[Qgis-developer] QGIS Layer Search Plugin

Wed Jun 8 06:36:05 PDT 2016

With these discussions I want to make it clear what the LayerSearch plugin
use is intended for and what it is not.

What it is:

1. It provides the user the ability to search all layers and all fields
against a particular search string. It may be that the user already knows
the layer he is interested in, but that is not always the case. It is
possible that the user has a number of layers that contain similar data. I
really do intend for it to search multiple layers, but LayerSearch has the
ability to select a single layer and single column if desired.

2. It does not require any pre configuration other than the search feature
and whether you want an exact match, a match at the beginning of a data
field, or a match anywhere in the data.

3. The resulting matches display what layer and column the match was found
in and by clicking on the match QGIS will zoom to that feature.

4. While searching on a large data set you can click an explore the found
features even while it is still searching.

What it is not:

The fastest search engine in the world. It is not meant to be used to
search a reference data set like Quick Finder does. I would not want it to
do any pre indexing or pre configuration. That is not its purpose. I just
tried a geonames data set with 2.2 million records,  LayerSearch completed
the task in 45 seconds on my laptop. That is acceptable to me. In the mean
time I was able to look at the matches it was finding. Even though I say
this, I am interested in optimizing it to be as fast as possible, but I
don't what the user to have to index the data or do any pre configuration
first.

BTW when you talk about moving to "Processing" what are you talking about?
Are you talking about the Processing toolbox or something else? I am new to
the development side of QGIS.

All the best,

Calvin

On Wed, Jun 8, 2016 at 2:20 AM, Denis Rouzaud <denis.rouzaud at gmail.com>
wrote:

> Dear all,
>
> Indeed, the layer search offers something Quickfinder doesn't: searching
> on all layers without any configuration, and the use of operators.
> Although I think choosing an operator in a global search is not very
> required (why doing price < 1000 on all layers, there is a pretty good
> chance you know what layer you're looking for).
>
> From this, I think Michael's idea is pretty good.
> Make QuickFinder just a search bar in the application toolbar. Then you
> can register any search process to it, which would be a processing alg:
> might be OSM, FTS or Layer search.
>
> I would definitely be ok to do so for QuickFinder.
> But the question is when... It would take me a bit of time to reorganize
> the plugin, make FTS generation and search as processing algs (never done
> that before). I won't be able to achieve this before August.
>
> So...is this fair to ask someone to wait that long for a dev and then ask
> to modify its code to fit in? I have no answer, it's a real question.
>
>
> Best wishes,
> Denis
>
>
> PS: yes, QuickFinder FTS search handles multiple columns as it supports
> expressions (you can concatenate the columns).
>
>
>
>
>
>
>
> On 06/07/2016 03:27 PM, kimaidou wrote:
>
> Hi all,
>
> I think it is not really profitable to have multiple plugins. In my
> opinion, efforts must be made to merge plugins when possible. In this case,
> we have
>
> * Quick Finder : Full Text Search is used here, which allows fuzzy search,
> and is very efficient compared to scanning all features for a match. A
> drawback, you must fill in the "FTS vectors" for each layer you want to be
> able to search within. I think it is not so bad because the process is
> fast. I also think there is nothing preventing to add more than one field
> in the search ( it is possible with FTS in PostgreSQL, must also be the
> case with sqlite)
>
> * Layer search : Great to have a quick way to search among all the fields
> of all loaded layers, with no configuration. Drawback : I think this can be
> very slow for big datasets, and it is not "fuzzy", as regexp are used while
> iterating on each feature. Another drawback : for external vector sources
> like PostgreSQL, all features must been fetched !
>
> IMHO, the way to go could be
>
> * Add the FTS pregenerator of Quick Finder in Processing, as an alg
> available for anyone to use
> * Add the FTS search of Quick Finder as a Processing Alg
> * Add the "layer search" worker as an Alg in Processing
> * Have a combined plugin which let the user choose the search type : FTS
> with pregeneration, or direct search with features iteration. This will
> then run the corresponding alg
>
> Cheers,
> Michaël
>
> 2016-06-07 7:16 GMT+02:00 Jeremy Palmer <JPalmer at linz.govt.nz>:
>
>>
>> >
>> > I would personally prefer keeping it as a separate plugin, but what do
>> you
>> > think? Should it be integrated with another plugin?
>> >
>>
>> It seems like it has value over the other plugins. Another issue I’ve had
>> is searching all layer fields and pushing the query filter down the
>> provider (e.g PostGIS or WFS) to increase the performance and usability.
>> Using the approach of iterating through all features client side with a
>> large dataset can be a killer in terms of bandwidth, memory and time. Does
>> your new plugin do that? If so then it would be really useful :)
>>
>>
>>
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