All Questions
38,069
questions with no upvoted or accepted answers
1
vote
0
answers
115
views
How to display label in center of symbol when using Points Displacement in QGIS
I have been attempting to display all the locations of some facilities I have to map. Due to the lat/long coordinates, they are overlapping. Therefore, I tried using points displacement when choosing ...
1
vote
1
answer
60
views
SRTM resolution increase (~88m to 30m) causes a windowpane check pattern in subsequent hillshade, aspect, slope, etc
I'm working thru QGIS trainings and ran into this:
Task is to use both a low-res Rainfall SRTM (32733) and a higher-res DEM/SRTM (4326) to produce rainfall, slope, and aspect layers, combine them, ...
1
vote
0
answers
115
views
PostGIS ST_ApproximateMedialAxis producing odd results
I attempt to get the centre line from a simple polygon (centre line is ambiguous; but I need a line through the centre of the polygon whatever the shape: the shape is always a long buffered line ...
1
vote
1
answer
434
views
How to convert convexhull polygon from geodataframe to shapefile
I have a point geodatafram with a classcolumn. I wanted to make a convexhull for each class and then write it as a shapefile. but I got error to convert it to shapefile.
print(gdf.head())
Convexhull =...
1
vote
0
answers
813
views
PostGIS: ST_Transform error
I have a table (tbl1) containing POINT geometries in EPSG:27700 (British National Grid).
SELECT id, ST_AsText(geom) as geom FROM tbl1;
=
id | geom
------+--------
1 | POINT(363179.79 176400.12)...
1
vote
0
answers
68
views
Exporting map to PDF using PyQGIS freezes the CLI
When I try to export PDF using PyQGIS 3 API the CLI freezes when the execution reaches the exporter.exportToPdf(pdf_fpath,exportSettings) call, and no PDF is exported. even though I can export the PDF ...
1
vote
0
answers
119
views
Display line with color gradient (or fade effect) based on the value of the vertices it connects
I have two vertices connected by two lines (we can assume way out and way back from point A to point B). In the picture I represented the lines with two arrows curved by adding a midpoint and its ...
1
vote
0
answers
53
views
Topolgy vs simple features
I'm starting using PostGIS, and then I found the main extensions of it, Simple Features (postgis), Topology (postgis_topology), Rasters(postgis_raster).
The Topology extension is great, in some ...
1
vote
0
answers
167
views
QGIS Graphical Modeler - Using field calculator to add values to point grid
Using the QGIS Graphical Modeler, I'm trying to add values from a raster previously generated in the same model to a point grid generated in the same model as well. I know I can do it using another ...
1
vote
1
answer
114
views
Refresh PostgreSQL table to show new fields
I have PostgreSQL/PostGIS tables and am adding fields in DB Manager. I have to remove and add the tables to QGIS for the new fields to appear.
I have tried:
Reload table (the icon in the attribute ...
1
vote
0
answers
63
views
Can ArcGIS Pro read the labels in shapefiles created in QGIS?
Can ArcGIS Pro read the label placement, label formatting and colors in shapefiles created in QGIS?
1
vote
0
answers
43
views
How to align drop-down display in a QGIS dock plugin
I have made a QGIS plugin using the dockwidget display mode. The GUI is made with Qt Designer. It contains a few dropdowns, one of them for layer selection.
It's working really well, but when the ...
1
vote
0
answers
942
views
Upload shapefile to GeoServer using JavaScript REST API
I am trying to programmatically upload a map into GeoServer as a layer.
The user requirements as such that this data has to be uploaded from memory directly into GeoServer, using JavaScript.
I looked ...
1
vote
0
answers
86
views
v.to.3D failing in QGIS
I'm trying to use v.to.3D in QGIS to create lines with proper elevation so I can export it to DXF. However, I'm running in to some issue when using v.to.3D. When googling I have seen others asking the ...
1
vote
0
answers
25
views
QGIS report: picture rotation does not work properly
In my report shown in the picture below, I’d like to add a red arrow (as a picture) on top of the north arrow to visualize the direction I took the picture from. I added a integer field to my point ...
1
vote
0
answers
265
views
Points in Polygon extraction
I have a shapefile with MSK-16z2 crs and a las-file which crs can not be recornized by qgis, but attached to the las prj contains also MSK-16z2. I need to crop described lasfile by shapefile. I tried ...
1
vote
0
answers
94
views
QGIS cannot find transformation grid
When I open an existing QGIS project I get an error bar at the top of the mapping window stating that some data cannot be projected (see below).
