Unanswered Questions
28,954 questions with no upvoted or accepted answers
26
votes
0answers
2k views
Leaflet v1 plugin: layer control for ungrouped, grouped, and nested-grouped layers
I need a Leaflet plugin which extends L.Control.Layers. I have the following requirements:
works with Leaflet 1.x
handles ungrouped layers alongside grouped ones
handles nested layer groups
does not ...
16
votes
0answers
1k views
Digitizing in stream mode in QGIS using a tablet
How can I digitize in stream mode in QGIS, using a wacom cintiq tablet?
Freehand it's no use. I need something like MNDR stream digitizing extension for ArcView 3.x, which allows continuous tracing, ...
14
votes
0answers
205 views
Unit testing for QGIS 3 plugins
There is a nice resource on unit testing for QGIS. There is also a post on this, Writing automated tests for QGIS plugins, which requires the use of docker and relies on QGIS 2 plugin - QGIS Tester.
...
14
votes
0answers
723 views
Parsing file format for attributes in Raster Product Format (RPF) maps and imagery?
I'm trying to implement an open-source NITF reader (using only java, no external libraries such as GDAL or NITRO), and its mostly going OK. However I'm having trouble understanding the RPF extensions, ...
12
votes
1answer
474 views
Point cluster symbology for different categories without overlapping symbols
I'm trying to visualize crimes based on if the crime happened during day or night time. I've tried using the point displacement tool but I'm not satisfied with the results because the readability for ...
12
votes
0answers
1k views
Constructing a Voronoi diagram using a complicated travel time metric
I have in my possession four sets of shapefiles:
1. Locations (points), around 1000
2. Roads (lines), each road has a speed attribute
3. Terrain (polygons), each zone also has a speed attribute
4. ...
11
votes
0answers
364 views
High PostgreSQL/PostGIS memory and disk usage when saving QGIS project
Why would simply pressing the "save" button in QGIS cause my local PostgreSQL instance to cause memory and disk usage to spike to "Not Responding" levels? Seems to me like the ...
11
votes
0answers
407 views
Producing time-space cube in QGIS?
Although I have seen many examples about doing this at ArcGIS Desktop, I am still trying to find a how to using QGIS. What I want to do is something like the image below.
11
votes
0answers
2k views
Extract TopoJSON directly from PostGIS
I have a simple "region" table: id (TEXT), name (TEXT), geom (MULTIPOLYGON). Here's the query I can use to extract a GeoJSON FeatureCollection:
SELECT row_to_json(fc)
FROM (
SELECT '...
10
votes
1answer
5k views
C# implementation of concave hull / alpha shapes
I'm looking for a C# implementation of the Concave hull (alpha shapes) algorithm.
I already found several Java, Python and C++ implementation but no C# version.
The other implementation are quite ...
10
votes
2answers
7k views
Downloadable, Open Source, IP GeoLocation database
I have an open source project I need a similarly open source IP GeoLocation database for. i.e. IP address to country (and ideally city). Ideally with a license that allows redistribution.
This is a ...
9
votes
0answers
135 views
Reading raster backward using GDAL
I am currently working on two-scan raster algorithms (euclidean distance transformations, cost surface analysis, etc.). Those algorithms require a line-wise forward raster scan (from top left to ...
9
votes
0answers
344 views
Remove reference to raster layer object PyQGIS
I am developing a plugin to load a set of raster files on QGIS. When there are a large number of files to be loaded, the main UI is freeze. So I use QgsTask to move the creation of raster layers to a ...
9
votes
2answers
930 views
Shapely with Rtree versus STRtree
I have a huge interrogation regarding the performance difference between Rtree and STRtree included in Shapely. Below is a short code where we create randomly 250 000 triangles (defined by 4 vertice) ...
9
votes
1answer
2k views
Editing Layout-Items after loading a QPT-Template in QGIS 3 with Python
I am facing a problem with the new Layout API while implementing a plugin for QGIS 3.
Starting point is a layout template in qpt-Format, which contains different elements like (attribute) tables, map, ...
