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I'm using QGIS 2.2.0. I add a vector to a vector layer and save the file. After I reopen the .qgs file, the new vector is not shown.

(1) Click 'Toggle Editing'

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(2) Click 'Add Feature' and draw a polyline.

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(3) Click 'Save Layer Edits'

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(4) Click 'Save'

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What type of file is my_line? –  Michael Miles-Stimson Jun 16 at 0:46
It is a vector layer created using layer = QgsVectorLayer('LineString', 'my line' , 'memory') and QgsMapLayerRegistry.instance().addMapLayers([layer]) –  wannik Jun 16 at 1:04
An in-memory layer is not persisted. You need to save it as a shapefile or other file system type. They are intended only as a temporary storage for processing etc. –  Michael Miles-Stimson Jun 16 at 1:12
@MichaelMiles-Stimson Thank you very much for the info. I'm now able to save the vector. –  wannik Jun 16 at 1:34
You're welcome. I'll turn that into an answer in case anyone else encounters this problem. –  Michael Miles-Stimson Jun 16 at 1:37

1 Answer 1

up vote 7 down vote accepted

In memory layers are temporary, they don't get saved when you call save edits. They are only intended to be temporary and should be saved as a file system type (like shapefile) if you intend to keep their edits.

You should probably call QgsVectorLayer::setCoordinateSystem() on the layer before editing and definitely before saving. All spatial data should have a coordinate system, even if you make it the same as the canvas.

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