[Qgis-developer] Tool to pick up linear referencing measure from mouse

[Radim Blazek]

On Mon, Nov 23, 2015 at 6:00 PM, Régis Haubourg
<regis.haubourg at eau-adour-garonne.fr> wrote:
> Hi,
> I'm having a classical use case here. Before starting a new plugin, and
> since it is a very common task in GIS, I would like to know if anyone has
> made something alike:
>
> - I have a postgis db with LINESTRINGM routes (watercourses already
> calibrated with measures).
>
> - I have a non geometric table registering events with start and end
> measures + identifier of my routes (watercours ID).
>
> - I create my event in the attribute table, with one ID and two manually
> typed measures, then a view cast it to spatial view using
> locate_beetween_measure function.
>
> I would like to create a form with two tools dedicated to "pick up" my route
> and the measure. i've done it in Arcview 3.2 once in the old past..
> What could be the current better and simpler approach in QGIS?

I think that now (>=2.8), when QGIS geometry supports M (measure), the
measure calculated for the nearest point on the identified line
could/should be added to derived attributes in standard identify
results.

> LRS plugin does not have that feature, and requires to recalibrate layers
> from scratch.

Similarly Locate, Create events and Calculate measures tools in the
LRS plugin should be extended  to support existing layers with
measure.

Radim

> Could we dream for the future of a new generic form widget with custom
> expressions to get attributes or geometric information from a layer (with
> snapping options )?
>
> Cheers
>
> Régis
>
>
>
> --
> View this message in context: http://osgeo-org.1560.x6.nabble.com/Tool-to-pick-up-linear-referencing-measure-from-mouse-tp5238110.html
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