Unanswered Questions

32,742 questions with no upvoted or accepted answers
32 votes
0 answers
3k 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 ...
17 votes
0 answers
817 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, ...
16 votes
0 answers
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 '...
15 votes
0 answers
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. ...
14 votes
0 answers
627 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 PostgreSQL ...
13 votes
0 answers
536 views

Remove reference to raster layer object PyQGIS

I am developing a plugin to load a set of raster files on QGIS. When there is a large number of files to be loaded, the main UI freezes. So I use QgsTask to move the creation of raster layers to a ...
12 votes
0 answers
393 views

Accessing watershed boundary for lakes in R

I have had success accessing unique database IDs and polygons for various lakes in the US. I'm now looking to get polygons for the watersheds associated with these lakes, but have stumbled a bit. ...
12 votes
0 answers
270 views

Processing post-execution script hook to clear scratch layers?

I've been cobbling together some Processing scripts for QGIS 2.18 (I'm not a fan of QGIS 3 scripts), and I keep running into one particular problem: my script creates a lot of scratch layers and they ...
12 votes
0 answers
504 views

MapScript with Python 3

I am trying to build raster summarizing features into a GeoDjango webmap, and would like to use the django-raster and django-wms packages to do so. I believe that I have them set up correctly, but am ...
11 votes
0 answers
1k views

Making polygon for every point in set using Voronoi diagram

I'm trying to make polygons from points, where each point will be represented by one polygon. I tried using Voronois, but the results are incomplete. While I more or less understand where this ...
11 votes
0 answers
361 views

Multithreaded DB connection for QGIS plugin

I am using QGIS 2.18.21 and PostgreSQL 9.6. on a Windows 8 machine. I am trying to do processing of a certain database task in the background, and I want the user to be able to continue to work in ...
11 votes
0 answers
296 views

ESRI Runtime Geodatabase Shape storage

Does anyone out there know the geometry storage encoding for ESRI's Runtime Geodatabase (.sqlite) format? aka mobile geodatabase. There are 'GDB_ tables', 'st_ tables', 'RTREE indexes' and other ...
10 votes
0 answers
230 views

Saving ArcGIS Pro symbology to PostGIS DB for each layer

I want to have a default style/symbology assigned to each layer in a PostGIS database so that whenever it is loaded in ArcGIS Pro, it will come up with the default style. There is a way in QGIS to ...
10 votes
0 answers
533 views

PyQgis Exporting Print Layout: "ERROR 6: The PNG driver does not support update access to existing datasets."

I am trying to export a .tif loaded into a pre-configured print layout template and further exported as .png def openLayer(project, fp, basename, vector=True): layer = QgsVectorLayer(fp, basename) ...
10 votes
0 answers
371 views

PyQGIS script crashes QGIS 3 when removing a custom pluginLayer which has custom legend

I upgrade a 2.18 plugin to 3.4. PluginLayer has been refactored and I could not create a custom legend as simple as previous major version of QGIS 2 : QgsDefaultPluginLayerLegend was removed. Use ...

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