Questions tagged [postgis]
PostGIS is an extension for the PostgreSQL object-relational database that adds support for geographic objects.
7,257
questions
0
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1answer
24 views
Does the projection of a PostGIS table affect the rendering speed in QGIS
I am interested to know whether changing the projection of a PostGIS table will affect the rending speed when viewing it in QGIS.
I have two layers coming from QGIS which are exactly the same and ...
1
vote
0answers
14 views
st_3dshortestline equivalent in Python 3
I have two geopandas Dataframes with 3D geometry. I could transform it in any other data type it could be more easy to use.
I would like to know if there is something similar to the st_3dshortestline ...
0
votes
0answers
22 views
PostGIS with GeoJSON: `geometry` v. `geography`
Does the GeoJSON spec imply or strongly suggest that PostGIS geometry type should be used over geography?
Looking at section 3.1.1 I am seeing that
In other words, every point on a line that ...
1
vote
0answers
25 views
Tenant isolation in SaaS product based on PostGIS - do the same concepts as PostgreSQL apply?
We're working on two different GIS apps and we're a bit torn around how to provide a level of tenant data isolation on our GIS systems.
System A would need to have strong tenant data isolation where ...
4
votes
1answer
50 views
Performing Esri NAD27 to WGS84 datum transformations with ST_Transform in POSTGIS
I am trying to align with some data points that have been projected in Esri from NAD27 State Plane feet (SRID=32026) to Lon/Lat using the "NAD_1927_To_WGS_1984_6" datum transformation using ...
1
vote
1answer
36 views
Layer is being add to 2 groups instead of 1
I'm trying to create 3 group layers, depending on parameters of two lists, but reg_imobiliarios layer is added to auxiliar and referencia groups.
In short, all the layers are in the correct group, ...
0
votes
1answer
47 views
ST_Intersect is giving wrong polygon back
I imported the french IRIS dataset by shp2pgsql.
Added LAMB93 to the PostGIS spatial_ref_sys.
shp2pgsql -W latin1 -I -s 97527:4326 CONTOURS-IRIS.shp iris20 | psql -d iris20 -v ON_ERROR_STOP=1
So ...
2
votes
1answer
76 views
How to increase a PostGIS query efficiency when querying OSM information
I have this SQL query to get roads from my PostGIS server.
WITH boxed_roads AS
(SELECT * FROM "planet_osm_line"
WHERE ST_Within(way, ST_MakeEnvelope(xmax ,xmin, ymax, ymin, 4326))
)
SELECT ...
3
votes
3answers
86 views
Find islands using PostGIS
I'm trying to find islands (type not water, completely surrounded by water) in a polygon table. The polygons are not overlapping.
Data:
CREATE TABLE islands (
ID serial PRIMARY KEY,
type ...
1
vote
1answer
37 views
Calculating list of existing polygons with distances from newly created QGIS/PostGIS
I have two polygon tables (SRID=4326) in postgres: t_areas and t_sites. Once I insert through QGIS 3,8 a new area in t_areas I'd like PostGIS (by a trigger) to list all sites within a certain km range ...
2
votes
1answer
80 views
Invalid Geometry - Which column can I change to geometry?
I have a csv file with thes two columns (amongst others): localisation and geo_point_2d.
Here is the content of one cell of localisation :
{"type": "MultiPolygon", "coordinates": [[[[-53....
5
votes
1answer
50 views
Calculate volume of MultiPolygon Z using Postgis
I am trying to calculate the volume of a multipolygon z using Postgis.
SELECT ST_Volume(geom) from grb;
And I get this error:
MultiPolygon is invalid : Polygon 0 is invalid: points don't lie in ...
4
votes
1answer
68 views
What is being filtered?
I have a Postgres/postgis table of polygons. When added to QGIS the total feature Count is 64671 in layer tree and attribute table. But the attribute table also says Filtered: 43573. I have not ...
1
vote
1answer
43 views
Convert a SQL Server Geometry into PostGIS spatial data with Python and shapely
I'm trying to migrate spatial data from a SQL Server database to a PostGIS database with Python. I need this to be automated since its not just one table, but a lot tables in a lot of databases.
I am ...
-1
votes
0answers
24 views
I got this error : elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison [closed]
rint(sf.columns)
se=float(numb1.get())
cur.execute("select distinct nassereddine_carte_gouv.c_gouv from nassereddine_carte_gouv,disshp where nassereddine_carte_gouv.c_gouv=disshp.id and Shape_leng &...
