<br><br><div class="gmail_quote"><div dir="ltr">A dom, 6/03/2016, 21:39, Roy Marsh <<a href="mailto:roymarsh11@gmail.com">roymarsh11@gmail.com</a>> escreveu:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hi Alexandre</div><div>The data is UTM34S, coordinates about [20, -34], which is for the training exercise data (S Africa) - the layers created are where they should be</div></div></blockquote></div><div><br></div><div>Those values, if from south Africa, can't be UTM. UTM are in metres, and we should expect much higher values. Those are still in degrees.</div><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I converted the shp file using Properties 'Set Layer CRS', from default 'WGS 84' to 'EPSG 32734 / WGS 84 / UTM 34S'</div></div></blockquote></div><div><br></div><div>The explanation is here. Setting the layer CRS don't change it's coordinates values, it only tells QGIS to consider the values to be in that new CRS.</div><div><br></div><div>To convert the shapefile to a new CRS you need to right-click the layer and choose save as... And then choose the new CRS.</div><div><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>The data type of the target field is Double, with 5 decimal places</div><div>But then selecting the function $area just creates zero values</div></div></blockquote></div><div><br></div><div>Because saying QGIS the values were in meters you got sub-meter size features.</div><div><br></div><div>Good luck,</div><div><br></div><div>Alexandre Neto</div><div><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div> </div><div>I can't think of anything else to try and would be grateful for suggestions.</div></div><div dir="ltr"><div>Roy</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-03-05 23:18 GMT+00:00 Alexandre Neto <span dir="ltr"><<a href="mailto:senhor.neto@gmail.com" target="_blank">senhor.neto@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><p dir="ltr">Hi Roy,</p>
<p dir="ltr">Are you sure your data is UTM 34 S? How did you convert the data to that crs? What are the approximated coordinates values of your data<br>
?</p>
<br><div class="gmail_quote"><div><div><div dir="ltr">A sáb, 5/03/2016, 20:01, Roy Marsh <<a href="mailto:roymarsh11@gmail.com" target="_blank">roymarsh11@gmail.com</a>> escreveu:<br></div></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid"><div><div><div dir="ltr"><div>Hi</div><div>As a relative newcomer I have been working through the QGIS 2.14 training manual. Section 4.3.3 explains how to add calculated values using the Field Calculator. </div><div>But when I do this ..(the examples are from 2.8 but the same procedure seems to apply to 2.14).. the value stays as 0. It does this whatever parameters I try. It does this for both 'new field' and 'update field.' It does this even if layers are reprojected to UTM 34S (so as to show area in metres, not degrees). </div><div>Is this a bug?</div><div>Thanks</div><div>Roy</div><div><br></div><div><br></div><div><br></div></div></div></div>
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</blockquote></div><div dir="ltr">-- <br></div><div dir="ltr"><div>Alexandre Neto</div><div>---------------------</div><div>@AlexNetoGeo</div><div><a href="http://sigsemgrilhetas.wordpress.com">http://sigsemgrilhetas.wordpress.com</a></div><a href="http://gisunchained.wordpress.com">http://gisunchained.wordpress.com</a><br></div>