Questions tagged [vector]

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

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13 views

Run a tool on subset of layer two points at a time pyQGIS

layer = iface.activeLayer() request = QgsFeatureRequest() request.setLimit(2) request.setFilterFids([1, 2]) for feature in layer.getFeatures(request): print([f for f in feature]) params = { '-g' ...
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11 views

Exporting vector XYZ tiles using pyqgis on QGIS 3.18+

I am trying to automate the exporting of vector tiles using PyQgis. Without automation, using the tool in the processing toolbox called Write vector tiles(XYZ) under the vector tile category, it ...
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9 views

Performing cluster analysis when separate clusters and point layer using ArcGIS Pro

I have a garbage patch layer (cluster) and a plastic accumulation points (point). The number of points are less compared to the spread of clusters. there are many extra clusters. I want to identify ...
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43 views

Making multiple points on single location all visible at once

I am having an issue with visibility of multiple symbols at the same location. The scenario is: I am an archaeologist, dealing with groups of objects all buried together at the same time ("hoards&...
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1answer
24 views

How to mark a stored vector layer as exported

Through PyQGIS using QgsVectorFileWriter.writeAsVectorFormat() we can store a vector layer as .gpkg, is great! However, once we close the project and reopen it again, the layer name is showed but ...
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18 views

Does the clipping function in QGIS clip the data relevent to each polygon?

I am looking to clip geographical areas with population data already inputted. My question is: Assume I clip a polygon containing 100 people in half, will the newly clipped polygon report there to be ...
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1answer
23 views

Splitting Vectors with Raster Layer

Does anyone know of a method to split vector data based on a corresponding raster layer. For example, I have a classification with two classes and have an overlaid vector layer as seen in the image ...
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2answers
65 views

Calculating the length of two shapefiles in QGIS

I created the yellow area as a shapefile by hand. Then I calculated the perimeter. I also created another shapefile (blue) manually and calculated the length, see image 1. The next step was to ...
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44 views

Single numbers for accuracy and resolution for vector and raster data?

This question is meant as a modelling question, not having to do with particular data formats. It was edited to better separate spatial accuracy and resolution (precision). In order to make the ...
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1answer
42 views

Perpendicular line creation is not working in QGIS

I run the transect tool with 90 degree required parameter to draw perpendicular lines from a line. I got the output but when I measured the angle it is not showing as 95 degree. What will be the error?...
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54 views

Selecting the transect lines which touches the divide of a polygon from the river line

I have a polygon and transect lines which passes inside the polygon. Here I want to select the lines which touch the drainage and divide. The transect lines split at the river intersection. Since ...
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19 views

v.net.steiner tool in QGIS not producing output

I have a shapefile of a network of points mostly on roads (a county shapefile from TIGER downloads). I want to find a minimal length tree along the road network that hits all points within 100m of the ...
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35 views

How do I automatically remove the lines across the midrib which a river doesn't overlap?

I have a river line, mid-rib and transect line I am trying to get a transect line by keeping mid-rib as the reference and I need to include only the transect lines that overlap the river. Just like ...
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Non-alignment of vector and raster layers in QGIS

I have a vector map layer, raster climate data and added a delimited text points layer. My problem is that the raster extent does not quite match the edge of the vector map, and as a result, some of ...
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37 views

Draw a centroid line through a line-like polygon feature?

I have all these line segments travelling between points: I want all the one close to each other to be merged into a single feature. So I dissolved them like so: Now I just want one line travelling ...
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23 views

Plotting points over raster pixel positions, rather than geographic coordinates in QGIS

I've been doing some image processing in OpenCV. I have a numpy array which has x1,y1 and x2,y2 coordinates as raster cell positions (so not spatially referenced). I need these coordinates marked off ...
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25 views

Zonal Statistics in QGIS 3.16

I have a NDVI raster file generate from Landsat-8 data and using the Identify Features tool I am able to observe the individual values per pixel. I also have a vector kml file breaking down a region ...
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41 views

