Geographic Information Systems

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QGIS is a cross-platform GIS application licensed under the GNU General Public License.

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33 views

QGIS - Inaccurate field calculator

When I retrace a polygon using the measure area tool and get what I believe to be an accurate area measurement. However if I utilise the field calculator within the attribute table to calculate the ...
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1answer
21 views

QGIS: Clipping a Vector layer line on a another line?

Currently I have some Profile lines that have been clipped based on polygon layers which created some temporary lines, but right now I am trying to clip the total profile with a temporary merged line ...
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30 views

Feature is visible in a layer but geometry is None in QGIS using Python

I am using the feature's geometry in a layer to get the centroid point of the polygon. One particular feature is visible in a TOC layer and also able to select a feature. But, while reading that ...
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1answer
67 views

Clip polygon with nothing more than a point as starting point

Quite a straightforward question: I have a point layer that consists of a few thousand points. These points are heterogeneously positioned in or very close to polygons that are water bodies. These ...
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32 views

Open ArcGIS Business Analyst Vector Tile Service in QGIS 3.14

Don't even know if this is possible, but I am trying to open up a Vector Tile Service that is subscription content I have through Esri Business Analyst Online. I am able to open in ArcGIS Pro (of ...
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1answer
14 views

Get properties from a QGIS 3 RasterLayer like GDAL Driver Name/Description and the data type

How do I use python to find raster layer properties like The GDAL driver and/or description used to load a raster in QGIS For Example : for a Tif 'GTiff' and 'GeoTiff' or        for an ESRI Grid '...
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1answer
27 views

QGIS Symbology: how to make a symbol a shape according to a set of rules and a color according to another set of rules

I'm using QGIS 3.14 with GRASS 7.8.3. I have a data set with point coordinates on a plan (artifacts on an archaeological site). I have two main variables that I want to show. So, I'd like to have the ...
2
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1answer
41 views

Linking points with lines for display in QGIS

I have 2 point shapefiles which contain lat and longs and I need to connect these with a line for display, not analysis. I am using QGIS 3.4. To explain further, for one individual species/animal (i.e....
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1answer
18 views

Create an 'heatmap' based off of a numeric attribute in a point feature class [closed]

I have a shapefile with several points, each of which has a numeric attribute 'price'. I am trying to find areas that have the most potential revenue concentrated based off of the price in the feature ...
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18 views

After start editing, the editing toolbar remains inactive in QGIS

With respect to my previous question Disconnect editingStarted in PyQGIS , While doing some research for question, I found some details to stop editingStarted signal with following code. layer=iface....
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31 views

QGIS: How to speed up raster processing?

Is there any way to speed up raster processing in QGIS? I have seen discussion about speeding up rendering and querying, but not processing. I am using SAGA tools to calculate morphometrics and the ...
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1answer
25 views

Define point locations in relation to slope [closed]

I have a dataset of settlements that I would like to put in relation with slope and aspect layers that I have made to see if there is a preferred altitude or direction (facing north or south, etc.) ...
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1answer
23 views

Exported shapefile from selected features via PyQGIS is blank

I'm doing Open Source Options' tutorial on the topic but my code doesn't work. I guess the selectByExpression() works but writeAsVectorFormat() doesn't. This is my code layers = QgsProject.instance()....
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0answers
39 views

QGIS Slow Rendering

I have QGIS 3.12, running on Win 10 x64, with an i5-9600k cpu, 16GB DDR4 RAM 4000MHz, an NVIDIA Quadro P2000 Graphics card and very fast SSD (Samsung 970 EVO Plus 1 TB PCIe NVMe M.2). In QGIS, I have ...
2
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0answers
21 views

Attribute names changed in symbols after running distance tool

I'm struggling to understand why names in one column of my attribute table are changed into symbols after performing the distance to nearest hub (line to point) tool in QGIS 3. My reference shapefile ...
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0answers
12 views

Why does QGIS throw me an error on startup with processing.run? [duplicate]

I am trying to run python startup script for QGIS with the following code: from qgis.core import * from qgis.utils import iface import os from qgis import processing project = QgsProject.instance() ...
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1answer
46 views

