Unanswered Questions
21,382 questions with no upvoted or accepted answers
19
votes
0answers
537 views
SNAP vs. GDAL vs. Orfeo - image rescale, histogram cut
I work with a Sentinel-2 .jp2 image (red band, 10950 x 10950 pixels). My aim is to reach the same result what SNAP does with a Python script. See the SNAP method and parameters:
So this is my ...
18
votes
1answer
522 views
Determining flow path length in QGIS?
I need help with qgis flow path length.
I try to run the program and when I run the program I get a raster with 0 values, as input I'm using filled raster, I don't now if I'm doing something wrong or ...
18
votes
0answers
1k 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
1answer
439 views
rMaps choropleth with custom json
With R I want to make an animated choropleth map with the rMaps package and a custom map. I tried to follow the example of Diego Valle described here and to use the custom map info for Datamaps.
...
15
votes
0answers
435 views
Showing startup-messages on QGIS splashscreen
During the startup of QGIS, there are status messages shown in the lower part of the splashscreen like "restoring loaded plugins".
I am using a startup.py feature from which I would like to inform ...
12
votes
1answer
240 views
Matching segments of different lengths
I'm trying to match small segments with a larger segment they are the most probably related to: relatively close, similar bearing, and facing each other.
Here is a typical example of the data I have:
...
11
votes
0answers
460 views
Alter Minimum Bounding Box Algorithm
I'm trying to create an algorithm similar to minimum bounding box (though it may end up looking nothing like it). In this case the angle will be passed as a parameter and given the angle I need the ...
11
votes
0answers
587 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, ...
10
votes
1answer
2k views
Plotting bar charts on maps in R?
I'm using plotrix in R to plot a state level map of the US. It has an excellent function floating.pie to put pie charts on each state.
I'm wondering if there are similar functions within the plotrix ...
10
votes
1answer
863 views
Merge adjacent polygons and return all (adjacent and not adjacent) as Multipolygon?
I have a postgres database with administrative boundaries and their geometry.
Each of those boundaries have an ident number.
What I want to achieve:
First I want to select all rows which are ...
10
votes
0answers
683 views
Simplify the straight sections of (multi)Linestring in PostgreSQL/PostGIS leaving the curved sections untouched
I have (multi)linestrings containing upwards of 5000 points and I want to perform two simplifications possibly using Ramer Douglas Peucker or alternative methods in PostGIS. The (multi)linestrings ...
8
votes
0answers
319 views
Executing bidirectional dijkstra on TIFF image?
Can anyone indicate an example of how to do this? Link, tutorial etc...
I started a discussion here about how to load a TIFF image like a graph nicely answered by @sehe.
But, in this post the image is ...
9
votes
0answers
261 views
Cannot Open VRT of Sentinel2 image created by AutoCreateWarpedVRT
I am trying to create a warped VirtualRaster of a Sentinel2 image. Here the Python code I tried:
from osgeo import gdal, osr
srs = osr.SpatialReference()
srs.SetFromUserInput('EPSG:32632')
gdal....
9
votes
0answers
398 views
Accessing existing instance of QGIS from stand-alone python script
For my own data analysis pipeline, I am running a split screen setup with iPython notebooks on one side, generating variables from source data, pushing them to a CSV file which QGIS then reads/joins ...
8
votes
0answers
143 views
When using QGIS join by location, how does QGIS determine the first located feature option?
I have used QGIS process 'join attributes by location' in one of the models I have built and I have now been asked to explain in detail exactly how the model is determining the results.
I am using it ...
