:

> De: andrea antonello <andrea.antonello at gmail.com>
> Assunto: [FOSS-GPS] GPS issues for Ethiopia
> Para: foss-gps at lists.osgeo.org
> Data: Quinta-feira, 25 de Outubro de 2012, 9:19
> Hi I need some information about the
> above subject.
> 
> We are planning a educational project for water management
> networks in
> Ethiopia and we applied to get a precision GPS to do the
> surveys.

good luck, especially because of the project mission.

I have been using GPS for years for dams projects.
> 
> We just got hit by one very upset persons responsible for
> the project
> that told us that a professor of topography explained them
> that:
> "since in Africa there is not geoid, the GPS is useless"
> 

I have bee using GPS for years for damms projects. 
Sometimes we use egm2008 to get relative geoid undulation.
With the relative geoid undulation and geometric height difference we get relative orthometric difference. We can use it in small areas, unless there are some geoid anomaly. 

Perhaps it helps you as you have no spirit leveling network.
Take a look over EGM2008 for your area.
 

> Apart of the citation, which may rise some comments on its
> own, I was
> wondering if there is something I am not considering and
> should really
> know. We have used gps in Rwanda without problems for the
> same
> purposes and I am quite puzzled about what I am missing.
> 
> Any advice or link to documentation is very appreciated,


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