Shape ID is lost after converting a shapefile into a raster in QGIS

Instead of a landclass having the value 1 (my previous shapefile ID), the raster classes have the below values after shapefile conversion. The above input values and gdal command was used ...
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1answer
59 views

Trying to write a script that re-projects vector datasets in a folder

I am new to Python and am struggling with my code specifically with my loops.The project is supposed to abide by these rules: Must re-project shapefile vector datasets in the folder to match the ...
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19 views

Using r.houghtransform [GRASS GIS]

I am trying to draw lines that run the length of rows in an orchard. I have a nice binary image that I produced from an optical image (see below). I need to delineate the crop rows with a simple ...
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29 views

Snap two point layers PostGIS based on a field

I'd like to know if it's possible to snap point to point automatically in QGIS, only when the two layers have the same attribute value in a field. For example, in the first pic they are far away and ...
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9 views

Export file _Google Earth Engine_Null parameter passed to FileFilter get user data function

When I export Vector Shapefile or Raster file from GEE and try to open it on another software (ERDAS/QGIS) I am given the following error Null parameter passed to FileFilter get user data function. ...
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18 views

QGIS - Drape (set Z value from raster) not working

I have a shapefile layer containing lines and a raster layer imported from a Geosoft GXF. I want to assign Z values to the nodes in the lines based on the intersected cells in the raster. So I used ...
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33 views

QGIS Add Vector Geometry to Polygon query

I have intersected a landcover map with 10km grid squares and then used the vector geometry tool (Add/ Export geometry) to calculate the area of each landcover feature within the grid square. In the ...
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1answer
40 views

Converting floating point raster to vector

I'm trying to convert a raster layer to vector but I'm really struggling. First it says that I have floating points rather than integers so I have I have seen you can use raster calculator to multiply ...
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31 views

How to extract the data from a GML file to a shapefile format? or select only few features from a large GML file?

I have a very big GML file on buildings in Denmark. (I could only download a 'whole country' in one file, so it is big as 17GB, no.of features over 1million). I only need a very few of them in a small ...
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1answer
52 views

Iterating through QgsFeatures in active layer and adding label using PyQGIS

I am trying to plot contours that are stored in a shapefile (linestrings) with labels that have their value. I know how to get the feature attribute I want in Python via: name = "MSLP" ...
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1answer
10 views

Is there a way to compute an Origin-Destination Matrix with multiple start point attributes?

[QGIS 3.16] I am looking to compute an origin-destination matrix. However, from the starting point layer, I need to have multiple attributes within the matrix, opposed to the 1 linking attribute. Is ...
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11 views

V3.16.3 vector menu doesn't work

Installed Linux Ubuntu version 3.16.3 and want to split a state parcels file (95 counties), but when I click on the Vector menu item nothing happens. Have used this feature successfully before in an ...
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35 views

Linking points within a specified tolerance

I have a set of points, and I want to build lines between pairs of points whenever their separating distance is within a specified tolerance. For example, 3 or 4 meters. Is there a way to do it in FME?...
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2answers
67 views

Joining (merge, union) non-overlapping vector polygons with QGIS

I look for a solution how I can join several polygons that do not overlap with each other and have no common sides, by creating a new polygon. That is, it should be an output polygon covering the &...
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1answer
29 views

Rasterizing polygons results in gaps that don't appear in the original polygons

I'm getting gaps when rasterizing polygons and was hoping to get an idea on the best solution. The first picture is the polygons and there doesn't appear to be any visible gaps on the edges of the ...
2
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1answer
47 views

Selecting and clipping layers within user defined area using PyQGIS

I am new to QGIS and am trying to write a script that will allow the user to define a region on the map (either polygon or freehand) and clip all displayed map layers within this region to the user-...
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14 views

QGIS: Arrow symbol from 4 raster layers (x y dir)

I have 5m raster layers which represent runoff velocity. They are in 4 separate layers; velocity, X-location, Y-location, and Direction. I want to create an arrow symbol with color according to ...
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1answer
62 views