6
votes
2answers
141 views
QGIS and PostGIS, dimensions problems
I have a point-layer i Postgis v12 which is ST_point, ST_NDims = 3.
When creating a new point i QGIS and then tries to save it, I get an error:
Column has Z dimension but geometry does not
When ...
1
vote
0answers
21 views
Using Odoo as a database for QGIS
Is it possible to link an Odoo database (CRM) into GGIS? I have an online Odoo Studio account with lots of data including long/lat data etc. Is it possible to link the Odoo database directly with Qgis ...
2
votes
1answer
32 views
Find path containing point
In Postgres with PostGIS extension, I try to figure out to find the path containing a specific point:
table A contains POINT
table B contains PATH
My code returns 0 rows when it should
select * ...
0
votes
1answer
50 views
Verify PostGIS connection, username and password
I wrote the code below, but I need that the PostGIS connection to be verified, to be sure that the username and password are right.
I tried this: How to access user credentials in database connection?
...
2
votes
1answer
40 views
PostGIS: Extract intersected areas with their related column values
I have inserted a MultiPolygon table in PostGIS with the following columns:
id, e_id , p_id, com, geom
Assume that I have 4 polygons with overlapped areas with the following values:
id com geom
1 ...
4
votes
1answer
85 views
How to create Polygons of a specific size?
I'm trying to create polygons of specific size in square meters that represent the areas surrounded by roads. The roads are stored in PostGIS as points / lines. If required, I can convert the data to ...
0
votes
0answers
24 views
How to create a clean-graph/network layer to be used in Offline Map-Matching algorithm in QGIS
I want to use the Offline Map-Matching algorithm in QGIS to match GPS trajectories with a road network. This road network layers needs to be "a clean graph following a node-edge-model, i.e. different ...
0
votes
1answer
42 views
Load all SRTM data into PostGIS
I am trying to load all the SRTM data into a PostGIS database. I tried the process described here: https://postgis.net/docs/using_raster_dataman.html
It created a giant SQL file. When I tried ...
0
votes
1answer
41 views
How to check “simplification sensibility” of a geometry?
It is expected that a "geometry simplification" is a good practice to preserve stable versions of a geometry, avoiding minor and non-relevant changes (side effect of geometry-editors and other "false ...
1
vote
1answer
47 views
Finding points closest to latitude longitude point using PostGIS
Right now I have a data base with PostGIS. Several of the data sets contain different locations at latitude longitude points. I will be doing several queries based at different latitude longitude ...
1
vote
2answers
44 views
PgRouting coverage area with node restrictions
I have a water network in which there exist valves at nodes between two edges (pipes). When the valve is open water can flow, if not, it can't.
How can I calculate the catchment area from a start ...
0
votes
1answer
36 views
Importing Shapefile to PostGIS using QGIS DB Manager
I am trying to import a shapefile from my QGIS project to my PostGIS schema using DB manager.
I want to create a new table in my public schema and I have an ERROR: relation "spatial_ref_sys" does ...
0
votes
1answer
55 views
QGIS 3.10.2 - Install PostgreSQL and PostGIS
QGIS 3.10.2 in Ubuntu 18.04.
I'm having problems installing PostgreSQL and PostGIS following the instructions here: Installing PostGIS under Ubuntu.
This doesn't work, 'postgresql-9.1-postgis' isn't ...
0
votes
0answers
27 views
How to work in the form of QGIS PostgreSQL fields which is of type array[]
I have a table in a PostgreSQL / PostGIS database where there are columns of type array [] and I would like to know how to work on the QGIS form.
Example: I have a column called "WALLS" and that ...
3
votes
0answers
48 views
Function to make a trajectory more straight
I'm new at PostGIS and I have to do a project for my university course.
I'm trying to analyze a trajectory of points that I downloaded from my runtastic app but it's a mess.
There are some points ...
2
votes
1answer
35 views
ST_Intersects with multiple geometries
I am just learning PostGIS and have a simple problem I can't get the answer for.
I want to select the geometries that intersect with given multiple geometries.
To make it simpler, let's say I want ...
1
vote
1answer
54 views
Creating precise shapes using list of coordinates?
I am using st_concavehull to create boundaries/shapes. This works, however, the shape is not precisely tracing the coordinates. It is more puffy, as if trying to even out or "clean up" the actual ...
0
votes
0answers
20 views
pgr_dijkstra ERROR: invalid memory alloc request size 1080000000
I am using pgr_version 2.6.3
I tried googling, most of the posts suggest the data is corrupted. So I tried pg_dump and select row by row to try finding the corrupted row, but did not encounter any ...
