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I have a situation where planning is done on a "base map" consisting of rivers, contours, roads etc. There is a need to create a "overlay(s)" over the "base map" consisting of drawings, that could be point(s), line(s) or polygon(s) on one overlay.

Is it possible to create point, line and polygon features on one QGis layer/overlay I have looked at the vector overlay with a memory data provider but it looked like you can only create a instance of the memory data provider for one type of feature only?

I would appreciate any help, thank you.

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3 Answers 3

up vote 2 down vote accepted

You can use groups in order to turn a set of layers on and off together. Just CTRL+click the layers you want in a group, right click one of them and select "Group". The layers will remain separate entities but you can turn them all on or off at once rather than manually finding the layers you need for a given scenario.

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It's not possible to mix geometry types in layers. You will need to add separate layers.

Also, I'd recommend splitting the layers by topic, e.g. one layer with buildings, one with general zoning info. Don't just throw everything into one layer, otherwise you will have a mess to clean up later. Also styling is going to be easier with more layers.

As @Willy commented, you could have different projects for different scenarios. Look into the "embed layers and groups" functionality in layers menu to keep the background layers synced between scenario projects.

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Its a pity, because we would like to use it for command and control, where plans are drawn over "base maps", routes, assembly areas, drop zones, etc. is planned on one overlay, a contingency plan can be on another overlay, a perceived enemy plan another. Having one plan on different overlays is going to confuse the user. –  Theuns Heydenrych Oct 4 '12 at 6:49
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Maybe you need to consider different projects as different scenarios. Various projects can use some common layers and have their own specific layers. –  Willy Oct 4 '12 at 8:36
    
do the terms of use for QGIS include war? (sorry, I'll sign off for the night now....) –  Willy Oct 4 '12 at 11:48
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Perhaps it might be more convenient to export your "base map" to a high-resolution image and then georeference this? Then you could plot your overlays on the image. N.

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