Opened 13 years ago
Closed 13 years ago
#3244 closed bug (invalid)
AddGeometry- faulty units and precision
| Reported by: | muscatelle | Owned by: | nobody |
|---|---|---|---|
| Priority: | major: does not work as expected | Milestone: | Version 1.7.0 |
| Component: | Build/Install | Version: | 1.5.0 |
| Keywords: | ADD Geometry units precision | Cc: | |
| Must Fix for Release: | No | Platform: | Debian |
| Platform Version: | Ubuntu 10.04 | Awaiting user input: | no |
Description
Using Tools>GeometryTools>Export/AddGeometryColumns, has some problems with units and precision.
Output seems to be in units of 100km eg
An area 69.38Ha (measured using the measurement tool) is output as 6.9e-05 Perimeter ~ 3.3Km (measured using the measurement tool) is output as .032753
This has the potential to cause errors and produce misleading information on subsequent calculations
Project units are m.
Sample files before and after Add Geometry are attached
Workaround is at: http://forum.qgis.org/viewtopic.php?f=2&t=7531#p15730
Attachments (1)
Change History (2)
by , 13 years ago
| Attachment: | saCensus2006_test.zip added |
|---|
comment:1 by , 13 years ago
| Resolution: | → invalid |
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| Status: | new → closed |
The attached shapefile is not in a projected coordinate system, so measuring area and perimeter does not really make sense. As mentioned in the forum thread linked to this ticket, you will need to reproject your data to a projected coordinate system that supports measuring areas. This tool does not use the project CRS, and for good reason: it outputs the area and perimeter as attributes of a layer, so while the project properties may vary from project to project, the layer itself does not.
I am going to close this as 'invalid'. If you feel that this should not be the case, please feel free to reopen the ticket.
Carson
Before and after AddGeometry operation