[OSGeo Africa] FOSS4G 2018: The Geospatial Event of the Year !

John Bailey john at blrland.co.za
Mon Jun 4 03:03:18 PDT 2018

Hi Zoltan

Thanks for this info.

I do have the old and new numbers in a spreadsheet format and will try that. Tim has kindly also provided a way of solving my problem.

For the duplication of the plot numbers I will delete all the duplicates as I notice on the attribute window that this is a problem.

I am no expert in QGIS so value your advice.

Thanks again.






From: Africa <africa-bounces at lists.osgeo.org> On Behalf Of Zoltan
Sent: 03 June 2018 06:36 PM
To: africa at lists.osgeo.org
Subject: Re: [OSGeo Africa] FOSS4G 2018: The Geospatial Event of the Year !


Hi John
You have not stated in what format you "have been issued with new plot numbers" - knowing this would help develop a strategy.
Judging by your QGIS Attribute manipulation question below, I'm guessing you might be more comfortable manipulating spreadsheets.
So, if as a sorted list (but note problem below), then this can be more of a spreadsheet problem than a GIS problem.

Export the attribute table as a spreadsheet (If in QGIS you now have it as a shape file, the dbf file can already be opened as a spreadsheet - but make a copy of it first :-)  )
Sort the spreadsheet according to the old plot numbers and patch in the new plot numbers either "on top" or inserted as a new column.
There are then a number of ways you can attach your new numbers to your QGIS map, and label accordingly.

BUT (this is the problem)

After numerically sorting the old numbers, the duplicates will be together.
How will you know which of the duplicates (they will be spatially different) gets which of the new numbers?

So, reality is, if you want more useful help, let us know in what format the 'new' numbers were issued to you.


On 2018/06/03 14:45, John Bailey wrote:




I have a residential layout in CAD format which I have exported to QGIS via a DXF copy of the plan.

The plan shows the boundaries of the plots and the plot numbers within each plot.

The plot numbers have been allocated by the Surveyor-General and have unfortuntely been duplicated. 

I have been issued with new plot numbers and want to introduce these onto the plan. There are about 2100 plot numbers.

The attribute table in QGIS lists the plot numbers.

How can I introduce a new field in the attribute table for the new plot numbers to enable these numbers to be shown on the layout plan.

Alternatively once the old numbers are in numerical order in the attribute table, how can I replace the old numbers in the plot number field with the new numbers?

>From here I will export the DXF from QGIS to CAD and update the layout plan.

Any asiistance will be much appreciated.

Kind regards

John Bailey




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Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services
P.O. Box 7, Muizenberg 7950, South Africa.
Mobile: +27-83-6004028
Fax:    +27-86-6115323     www.geograph.co.za <http://www.geograph.co.za> 
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