Change default saving folder

Probably a basic issue, but still something that irks me and I can't find an answer online. I want to change the default folder for saving new shapes/processing outputs from "last used folder&...
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0answers
23 views

QField Create Geometry

I use QField for tree surveys. I use Geometry generator to create the crown (canopy) spread based on crown radius taken at N, S E and W. This works, but the crown is 'virtual' and cannot be edited. ...
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0answers
24 views

Use HTML legend in QGIS

I am trying to set up HTML text in a legend of this kind: <div style = 'padding: 0; margin-left: -10px; color: # 7f7f7f '> O-1 <span style =' color: black '> - Kind of zone </span> &...
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13 views

Dynamic (auto-refreshing) import of a polygon attribute to a point lying within this polygon

I want to achieve something similar to what was discussed here. Except I would like this attribute to be automatically updated if I change the attribute of a polygon (its name specifically) or move ...
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0answers
14 views

QField Photos and External Storage

I'm using QGIS 3.12 and QField 1.5.3 on a Samsung Galaxy S4 (Android 9). My project allows collection of photos. This works when stored on Internal Storage, but not when stored in 'QField directory on ...
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14 views

QGIS Terrain Profile Plugin: Getting the X and Y coordinates of the XY axis of the tool on the graph with the 2D profile DXF for AutoCAD

I have already drawn out some lines (polylines) to use to get a terrain profile for each area, which I can export to as 2D profile DXF. However there is a something I am missing, I would like to have ...
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18 views

Using the QGIS graphical modeler to add 1m to every point of a raster and opening the output raster

I used the graphical modeler which is easy but when I want to use the exported python code in the Python console I don't know how to save and open the output raster. Here is the code I have : from ...
6
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1answer
126 views

English translations of QGIS commands, algorithms and menu items

For posting here at Gis.StackExchange, I often have to find the english equivalent of commands, functions, algorithms, menu items etc. of my german language version of QGIS. Sometimes, a word-by-word ...
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0answers
26 views

Strahler Order Error

I'm using QGIS (Zanzibar) for a project in my university and that includes finding the stream order and some shape parameters. So I tried using the strahler order to calculate the stream orders and ...
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0answers
21 views

Clip Raster By Mask Layer Error Message [closed]

When trying to Clip Raster by Mask layer I get this message. Running 3.10.7 on Mac with High Sierra Any help appreciated, thanks guys.
1
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1answer
43 views

QGIS3.10, Find all points that are located on a line

Inside my .shp there are two simple layer: "Points_Example" (Type: Point, EPSG:25832) "Lines_Example" (Type: Line, EPSG:25832) Some of the points are located exactly on the line ...
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18 views

How to set my own QDialog Form instead QGIS QgsAttributeForm

I'm working in a QGIS plugin which its functionality is to facilitate the creation of custom attribute forms with complex logic to QGIS users without python knowledge. In order to do this, the user ...
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0answers
17 views

Seeking plugin for QGIS to create iso-distance polygons longer than 120km

I'm new on QGIS and I have been using the ORS plugin to create isochrones and iso-distance polygons. However, through Openroute Service I cannot create iso-distances longer than 120km. Is there any ...
4
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1answer
60 views

Add basemaps in QGIS - what differs Tile Services from QuickMapServices QMS?

Environment QGIS-version: 3.14.0-Pi QuickMapServices Plugin: 0.19.11.1 I want to use background maps inside QGIS (QGIS version 3.14.0-Pi) and can do that by using f.e.: WebMapTileService (can be ...
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0answers
30 views

Selecting roads to use in Chinese postman problem

I'm very new to this. I'm using a QGIS plugin to solve the Chinese postman problem (shortest way to travel every street) and am having trouble selecting the roads for it. This is the plugin I'm using: ...
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2answers
47 views

Selecting only values that occur more than once in a field

I have a field that contains different values, some which occur more than once in the field. How do I select only the values that occur more than once? Example I only want to select rows that contain ...
1
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1answer
28 views

How to link array values stored in a layer to values stored in another layer

I am stuck for several days trying to get array values link together. I spent hours without getting serious results. I have a bus stop points table with arrays containing the bus routes numbers ...
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0answers
21 views

