Questions tagged [vector]
A coordinate-based data model that represents geographic features as points, lines, and polygons.
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0answers
17 views
Python: Convert shapefile to GeoJSON whilst stripping and renaming fields
I'm writing a Python script to convert shapefiles into GeoJSONs but I would like to remove many of the fields as they are redundant and rename the ones I am retaining.
Here's an extract of where I ...
2
votes
1answer
54 views
3-D Terrain effects for vectors in QGIS?
I'm a bit new to QGIS, and making a few maps of roads through mountains. I'm looking to have a 3-D effect within my 2-D map.
I got a DEM, made a hillshade, and blended a basemap over it. Nice ...
0
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2answers
28 views
Reclassifying vector polygons based on text string to integer using Python Parser of ArcGIS Field Calculator?
So I am trying to reclassify a text string by searching for bits of strings and converting those strings to an integer value in a new field within the field calculator. e.g. I want to find all values ...
1
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1answer
28 views
Calculating areas of polygons that match with overlapping raster threshold value?
I have a polygon of districts (districts.shp) and a raster of rainfall (rainfall.tiff).
I want to calculate the area of each district that saw rainfall greater than various numbers.
I'd like to ...
0
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0answers
18 views
Can only select certain polygons
I have only one vector layer on my map, and it's not letting me select some polygons. For instance, this is what happens when I try to select a certain polygon (the yellow outline with the blue star ...
1
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1answer
39 views
Map based on highest percentage from different variables
I've the 8 social classes (see under) for +- 900 polygons. I would like to create a new column that keep only name of the main social class for each row (based on the percentage). After that I would ...
0
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2answers
55 views
Seeking tool to work out overlap between two polygon layers and their statistics using QGIS
I have two polygons in QGIS. One is a land-use map, which polygons that include different types (forest, agriculture, urban etc). I also have a vector polygon that represents a flood extent. I want to ...
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0answers
48 views
Fixed distance buffer is oval in QGIS?
I want to create circles of diameter 20m in QGIS. I create a point and then use vector - geoprocessing tools - fixed distance buffer. My problem is that the size is crazy and worse, the shape is not a ...
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0answers
21 views
Computing Moran's I for vector data in GRASS
Does GRASS allow for computing Auto-Correlation using Moran's I statistic from vector files. GeoDa and ArcGis can do this. But seems grass lacks this functionality
https://grass.osgeo.org/grass76/...
3
votes
1answer
48 views
Fixing self-connect polygon in QGIS 3.2
I'm trying to clip a soil map layer and am getting invalid geometry that affects my clip result. The problem appears to be a self-intersecting polygon.
I've tried using the 'check geometries', and ...
0
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2answers
65 views
How to convert multiple shapefiles of different geometries into a georeferenced raster
I have multiple shapefiles extracted from OSM vector data, as shown in the image bellow:
How can I render this into a raster of a specified resolution? Is there a way to do that using QGIS or ...
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3answers
57 views
Converting raster pixels to vector cells?
Is there any way to convert raster pixels to vector cells?
I mean each pixel to a polygon.
I tried the SAGA tool 'Raster values to points' by choosing cells option instead of nodes option.
As a ...
0
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0answers
16 views
Clipping features with the attributes of another feature
I have a vector polygon for a catchment which contains numerous subbasins. In addition, I also, possess another vector polygon showing the impervious areas of the catchment.
What I want to do is ...
3
votes
1answer
61 views
Buffer with unknown distance by adding numerical values of a column until a maximum
In my QGIS project, I have a vector of polygons representing slope zones around an archaeological site and I want to calculate the area which is necessary to supply the ancient population with a ...
-1
votes
1answer
46 views
Summing amount of vector points in area of another vector using Google Earth Engine?
So I have 2 layers each are both vectors and not images. here the link:
https://code.earthengine.google.com/e7aec6c9683ed40a959a01a7ed5dd31f
I have written some basic code to display the data which ...
0
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0answers
51 views
Creating memory layer with .png image using PyQGIS?
In Aligning Raster and vector layer using PyQGIS when they do not match?, someone gave a solution for creating a point memory layer to correctly align a raster image with a vector.
I am wondering ...
2
votes
3answers
121 views
How can I save a vector layer to memory (or is there a reason QGIS doesn't allow this)?
