Questions tagged [vector]

A coordinate-based data model that represents geographic features as points, lines, and polygons.

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3
votes
1answer
50 views

Calculating real length and slope of roads

I have collected points alongside road in form of csv files with z-values. When imported in QGIS I used Set Z value and Points to path to make line. When I use right button in Identify Features tool I ...
1
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1answer
30 views

QGIS 3.4 Rule Based Symbology - Exact Matches Integers in String e.g. 2,12 + 1,2,3,12

I have a shapefile containing a String Type Field called 'Class'. This field contains one or more integers separated by commas. I want to create Rule-Based symbology matching only 2, 12, 1 ...
2
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1answer
33 views

Shapefile to polygon, then edit the polygon in order to use it as a mold

I am working on QGIS with a shapefile: I transform it through Raster-> Conversion-> Polygonize Then I eliminate some parts (Sea), and those that are bigger than one single square of grid but are ...
1
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2answers
43 views

Clipping raster by mask layer with rule that it only clips raster if shapefile overlaps by 10% using QGIS?

I am using QGIS. Is it possible to clip a raster when the shapefile overlaps with it by 10%? Clip raster by mask layer tool is fine for Ontario (left) but makes me lose a lot of data from smaller ...
1
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1answer
33 views

Polygonize specific raster values QGIS

I have a raster of 36 classes of the land cover in South Africa. However, I only need 4 of these classes and create a polygon out of these 4 classes combined. I have now used the raster calculator to ...
4
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2answers
274 views

Density map of pedestrian paths and footways in QGIS

I need to identify public places within pedestrian areas in London, so I need to calculate the density of both pedestrian links and footways. I have classified my data according to the categorization ...
-3
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0answers
17 views

Edge detection to vector [closed]

How to Result Edge Detection, which is raster and has only one band convert to vector in google earth engine. I did the edge detection, and now I want to convert that result into a vector. How can I ...
2
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2answers
44 views

Summing Area of polygons within vector layer within zone using QGIS?

I have one vector layer with multiple polygons (purple). I also have a number of other vector layers which are catchment zones (I also have a layer where these catchments are merged). Is there any ...
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0answers
11 views
1
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1answer
21 views

Selecting a polygon area in a raster image - rasterio.mask vs roipoly

How should I select a polygon area in a raster image? So far, I have seen two methods: use a vector mask or a shapefile (some examples here: http://www2.geog.ucl.ac.uk/~plewis/geogg122-2011-12/...
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0answers
16 views

Running v.net.steiner in segments?

I am using GRASS GIS 7.6 on a CentOS server with 157 GB of RAM. The vector categories of the network layer that I need to run the Steiner tree algorithm on are as follows: Layer/table: 1/network type ...
4
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3answers
65 views

Counting number of polygons inside zone using QGIS?

I've seen a lot of questions about counting the number of points within a polygon but my question is I have 1 vector layer with polygons showing past landslides that have occurred and another 206 ...
2
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1answer
44 views

Error converting vector shapefile to raster (.TIF) in QGIS?

I am working with a shapefile of 10km grid regions of the UK obtained from digimap. I need to convert this to a raster in order to do some analysis in R regarding agricultural intensity of 10km UK ...
6
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2answers
3k views

Clipping Error 1: Cutline polygon is invalid

I used the sample files located at this URL to learn QGIS: https://qgis.org/downloads/data/. I tried to clip SR_50M_alaska_nad.tif using a shapefile as a mask (alaska.shp). The problem is I ...
3
votes
1answer
2k views

Why can't I clip my Shapefile?