Trying to use the Least Cost Path plug in in QGIS

I am trying to calculate the least cost path among one central point (start point layer) and another layer made of several points, representing other sites (end-point(s) layers). I am using the Least ...
1
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1answer
35 views

Insert an input variable in a query in PostgreSQL

I'd like to insert an input variable (integer) in a query SQL (@variable) using the algorithm postgresql execute sql in the graphical modeler of QGIS. For example, in this kind of query INSERT INTO ...
1
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1answer
29 views

Process to calculate distance from points to line in QGIS [duplicate]

I am trying to calculate the distance between each point(as seen in the picture below) and its nearest line which is a road. I have tried to rasterize the data on all the roads and I end up with the ...
1
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1answer
29 views

Counting intersections between line and points using Field Calculator? [closed]

I'm using QGIS 3.12 and let's say I have a Layer that consists in Lines that represent 'Rivers', and I have another Layer that consists in Points that represent 'Bridges'. Can I count the number of ...
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0answers
20 views

Obtain length of polygon edges neighbouring a specific polygon type

I am on Qgis 3.12 I have a shapefile with land use polygons (forests, roads, meadows, etc...). The polygons are in one layer, and no polygon intersects another one. One of the field of the layer is a ...
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0answers
18 views

Can style be saved with Qpackage and how can the new .qgs use the new .shp locations automatically?

I've used the Qpackage plugin to move all the layers of a project to a new location. At first my try was to move the source files, but it seems to have made new files, which is no problem. But now it ...
3
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2answers
66 views

How to have an infinite colour ramp for a choropleth, in QGIS

I have a dataset of land values which, for the full range, is say 125 to 250,000,000, i.e for a whole state. For the user, they will only be seeing on the map canvas, a small subset of this at any one ...
0
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1answer
27 views

Attempting to Draw Electricity Grid - Need Maximum Segment Length and Precise GPS Coordinates

I am attempting to draw an electricity grid (poles and cables) using QGIS. I need to ensure that each pole is a maximum of 50m apart, and then I need to measure the total length of the grid and ...
0
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1answer
30 views

How to calculate mean of raster layers where some layers have missing values (R or QGIS)?

I am trying to create annual averages of some raster layers, but some of these layers have gaps in the data. If all pixels in all of the layers contained info I would just use Raster Calculator and do ...
3
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0answers
63 views

Aggregate attribute based on symbology classes in QGIS

I was wondering if there is an existing tool/way to aggregate an attribute based on the active symbology of a layer. For instance, if I have a point layer with population and distance from the city ...
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0answers
15 views

QGIS: dissolve with statistics (summarize) for several attribute fields in graphical modeler

I'm trying to dissolve a shapefile by one attribute field "HYBAS_ID" and I need the other fields to be summarized simultaneously. I've worked a lot with ArcGis and the dissolve tool there ...
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0answers
21 views

Remove layer indicator in QGIS

I would like to be able to change or remove the tooltip when the mouse is over a layer in TOC. I've seen in source code that i must to use the QgsLayerTreeViewIndicator class to perform it, but it ...
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1answer
41 views

Expression-based file name (ATLAS)

I have a Shapefile file with more than 2,000 elements, with its extensive table of attributes, and I have made a model file, through the Atlas, where a map appears with a zoom of each element and a ...
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0answers
24 views

Find the sequence/rank of lines (polylines) in QGIS

I have line shapefile with different bus routes (each route consist of multiple line), in which I want to sequentially arrange the lines for each bus route based on the direction of route. I tried ...
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0answers
16 views

QGIS: Spliting a geodatabase with its styles and data back to a normal zip folder: Without a third party tool

Currently we use a third party tool (mygeodata website) to convert our geodatabases back to a zip folder with all the contents of the Geodatabase and the styles intact (even the standard Style Setting)...
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0answers
19 views

Using SAGA tools on a subset of raster cells

I am calculating topographic position index (TPI) using SAGA tools for a DEM. TPI looks at the elevation of a raster cell compared to the mean elevation of raster cells in a surrounding neighborhood (...
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2answers
48 views

Measure Points to Coastal lines?

I would like to measure the shortest distance from multiple points to a any part in a coast line of three different costs. How do I do this with QGIS or with SAGA GIS?

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