It's impressive how many different vector file formats QGIS (using ver 3.6.0) allows me to save a layer as:
But as far as I can tell, QGIS doesn't allow me to save a vector layer to memory. In my ...
1
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0answers
116 views
PyQGIS raster image shifted from vector shapefile
I previously asked a question about my raster image being larger and shifted over from my vector image here, but now I realize that the raster image is only shifted to the left and up from the vector ...
1
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0answers
41 views
Storing a large amount of vector layers on PostGIS
I'm developing a web application where PostGIS will be used as a vector tile server backend to serve mvt tiles. For each user of the application at least one vector layer will be created. So, ...
2
votes
1answer
56 views
PyQGIS code for Merge Vector Layers
I've been trying to automate the merge vector layers via PyQGIS but I can't seem to get it right. This is my code:
import os
import processing
loc = r"C:\Users\loc"
os.chdir(loc)
shapelist = os....
1
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0answers
47 views
Can relation reference in QGIS and QField be used to fill stochastic matrices?
I am a novice GIS user and am just seeing the potential for relations in my work. A problem I've come across and would like a solution to it.
I have two stochastic matrices (risk matrices) that ...
4
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0answers
42 views
Referencing an output in an expression in process modeler
In the process modeler, I'd like to reference an output of a previous step as one of the parameters of an algorithm. In this case, the previous step was clipping a large raster and I want to use the ...
1
vote
2answers
61 views
Selecting latest date with QGIS field calculator?
My shapefile contains columns like "Street", "number" and "date".
What I want to do is, to find the latest date (where we have done house services). If we have 2 dates for one house number ("number")...
3
votes
2answers
69 views
QGIS how to sum a certain vector field inside a polygon and populate a field in the polygon?
I have a polygon with vector point civic addresses inside it. Each civic address has a different number residence. I want to sum the total number of residence inside that polygon and it populate a ...
0
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0answers
24 views
QGIS 3.4 (mac) std::bad_alloc error
I get the above error when trying to add a new raster or vector layer. Does anyone know how to correct it as the resulting projection is nowhere near where I need it.
0
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2answers
67 views
QGIS Hex grid with the shape of vector
I'm trying to make a hex grid net with the shape of polygon. Unfortunately, the grid net is in the rectangle shape (see the screenshot).
Any advice how to do it?
2
votes
2answers
44 views
Unite several polygons that share boundaries in QGIS
My study zone is in the middle of two geologic maps with two different shp files.
Is it possible to remove the boundaries of the polygons between these two maps that are created at the union of ...
2
votes
1answer
46 views
average weighted value by region with use of Voronoi in Qgis
I have a vector layer of Voronoi polygons. This layer has three columns -longitude, latitude, Z-value.
I need to cut polygons by mask of administrative area and then I need to calculate average-...
0
votes
0answers
22 views
Export vector graphic from ArcGIS？DPI setting？
When I plot the map in ArcGIS, I wish to export it to the vector figure. And the file is shapefile, no raster files loaded. However, when I try to export the Map. The setting from the window ask me to ...
0
votes
0answers
11 views
Get visible polygon form one point (visibility graph with one point)
Problem
I would like to get the visibility of one point in regard to a polygon layer. E.g. which island can I see from the beach.
What I found
It's possible to get a visibility graph via Grass v....
1
vote
0answers
114 views
Error in reproject vector file using GeoPandas
I have a vector file (in this case shp file) and I read it with GeoPandas (gpd).
vector_folder = r'C:\poly'
vector_file = 'poly.shp'
df = gpd.read_file(os.path.join(vector_folder,vector_file))
df
...
1
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2answers
62 views
Calculate the percentage of a Line passing through Polygons
I have a polygon layer of a region (100% coverage, no overlaps) and a line layer in the same region.
I want to calculate for each line to which percentage it crosses certain polygons.
I have seen ...
1
vote
1answer
65 views
Creating new lines based on another line feature and point feature using QGIS?
I have line layer (roads) and point layer (milestones) and I need to create a new line layer based on roads layer, where the start and the end points will be milestone points.
Can you advise me some ...
1
vote
1answer
124 views
QGIS 3.6: Vector “Polygons to Lines” missing
I use the tool Vector-->Geometry Tools-->Polygons to Lines all the time. It is in the menu up until 3.4. In 3.6, that menu item is no longer available. Where did it go? Is there another way to do ...