3
votes
0answers
37 views
PostGIS:Fixing tiny polygon features
How to write a query in PostGIS to check and fix case in picture:
In the element_polygons I store the geometry geom.
1
vote
0answers
29 views
Data missing while importing .kml file to PostgreSQL using ogr2ogr
As I am newbie to both dealing with KML and PostgreSQL.
I am able to load KML file to PostgreSQL. But feature data table is empty. My file structure is same as mentioned in link.
while importing ....
0
votes
0answers
20 views
Interpolation of point data (postgis, geoserver) [duplicate]
I have a table in postgis with point data. A geoserver sql view layer is used to show a subset of these points (according to user selections).
What I want is do is to interpolate these points (...
2
votes
1answer
24 views
Calculating Geoid Height (e.g. EGM2008) for Lat/Lon in PostGIS
Is there an existing method or best practice for calculating Geoid height for a lat/lon location in PostGIS? I don't believe there is an "ST_" function.
I know that PostGIS makes use of ...
1
vote
1answer
36 views
Dealing with PostGIS WKB in PyQGIS
From QGIS I am running analysis on linestring geometry in PostGIS, and the result is updated geometry. I want to update the linestring only in editing mode of QGIS layer, so the user can decide ...
0
votes
1answer
46 views
Calculate average of the temperature value from 4 surrounded points in PostGIS [closed]
There are two-point tables. One includes temperature value and the other does not have this information. I would like to calculate the average of the temperature for the 2nd table based on the four ...
1
vote
1answer
29 views
Should ST_OrientedEnvelope results differ depending on order of transform?
I have a PostgreSQL db with a table with geometry multipolygons stored in srid 4326 (lat/lngs). I need to calculate the area of the oriented envelope around each polygon, and I am using ...
2
votes
1answer
38 views
Cannot convert shapefile data to PostgreSQL/PostGIS using ogr2ogr
I am a starter to use command-line interface. I was looking for a way to import a shapefile into PostgreSQL using "ogr2ogr". I was able to do this for point shapefile using code:
ogr2ogr -f "...
4
votes
1answer
37 views
Postgis/Postgresql - Interpolate equadistant points based on weighted attribution similar to QGIS Interpolation(Heatmap Kernal Density Estimation)
I have equadistant vector points, that are all 400m apart but only cover certain areas of a map that have a value of (1-5). In QGIS I can run the Kernel Density Estimation with my vector points to ...
-2
votes
1answer
25 views
Draw trails/paths in CARTO
I'd like to overlay a trail or path on the map. I have the gpx set of points and I'd like to draw a path on the map.
0
votes
1answer
71 views
Which map projection is suitable for distance measurement purpose in USA?
I'm developing an application which uses PostGIS functions for measurements in the USA. In nutshell: the software is running in a car and use PostGIS functions in real time. For example: to measure ...
0
votes
0answers
19 views
ArcGIS, reproject a PostGIS feature class causes the LYR file to show the feature class as empty
My client has ArcGIS 10.2 and PostGIS with features classes in them. They also have a lot of LYR files that point to these features classes. When I reproject the features classes in PostGIS, the LYR ...
2
votes
0answers
54 views
Cannot create extension postgis_raster on CentOS 7.6
I am using CentOS 7.6 at work. One one server I have PostgreSQL 12 and PostGIS 3 installed from the pgdg12 repo. This is working fine for vector data, but now I would like to use it for raster data as ...
7
votes
2answers
140 views
Aligning line with closest line segment in PostGIS
I've got a road network dataset and a dataset that consist of multiple disconnected lines of varying lengths in PostGIS.
Most of these lines are (largely) parallel to the road network, but the ...
1
vote
0answers
48 views
Run PyQGIS script always - in the background
How to always run a PyQGIS, in the background?
In my case, I want to delete "feature A", the polygon, that have a "attribute X", if feature B, the lines, that have "attribute X" as well.
2
votes
3answers
42 views
Populate an empty raster with values from intersecting vector layers
I'm looking to populate a large, empty Unsigned 8-bit raster with integer values 1 to 10. The value depends on the spatial relationship between a given raster cell and a variety of vector layers (...
2
votes
3answers
130 views
Simplifying a multipolygon into one polygon respecting its outer boundaries
I have a multipolygon containing a one large polygon, itself containing a number of smaller polygons, which constitute 'holes' in the largest polygon.
My goal is to simplify the multipolygon into one ...