I can click on the details button and I get the ...
1
vote
0
answers
113
views
QGIS Print Layout attribute table source as model output
I have created a model which extracts features from larger shapefile databases around a site boundary. Each time I run the model I am using a different site boundary, however the outputs have the same ...
1
vote
2
answers
538
views
GeoServer changing raster color as scale changes
I have a Sentinel-2 image published on my GeoServer.
When I preview the layer, I can see it changes coloring somehow as I zoom in / out.
You can see examples in images below (look at the scale values ...
1
vote
0
answers
201
views
KML file saved with wrong CRS how to remove the layer shift?
I have the topography layer with the British National Grid CRS EPSG 27700.
Unfortunately, the KML data represents the other CRS - EPSG 4376 WGS 84.
It's sure-fire, that the data will be shifted ...
1
vote
0
answers
88
views
After splitting a line into 3 equal parts, the resulting parts are non-continuous
I have lines that I want to split into 3 equal parts, in order to check that my sampling points are in the last third of the line.
I used the editor and the split function as shown in the photo 1, the ...
1
vote
1
answer
487
views
Getting user input value from ArcGIS web app
I want to have user input an integer value which can then be used in an Arcade expression (for example in a popup menu).
Is there a way to do this on
ArcGIS Online?
I am looking for a solution that ...
1
vote
0
answers
631
views
Converting dbf to shp with QGIS
I want to transform dbf to shapefile with QGIS. I see the polygons in QGIS, but when I try "export", "save as", or from Toolbox "Extract/Clip by extent" - I see the ...
1
vote
1
answer
1k
views
What are the higher-resolution tracks on the ocean floor in Google Earth?
In Google Maps, the oceans are crisscrossed with what looks like slightly darker lines and patches. Zoomed in, they appear as thin tracks and whole tiles of higher-resolution imagery, with detailed ...
1
vote
0
answers
197
views
Create Buffers that are contained within a polygon with shared attribute
I'm using ArcGIS Pro to try to solve this problem. I'm mildly competent in ArcPy but have not attempted to script this. What I would like to do is create a buffers that stay contained within the ...
1
vote
1
answer
1k
views
Combining .tif files into multidimensional mosaic raster for analyzing change using ArcGIS Pro
I have a bunch of .tiff files with lichen cover data, one for each three year period from 1986 to 2021, and I want to use either (or both) the Analyze change using LandTrendr/CCDC tools in ArcGIS Pro ...
1
vote
0
answers
43
views
Assembling output into one shape when loop is used in python script in QGIS3?
I’m writing a new processing script for QGIS 3 using a for loop in the code.
The "problem" is that if I try to iterate N times, N shapes are generated in output. I would like to have only ...
1
vote
0
answers
63
views
Layer extent value not matching with CRS extent
I want to clip a polygon layer to an extent of another polyline layer. I want to use extract layer by extent processing tool, I want to automatically fetch the extent of my polyline layer along with ...
1
vote
0
answers
614
views
Implementing Leaflet plugin "Leaflet.Control.Layers.Tree" in R leaflet
I want to use "Leaflet.Control.Layers.Tree" in my R script. I am using the leaflet R-package to draw my map. I found this great leaflet plugin: "Leaflet.Control.Layers.Tree".
How ...
1
vote
0
answers
49
views
Relate two tables with different number of entities
I want to join two layers: One which has information about the height and width of the wind turbines (fields to join) with only 4 or 5 entities or sometimes less, and the other is a layer with lots of ...
1
vote
1
answer
185
views
What could be causing ENMTML occurrence data problem - undefined columns selected?
Absolutely loving the ENMTML package for really making thoughtful choices for ecological niche modeling! Until I came across this problem with a single species occurrence dataset that I just can't ...
1
vote
0
answers
54
views
"no data" result from raster calculator
Am trying to implement the following line in QGIS raster calculator:
("L@1" < 0) * ((1 - 16 * 200 / "L@1")^0.25) + ("L@1" >= 0) * 1
Basically, when L is less than ...
1
vote
1
answer
987
views
Why is GeoServer 'Layer Groups' not opening?
I want to create a layer group in GeoServer, but when I click on the layer group I get the error below. I am logged in as an admin, I'm not sure if this has to do with my setup?
An error occurred ...
1
vote
0
answers
253
views
put marker on a vector layer / map Qt-Qgis
I am designing a GUI using Qt and QGIS and showing maps (shapefiles - Vector layers) on the GUI. I want to put a marker on the vector layers when I click somewhere on the map. I could get coordinates ...