1
vote
3answers
63 views
Calculating the shortest distance coordinate to vector layer
I want to calculate the nearest distance from each coordinate in a vector layer containing more than 17 000 coordinates to another vector layer. I tried the GRASS v.distance tool but it gives the ...
3
votes
3answers
314 views
QGIS split vector layer gives me GPKG files but I need shp files
QGIS 3.6.0
I am new to QGIS software and not very technical on its deep workings. I am trying to split a .shp file using split vector layer. I need .shp file outputs but it auto creates .gpkg files.
...
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0answers
106 views
Does any version of QGIS support GDB 10.5?
Does any version of QGIS support GDB 10.5? I have a GDB 10.5 file that I need to open in QGIS and I can't. I'm using QGIS 3.6.
The file is named Virginia_Parcel_Dataset_2018Q4.gdb -- it can be ...
0
votes
0answers
40 views
ArcGIS: Train Support Vector Machine Classifier on a Segmented Raster
I have a raster (.jpg) which I have segmented utilising Segment Mean Shift to smooth out JPEG artefact (aim is to classify it as accurately as possible for conversion into vectors).
START .JPG
Input ...
0
votes
1answer
20 views
How can I keep the minimum when converting from shapefile to raster
I have a shapefile that I am trying to convert to raster. The shapefile has overlapping polygons. I would like to keep the minumum value of these overlapping polygons when converting to raster.
...
1
vote
1answer
78 views
How to make a rectangle of an exact size/aspect ratio in QGIS?
Is there any way in QGIS to make a vector layer with a rectangle of an exact size or aspect ratio? Ideally, it would be nice if the rectangle from extent tool could be limited to a set aspect ratio, ...
1
vote
0answers
81 views
Vector Rasterize Error
I am running QGIS 3.4.4 With GRASS 7.4.4 and I get an error while rasterizing a vector layer and I don't know why.
The same error pops up while using GDAL->Rasterize(vector to raster) and while using ...
2
votes
1answer
56 views
Translating vector by raster DEM data in QGIS?
I'm trying to follow the set of instructions here: https://twitter.com/imhere_asia/status/1023055838787690496
[EDIT]
Pasting the instructions here for reference so people can avoid twitter.
...
0
votes
0answers
21 views
Prevent Export/Save As of Vector Layers/Shapefiles
I have created a database using postgreSQL and created multiple users assigned with different roles
Some of the users can only select and view the data and not update or delete any record. It works ...
3
votes
1answer
115 views
Exporting crown boundaries from tree segmentation in R?
I am using lidR package to segment my trees using lastrees directly from the points clouds.
The function works fine, however I would like to export to vector file the canopy boundaries from ...
0
votes
1answer
71 views
How to batch geocode country names to polygons? [closed]
I have .xlsx dataset file with column "Country Name" and "Country Code" which have text records. I would like to geocode (assign) it to adequate country polygon in batch mode. The expected result ...
1
vote
1answer
35 views
QGIS3 How to export shapefile symbology to scale?
I'm looking how to export in QGIS3 a vector layer with a determined scale.
It was straightforward in QGIS2 when I was exporting to a shapefile I had the option symbology scale but it disapear in QGIS3 ...
8
votes
2answers
236 views
Create line segments at point coordinates in QGIS
I have a point vector layer with angle field. How can I create line segments at these points with certain length and angle?
I did this with style options but I need this physically as lines vector ...
1
vote
0answers
27 views
Vector to grid - Computing statistics by grid cells
I have a vector point data from drifting buoys (speed, direction, sst, slp) that I want to analyse in a grid. What are the right tools for this?
Example of my points data below. Each point has the ...
0
votes
0answers
41 views
QGIS Display Attributes as Z Value for Point Shapefile?
I would like to create a state map that displays a 3D bar chart for each of 20 colleges (mapped as points) showing the percent share of engineering degrees earned by award level (i.e., assoc, ...
1
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0answers
133 views
Modifying style (line width/color) of vector layer in PyQGIS?
I'm currently updating some python code from QGIS 2.18 to QGIS 3.4
in 2.18 i used the following code :
#First off I created a virtual layer using an sql query here
vlayer = QgsVectorLayer( "?query=....
