[OSGeo Africa] How to load .ort DEM into QGIS

[Melissa Akoue Mve]

Hi Gavin and Walter,

Sorry for my late response.  I got caught in meetings and only managed to
try out your suggestions late on friday and this morning.

I tried both ways and they both work well. Walter's suggestion of
downloading the SRTM 30m DEMs is the faster method because I can download
the images as geotiffs and load them in directly without Grass or any other
manipulation.  However I have learnt a lot from trying Gavin's method too.

Thank you both for your invaluable assistance.  This discussion group is
very valuable tool.

Regards,
Melissa

2015-04-24 13:50 GMT+02:00 Jean Paul Ngalams <jpngalams at gmail.com>:

> Thank you Gavin for your answer to Melissa's question; I had the same
> preoccupation.
>
> On Fri, Apr 24, 2015 at 12:17 PM, Gavin Fleming <gavin at kartoza.com> wrote:
>
>>  Hi Melissa
>>
>> I've just done one of the NGI ort files (2631AA07.ort) in GRASS (result
>> below). Pretty much everything you need is at
>> http://grasswiki.osgeo.org/wiki/Import_XYZ. Note there are multiple
>> spaces so you'll have to use the trick on that page to collapse multiple
>> spaces to single spaces. Also note the coordinates are south facing TM so
>> you'll have to do one zone at a time then project them together, or project
>> all to UTM or Albers first.
>>
>>
>>
>> You should be able to import directly in QGIS (which uses GDAL) after
>> re-ordering the data as per http://www.gdal.org/frmt_xyz.html. However
>> on this one I tried, GDAL thinks the number of lines doesn't match the size
>> of the grid it has calculated so it fails., so I just switched to GRASS.
>>
>> Good luck and let us know when you've done it (and how you did it).
>>
>> Gavin
>>
>>
>> On 24/04/2015 11:09, Melissa Akoue Mve wrote:
>>
>> Hi All,
>>
>> I need to do a slope analysis of the whole Western Cape area.   I had
>> planned to do this with the raster tool set in QGIS but after getting the
>> DEM's from the NGI I discovered their DEMs are in a .ort format which is
>> not a standard GDal format.
>>
>> I was informed that the only way to load this .ort into QGIS is by
>> converting it to a CSV and then loading the CSV file into QGIS, and then
>> converting it to raster when in DEM.   I have tried this but it is
>> laborious and will take too long because there are more than 50 NGI DEMs
>> that make up the Western Cape area.
>>
>> Does anyone know of a simpler way to load the .ort file.   I have
>> searched for ways to convert the .ort to a geotiff but I havent been
>> successful yet,
>>
>> Kind Regards,
>> Melissa Akoue Mve,
>>
>>
>>
>>
>>
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>>
>>
>> --
>>
>> ------------------------------------------------------------------------------------------
>>  Gavin Fleming Joint MD PrGISc [PGP1234]
>> Visit http://kartoza.com to find out about open source:
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>> * GIS Training
>> * Consulting Services
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>>
>> -------------------------------------------------------------------------------------------
>> Kartoza = Linfiniti ∪ Afrispatial
>>
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>
>
>
> --
> Jean Paul NGALAMULUME TSH.
> Contact:+243 9 97 53 47 59
>                ngalamjp at yahoo.fr
>                Skype:jp.ngalams
>
>
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