[Qgis-developer] Measure tool persistence.

Mon Oct 20 15:22:42 PDT 2014

Hello G. Garibaldi,

Like you,  I'm not a core programmer and therefore I depend on this fellows
goodwill, time and skills to make qgis a better tool for me to use.

With this in mind,  I have to say that you probably would have more success
if, instead of demanding for changes to meet your needs, you kindly asked
for help in the developers or users mailing lists. I bet that there would
be a few people giving suggestions to solve the problem,  without asking
anything in return. This has been working very well for me.

Also, it looks like your work depends on qgis. Not less than qgis depends
on you. So take some time asking yourself what could you do for qgis. If
some new tools are crucial for your work, please consider sponsoring it's
development (Developers also need to put food in their tables).

Now to your problem.

Since you need persistent measure tools, I would suggest you the following
workflow:

- Install "memory layer" and "memory layer saver" plugins (I think the
first one will became core in qgis 2.6);

- Create a new memory layer with lines geometries;

- Label your memory layer using $length in the expression;

- Whenever you need to measure something and keep it for further use, all
you need to do is draw a line in you memory layer instead;

Note 1: This can also be done with areas using a polygons memory layer;

Note 2: You can style the lines to create fancy measuring representations,
for instance by adding some arrows at the end and beginning  of the lines.

Hope this helps,

Alexandre Neto
Em 20/10/2014 20:29, "G. Garibaldi" <digitalmaps at cox.net> escreveu:

> Ah, this is useful. Let me mess around with this.
>
> Somebody has been busy since I last checked two years ago.
>
> On 10/20/2014 10:07 AM, Matthias Kuhn wrote:
>
>> Hi,
>>
>> It is very likely that better CAD functionality will hit QGIS soon. An
>> approach based on the CadInput plugin [1] is being discussed [2] and
>> parted to core [3]. Maybe this does already provide a lot of what you
>> need?
>>
>> Best regards,
>> Matthias
>>
>> [1] http://vimeo.com/85052231
>> [2]
>> https://github.com/3nids/QGIS-Enhancement-Proposals/blob/
>> cadtools/QEP-CAD-tools.rst
>> [3] https://github.com/qgis/QGIS/pull/1624
>>
>> On 20.10.2014 16:56, G. Garibaldi wrote:
>>
>>> Bug report #9703
>>>
>>> The line thickness is good. The endpoints could be improved.
>>> Crossmarks would be better than dots. If dot endpoints are easiest to
>>> program, then put a smaller white dot in the middle of the larger red
>>> dot. This will help measurement accuracy. The most desirable quality
>>> of the tool would be for the markers remain on screen until cleared by
>>> the user. This includes remaining on screen while other commands are
>>> selected and new data entered. This onscreen persistence should also
>>> be applied to the angle measure tool.
>>>
>>> With robust CAD tools this would not be an issue because the operator
>>> can quickly draw temporary measure lines on screen and erase them at
>>> his leisure. With QGIS the CAD tool functionality is clumsy and
>>> inefficient. Data point creation with other systems is fast and well
>>> developed. Most CAD systems allow inputting a data point, then drawing
>>> the next point using a relative angle and distance at the keyboard or
>>> visually with onscreen angle and distance display controlled by snap
>>> settings. Perhaps what I'm really asking for is better CAD tool
>>> functionality.
>>>
>>> I have many *thousands* of points to calculate and enter by hand.
>>> Months worth of work. If I were a programmer perhaps this would not be
>>> necessary. Unfortunately I don't think I have the time to spend a
>>> month or two getting up to speed programming in the QGIS environment,
>>> not that I would not like to. I just spent 7 months learning a foreign
>>> language to translate documents for my project. When the functionality
>>> of the measure tool changed after QGIS 2.1(1.8, 2.1 something like
>>> that), and the measure tool lost its persistence I despaired.
>>>
>>> I am pressing for this functionality because I need to finish my
>>> project and put food on the table.
>>>
>>> Anyway, this is my project, analyzing ships navigation data:
>>>
>>> https://www.youtube.com/watch?v=xCWZzqHc8ow
>>>
>>> In this project QGIS is merely a tool to develop a better
>>> understanding of historical events. What will really be significant is
>>> when QGIS goes 3D and I am able to visualize aircraft and ships data
>>> simultaneously in an animation using the animation plug-in.
>>>
>>> On 10/19/2014 4:48 PM, Tim Sutton wrote:
>>>
>>>> Hi
>>>>
>>>> On Sun, Oct 19, 2014 at 9:51 PM, G. Garibaldi <digitalmaps at cox.net
>>>> <mailto:digitalmaps at cox.net>> wrote:
>>>>
>>>>      The measure tool onscreen markers are not persistent and are
>>>>      therefore not useful. Why have tools that have no useful
>>>>      function? I've complained about this before, filed a ticket and
>>>>      was argued down by a developer.
>>>>
>>>>      It is frustrating to try to contribute to a project when nobody
>>>>      wants to cooperate.
>>>>
>>>>
>>>>
>>>> I don't think it is fair to characterise QGIS as a project where
>>>> nobody wants to cooperate. People are busy, may have differing
>>>> opinions to you, may not have noticed your ticket etc. We are a
>>>> community of people trying our best to cooperate and sometimes we
>>>> fail, but it certainly isn't through a lack of desire to cooperate.
>>>> My advice is keep trying (in a friendly way) to get your request
>>>> noticed, and if others don't always agree with your ideas, don't take
>>>> it personally.
>>>>
>>>> Regards
>>>>
>>>> Tim
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>      _______________________________________________
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>>>>      Qgis-developer at lists.osgeo.org
>>>>      <mailto:Qgis-developer at lists.osgeo.org>
>>>>      http://lists.osgeo.org/mailman/listinfo/qgis-developer
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> ------------------------------------------------------------
>>>> ------------------------------
>>>> Tim Sutton
>>>> Visit http://kartoza.com <http://kartoza.com/> to find out about open
>>>> source:
>>>>   * Desktop GIS programming services
>>>>   * Geospatial web development
>>>> * GIS Training
>>>> * Consulting Services
>>>> Skype: timlinux Irc: timlinux on #qgis at freenode.net
>>>> <http://freenode.net/>
>>>> Tim is a member of the QGIS Project Steering Committee
>>>> ------------------------------------------------------------
>>>> -------------------------------
>>>> Kartoza is a merger between Linfiniti and Afrispatial
>>>>
>>>
>>>
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>>
>>
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