1
vote
0
answers
19
views
Is there an equivalent term to 'imagery' in context with maps and cartography?
Is there an equivalent term to imagery in context with maps or cartography?
Mappery seems not to exist. (I'm from Germany, and some miles away from being a native-English speaker)
To explain that a ...
1
vote
0
answers
510
views
Batch adding of SEGY files to QGIS
I am working with a set of legacy Archaeology GPR data that contains a massive batch of .segy files. Each file has multiple layers forcing me to "Select Vector Layers" to add. Is there a way ...
1
vote
0
answers
1k
views
How to query a specific layer from a feature service?
I am trying to get the list of feature service which has a specific layer (for example: River (the layer id is 0)) from a feature service,
from arcgis.gis import GIS
gis = GIS(url='https://pythonapi....
1
vote
1
answer
85
views
Measuring flight activity (in vector lines) of bird within boundary using raster analysis
I need to find out the time a bird spends in different areas within a windpark.
I have a shapefile (flight lines) with the following attributes:
"presence" is always = 1, the times ...
1
vote
0
answers
77
views
GeoPDF added into QGIS gives a broken raster; GeoReferencing it gives an invisible output
I've been attempting to add a GeoPDF to my QGIS 3.16.14 project. The PDF is available here: https://reliefweb.int/sites/reliefweb.int/files/resources/reach_irq_map_mosul_city_reference_08nov2017.pdf
...
1
vote
2
answers
72
views
Which quantile calculation method(s) does GRASS-GIS use?
Per Wikipedia , there are 9 common methods of calculating quantiles in common use across various statistical software packages, as well as languages like R and Python. Various other custom ...
1
vote
0
answers
195
views
Two layers have the same projection but different units
Two of my layers aren't aligning even though they're in the same area and use the same projection system. I am not sure why they won't align but I think it is maybe because they have different units ...
1
vote
0
answers
111
views
Setting mesh layer visibility in QGIS application?
I am utilizing the QgsMeshLayer class to load a NetCDF file that contains multiple variables (temperature, velocity, etc). I want to be able to set the visible dataset by variable name. I know how ...
1
vote
0
answers
125
views
Configure layer in MapServer 7.2 with 2 dimension (time and depth)
I am trying to configure MapServer in order to serve a vector layer with 2 dimensions (time and depth) using a tileindex shapefile.
In the mapfile I define the main layer and the tileindex layer as ...
1
vote
0
answers
660
views
QGIS 3.22 incorrectly displaying raster layers
Today, QGIS 3.22 incorrectly displays raster layers - by which I mean significantly in the wrong place and at the wrong scale. Moving the map with hand and zoom tool shows inconsistent updating (by ...
1
vote
0
answers
359
views
Cluster & Average linestring based on similarity
I am looking for a way to find the "average" linestring of a set of linestrings using postgis 3. Ideally the collection of linestrings should be clustered based on their similarity (Perhaps ...
1
vote
0
answers
3k
views
How to map 9-digit ZIP (ZIP+4) codes to census tracts?
The U.S. Department of Housing and Development provides a crosswalk between standard 5-digit ZIP codes and census tracts. This is a hard problem, as neither set's units are contained in the others'. (...
1
vote
0
answers
512
views
What units are the stream initiation threshold in the SAGA channel network plugin in QGIS 3?
I am using Qgis 3 and creating a Depth to Water (DTW) model and I am using NAD83 UTM 20. One of the steps in the creation of this model is delineating a stream network. In order to do so, I need to ...
1
vote
1
answer
211
views
Classify pixels using deep learning is giving wrong result for Landsat-7 data in ArcGIS
I am trying to classify two LULC maps from two data. One is for 2020 (Landsat 8), and another is for 2000 (Landsat 7). The pixel depth is 64-bit and both of the data were downloaded from Google Earth ...
1
vote
0
answers
186
views
Adding a layer by URL without knowing the layer type In the ArcGIS API for JavaScript
We are providing a service with a map using the ArcGIS API for JavaScript. One of the features that we want to provide is the ability to add any web hosted map layer to our map as a map overlay. When ...
1
vote
0
answers
474
views
Export QGIS layout as georeferenced PNG image with PyQGIS
I am using PyQGIS to export a map layout like this
exporter = QgsLayoutExporter(layout)
settings = exporter.ImageExportSettings()
settings.dpi = 100
path = 'C:/data/test1.png'
exporter.exportToImage(...