[Qgis-user] FH 3 questions (million points, metadata, projection bug); thanks

[Richard McDonnell]

Hi,
My suggestion would be to use PostgreSQL and PostGIS to store the points. As for the reprojections, just use additional geometry Columns for this, Create x and y columns (your_geom_coll_1 or 2 below) and use

SELECT AddGeometryColumn (your_schema,your_database, new_geom_coll_name, EPSG:Your_CRS,'POINT',2);
UPDATE your_table SET geom_coll_name=st_setsrid(st_makepoint(your_geom_col_1,your_geom_coll_2),your_CRS);
Also, run indexing of your geometry columns.

CREATE INDEX your_index_name ON your_table  USING GIST (your_geometry_column);

You can use Queries/filters within QGIS to help carry out your edits, even with PostGIS 6 million points is going to be a lot vector data to render, so keep rendering to a minimum.
Just a suggestion, it would be how I would deal with this.
Regards,

Richard McDonnell

--

Richard McDonnell
GIS Specialist | FRM Data Management
MSc Geographic Information Systems

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From: Qgis-user <qgis-user-bounces at lists.osgeo.org> On Behalf Of Falk Huettmann
Sent: 07 September 2019 09:24
To: qgis-user <qgis-user at lists.osgeo.org>
Subject: [Qgis-user] FH 3 questions (million points, metadata, projection bug); thanks

Dear Colleagues,
a few questions if I may:

-I am doing 3 million points, overlays, reprojections and table edits,
 and an expensive GIS package failed on us 'esrliy' (I like this word, in case it actually is one).
 So we ran it in QGIS and the entire project saved; hooray! THANKS!!!!
 Anyways, how about we want to run 6 million points in QGIS ?
 How to do it best ? Any advise ?

-we find a consistent bug in QGIS when using Mercator projection and with a 180 degree meridian.
 Chukotka peninsula data do not show up; perhaps you know of a cure ?
 I am happy to send you the shapefiles and grids to look at.

-I love MetaEdit; well, except, I cannot find it in the PlugIns and the
 website seems to be not supported anymore.
 http://gis-lab.info/qa/metatools-eng.html
 Any hints for ISO compliant XML metadata  editor with QGIS ? QGIS needs it.

Thanks so much again; very best
   Falk Huettmann





On Mon, Aug 26, 2019 at 9:43 AM Falk Huettmann <fhuettmann at alaska.edu<mailto:fhuettmann at alaska.edu>> wrote:
Dear Kind Colleagues,

thanks, I have a similar question, but with an opposite aim:

We have two points,
and want to connect them,
but then, NOT with the most direct and shortest path.
Rather, with the most meaningful and considerate one.
Like,
length is not to be penalized but other factors, habitats available, amount of pixels
underneath etc.
Perhaps even showing different scenarios (aka, many paths lead to Rome...) ?
The path can consist of more than a line, an area connection let's say.

So in other words: the optimization is NOT done by short distance.

Would you have any ideas and suggestions on that ?

Thanks so much for any input
   Falk Huettmann






On Mon, Aug 26, 2019 at 2:07 AM Chintan Advani <chintanadvani at gmail.com<mailto:chintanadvani at gmail.com>> wrote:
Hi guys,

I have a shape file with set of points on a road network. I am trying to find the shortest distance among these points using the shortest path tool. I have tried using the distance matrix tool in QGIS but it gives eucledian distance between these points whereas I am looking the path distance (based on road network). Can someone please suggest some tool or technique that can help me solve this problem?

Thanks and Regards,
__________________________________________
Advani Chintan Sanjeev
        Research Scholar,
        Civil Engineering and Build Environment,
        Queensland University of Technology,
        Brisbane-4000, Australia.
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