Clipping Shapefile to Raster Extent using GDAL with Python

I am trying to clip a shapefile (containing multiple polygons) to a raster's extent. A similar question was asked as Clipping polygon precisely to raster (extent) using GDAL?, with an answer that I ...
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21 views

Warp vector WGS84 polygons to an orthorectified sub image

I'm using GDAL Python bindings (and gdal command line tools via subprocessing) and I'm having trouble warping WGS84 polygons to an orthorectified subimage. I'm fairly new to GIS, so please excuse any ...
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2answers
48 views

Getting names and numbers in specific vectors from a dataframe in a loop R

I have a huge DataFrame, in which I need to extract some information that generates filenames that I need to search in my working directory later, I also need the value in each cell of the pixel ...
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1answer
45 views

Is there some string-like format I can use that would encapsulate what is in a GIS file?

I'm running comparisons to find if there was a change in data. I'm using GeoTIFF and GPKG files (GeoTIFF will be compared to GeoTIFF and GPKG will be compared to GPKG). I have a database with ...
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2answers
74 views

Query a GDALDriverH or GDALDriver without a dataset to find out if it is raster or vector?

Is there any way to query a GDALDriverH (in C) or GDALDriver (in C++) to determine if it works for vector formats or raster formats (or with both, such as fGDB)? In my iOS app utilising GDAL 2.2, I am ...
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1answer
72 views

How do I use Join Attribute by nearest in this case, to avoid referencing an algorithm output in field calculator expression?

I have a model that I have built to automate the process of assessing wind hazard on forested edges. Currently I can run it successfully but: I have to run it once, create the Test layer, and then ...
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2answers
194 views

Lowering elevation of lake using QGIS

I am in QGIS. I have a raster layer of mountains and a lake. I have a vector layer (shapefile) of the lake. It sits nicely where it supposed to be over the raster level. I am going to convert this ...
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1answer
35 views

Is it possible to 'clip' two line layers in QGIS?

Specifically, I am looking to merge my bus route network into my wider road network. I only want to work with roads which lie on the bus network. Is this type of clipping possible? Joining the ...
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1answer
45 views

GeoServer (New Vector Data Source from PostGIS)

I have this error on GeoServer: Error creating data store, check the parameters. Error message: Unable to obtain connection: Cannot create PoolableConnectionFactory (The authentication type 10 is not ...
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0answers
25 views

ArcGIS Pro pixellates vector marker symbol when published as web feature layer

I've added multiple SVG images to a feature layer as custom symbols in ArcGIS Pro. While these show up exactly as expected in ArcGIS Pro, the same symbols appear pixellated once the feature layer is ...
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0answers
22 views

Is there a way to join specific features of 2 seperate line layers into 1 new layer?

Specifically, I am looking to put speed limits (which currently reside in my road network layer), into my bus route layer (which follows some of the same roads, but not all within the road network). ...
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1answer
58 views

Compare two shapefiles by location and attribute in QGIS

I am looking for a way to compare two shape layers automatically. We have two files that represent two different states of our project and thus contain similar data in the same format (e.g. both point ...
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81 views

ogr2ogr TopologyException invalid input geometry; ring self-intersection

I'm facing a problem when using osgeo/gdal:ubuntu-small-3.2.1 docker image and running these commands on the Natural Earth vector dataset: # Get and unzip the data # (inspired from https://github.com/...
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2answers
44 views

How do I add my .shp file as a Vector layer in QGIS?

I'm working in QGIS 3.12 and my university as given us zip files of "data" for each practical we do. I've unzipped it and followed steps of adding a vector layer and navigating to the right ...
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1answer
38 views

How to merge polygons from two different features without creating a hole in QGIS?

How is it possible to merge the yellow polygon with the blue polygon without creating a hole and keeping the big yellow polygon intact. Each time I try to delete the small yellow polygon, the whole ...
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1answer
35 views

Draw an envelope for only selected features in many/Batch layers in QGIS

I have about 1000 layers, I did select by attributes Batch files and select by one step features I need in all 1000 layers. Now I need to draw the envelope for those selected features in all 1000 ...

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