[Qgis-user] Generate Text Labels for USA National Map?

[Jeshua Lacock]

> On Jul 5, 2017, at 2:32 AM, Bernhard Ströbl <bernhard.stroebl at jena.de> wrote:
> 
> - I assume you want to have QGIS create label texts for all your data in one go.

Hi Bernhard,

That would be ideal.

> If that is the case this is a misunderstanding of what labels are (in QGIS): QGIS creates (and places) the labels at run-time for the map extract currently on display. Labels thus are no features of their own (GIS only knows points/lines/polygons) but a way to display GIS features (like e.g. color, outline etc.)

I was afraid that might be the case. :’(

> - This means the labels are valid for this particular map extract in this particular scale. E.g. imagine a lake (= one polygon) that expands on two map extracts, it will be labeled in both => one feature, two labels

Understood. I was thinking of generating text at say 4 different scales.

> - Thus the label text is only within QGIS, export may be possible with dxf-export

Is it possible to script or automate setting the view extents and exporting?

> - IMHO it doesn't make sense to try to use the labels outside of QGIS; what is your intended final result? Which software are you planning to use for creating your final result?

Initially it will be a custom iOS app (with planned android and possibly desktop computer versions). I might offer printed hard copies too at some point.

> - There will be map extracts with "many" labels (city centres) and map extracts with "few" labels (boondocks).

Yes, that is why I was looking for something that already can deal with crowded text versus re-inventing the wheel.

> - QGIS can prevent overlapping labels; in placement you can assign a priority to the labels of this layer (so e.g. rivers are always labeled whereas streets only if not in conflict with rivers)

Nice.

> - The rule based labelling works _within_ a layer; a rule is a logical statement about the feature to be labeled. The logic can be based on the feature's attribute values or geometry (e.g. label only lakes larger than x)

So essentially, I would want all the text on one layer - so point text doesn’t overlap with say road or river text, correct?

> - points are vector features, too, so there is no real difference between labelling points, lines or polygons.

Great.

> - Be sure to have read the doc: http://docs.qgis.org/2.14/en/docs/user_manual/working_with_vector/vector_properties.html#labels-menu#

Thanks for the link and help!


Best,

Jeshua Lacock
Founder/Engineer
<3DTOPO.com>
GlassPrinted.com