I've tried all of these solutions (How to clip a line layer based on polygons with QGIS?) and still can't clip a shapefile. I'm trying to create a coastal shapefile for one region (NW France) from a ...
1
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0answers
11 views

Interactive tool for editing TIN data

I created TIN to generate DTM using Mass points from Lidar data and river data that I made from stereoplotting. TIN results show there are several locations where the river elevation floats. So I have ...
1
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1answer
85 views

Turning “normal” Vector Data into a GIS

I have a map in Adobe Illustrator with several vector layers. ( Therefore the vector data have no spatial reference and no attributes. What is the best way to turn these vector data into a GIS and ...
1
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0answers
33 views

QGIS freezes when trying to view layer properties

As of recently whenever I try to edit the properties of a vector layer the entire program just freezes and I'm forced to end the process using task manager. I use Windows 10. Any reasons as to why ...
3
votes
1answer
38 views

Creating DEM Contour files from shapefile line data in QGIS

There are many question occurring on this forum regarding this issue, however the issue I am facing has not been answered in Generating DEM from contour Shapefile using QGIS?, which is that I have ...
1
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1answer
94 views

Replacing multiple polygon features by their shared center point in GRASS GIS

I have three polygon features of the same category in a larger vector layer from which I would like to create a center point (mean coordinate) that holds the same attributes as the three polygons. I ...
0
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0answers
18 views

Identifying Optimal Site Locations with Variables Weighted By Level of Importance

I'm using QGIS 3.4. I have a point shapefile representing population density, and I have used the "K means" vector tool to identify the 12 most optimal locations for service centers that would serve ...
0
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1answer
78 views

How do I get Table from Vector layers for use with joinattributestable

I am attempting to run: processing.runandload('qgis:joinattributestable', layer1, layer2, 'id', 'id', None) To join my tables and output to a temporary viewing layer. layer1 and layer2 are both ...
2
votes
2answers
1k views

Convert point to line

I recently completed a long bike trip and used a GPS to gather data during the ride, including average speed and elevation loss/gain. I imported the data into QGIS. These data were gathered per mile, ...
1
vote
1answer
21 views

Intersection of raster and vector - road file and maps (tif)

ArcGIS Desktop 10.6.1 I have a railroad vector layer (with 10 rows, that is 10 segments) and 30 USGS historic maps (tif files) that cover that route. I'd like to find the intersection, such that one ...
1
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1answer
748 views

Problem or ERROR in converting from raster to vector!

I wonder if anyone could help me out, i am kind of a beginner at QGIS. I´ve built a DEM for a project that i am developing than i´ve made the slope raster with the terrain analysis,it seemed that ...
13
votes
3answers
11k views

Calculating roundness/compactness of polygon?

I am trying to find ways to quantitatively describe the shapes of various polygons. For my project, these polygons represent lakes, rivers, lagoons, and parks. So they can be almost any shape. One ...
1
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2answers
360 views

How to convert vector format (geopackage, shapefile) to raster format (geotiff) using rasterio without template raster

I'm looking to create a raster given just a geopackage (or shapefile, or other vector format). I don't have a template raster, and all I wish to do is burn the shapes into a raster using rasterio. ...
2
votes
1answer
41 views

Coordinates of an area on a raster in QGIS

I am new to GIS and I have to do the following: I have a GeoTIFF raster file of a map with some features like clouds and water bodies. It is a satellite image. My images are taken from a snapshot of ...
1
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0answers
32 views

QGIS: Polygonize error

Running the Polygonize tool in QGIS keeps generating the following error: Processing algorithm… Algorithm 'Polygonize (raster to vector)' starting… Input parameters: { 'BAND' : 1, '...
2
votes
3answers
4k views

Splitting raster in QGIS? without cliper

I have polygon grid layer and raster image whitch want to split with my grid layer to have 9 new raster layers. I was doing it like this guy but my QGIS stop working and shut down every time when I ...
2
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0answers
22 views

Query of line direction histogram plugin

I was wondering if anyone could explain how this plugin works I have had a play around with it and I do like how it visualizes how vectors are orientated. However I ran one and opened the CSV file ...
1
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0answers
147 views

Determining Affine Transformation Parameters? [duplicate]

I am trying to use the qgsAffine plugin to do the transformation but I have no idea in its usage. How to find the transformation parameters? I found some posts suggest using the OpenJump How to use ...
5
votes
2answers
2k views

Seeking QGIS affine equation?

