In[]:=
tab3=ToTabular[Map[{#}&,latlong],"Rows",<|"ColumnKeys"->{"latlong"}|>];​​​​latLongToUTM[latLong_]:=GeoGridPosition[GeoPosition[latLong],"UTMZone33South"]["GridXY"]​​​​TransformColumns[tab3,{"utm"->(latLongToUTM[#latlong]&)}]
Out[]=
Tabular
Row count: 1000
Column count: 2
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