I am at the mercy of a govt authority who have provided utility information in a cad format with a 0,0 origin and a nonsense grid. About a dozen files, the grid and origin are entirely arbitrary. To ...
1
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0answers
16 views

Calculating the distance of raster cells from a vector within a polygon using QGIS

I am quite new to QGIS and am trying to use QGIS 3.6 to create a raster layer of calculated values of the minimum distance of each cells within a polygon (orange) from a vector (the river channel in ...
2
votes
1answer
29 views

Store results including style in vector format for QGIS, ArcGIS [closed]

As I am wrapping up my project, I would like to make my results available for download. There are however many flavors to choose from and I was wondering what format is best. My criteria include: ...
1
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1answer
69 views

Automatic correction of many topological errors in shapefile?

I have a database with topological error. In particular I have an overlay of polygons. I would like to correct these errors. I thought to use an automatic procedure since I have a lot of errors. I ...
2
votes
0answers
21 views

How to delete a file after processing an algorithm in QGIS 2.18?

I am trying to delete an intermediate file ("Temp_merged.shp") after running the singleparts to multiparts algorithm in QGIS 2.18. import glob, os, processing path_to_shp = "C:/Temp/Tracks/" ...
3
votes
1answer
69 views

Merging all vector files within directory with QGIS?

I am unsuccessfully trying to merge all shapefiles in a given directory using QGIS 2.18. I do not want to navigate to the folder using QGIS GUI tools. Instead, I want my script to include all ...
2
votes
3answers
339 views

Extracting a small subset of an .sdc file

There are some line features in the form of an .sdc file. I do not need all the data in the file, just a very small subset of it. I understand that .sdc files are highly compressed, and my file is ...
1
vote
2answers
505 views

Converting Direction Of Travel OSM vectors from “system” to another?

I have a painful doubt according Direction of Travel (DOT) vectors in OSM data. I'm using ArcGIS10, and a OSM data shapefile. I have a OSM road layer, that has many "Both ways" vectors and many "One ...
3
votes
1answer
380 views

Aligning raster data to vector data in QGIS?

I'm in the midst of aligning century-old maps (of Paris) to vector data of the modern same: Qgis' Georeferencer tool works fine, but doing the entire city that way is a gargantuan task. Paris hasn't ...
2
votes
0answers
35 views

Vector map (rivers) to Raster. [ **ERROR 1: Wrong value for -outsize parameter.**]

I want to transform this vector map: To something like this I only tried to convert the vector map through Raster> Conversion> Rasterize But I get this Error: QGIS version: 3.6.3-Noosa QGIS code ...
1
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0answers
18 views

Can QGIS be used to calculate the up-slopes (total area draining to a specified point) of multiple separate points simultaneously?

I am trying to calculate the area draining to a point of 240 separate points using QGIS. At the moment I'm using the Saga - Upslope Area algorithm to individually work this out for each of the 240 ...
2
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0answers
44 views

Isolating main polyline using QGIS?

I am trying to convert a line shapefile with branches into just one polyline, actually deleting every other diramation. Imagine something like this: :________|__________|____|||______ into :...
21
votes
3answers
9k views

How to access feature classes in file geodatabases with Python and GDAL?

I am trying to access a vector dataset in a ESRI File Geodatabase using Python + GDAL. I have successfully compiled GDAL with the file geodatabase API. The FileGDB driver is working correctly since ...
1
vote
1answer
46 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 ...
0
votes
1answer
24 views

Keeping 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. ...
0
votes
1answer
161 views

How to make layer stacking in envi for landsat 8

I downloaded landsat image 8 and i made layer stacking for RGB layers in ENVI (Bands 4,3,2) to classify the land cover types. but the problem appeared when i conducted supervised classification. I ...
0
votes
0answers
29 views

Clipping by mask results in blank output

After clipping by mask in QGIS 3.6 the output file has been blank (empty). Raster file and vector mask file have the same projected CRS: USER:100029 - * Generated CRS (+proj=igh +a=6370997 +b=...
-3
votes
1answer
8k views

A easy way to create buffer in QGIS?

In the old version of QGIS creating buffer was relatively complicated task. Basically you had to save your layer as a new one with metric cylinder CRS in order to calculate distance correctly. If ...