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Questions tagged [vector]

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

1
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3answers
4k views

Convert MultiLineString to LineString using QGIS

In QGIS, I've tried the following options to convert my GeoJSON file from MultiLineString to one or multiple LineStrings (translating the Danish version): Vector -> Geometry Tools -> Polygons to ...
1
vote
1answer
169 views

dxf rotation and georeference [duplicate]

I have a DXF (layout) which is to be spatially adjusted to a point shapefile that has correct X Y cords. When I add both as vector layers to Qgis, point shapefile is right on place but dxf shows a ...
1
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1answer
663 views

Calculate if day/night time for point dataset [closed]

I have a point dataset (crime data for Stockholm) with timestamps and I want to calculate for each point if the certain crime happened during day or night time. So connecting the timestamp to sunrise ...
4
votes
1answer
224 views

interpolate raster values to the extent of a bigger vector layer in QGIS 2.18.16

I have raster data (1km resolution) of nationwide multiannual precipitation. Unfortunately, the raster layer does not completely cover the extent of an underlying vector layer (see picture below). I ...
2
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0answers
122 views

Issues with geometry in QGIS but not ArcGIS? [closed]

I have found that shapefiles that function normally in ArcGIS will not work in QGIS due to geometry issues. For example, I have a species geographic range file that when I intersect with a buffer will ...
1
vote
2answers
130 views

reduce nodes in polygons

I have a shapefile with several contiguous polygons and I want to reduce their number of nodes. I was thinking of deleting nodes based on the angle that results from the 2 segments on either side of ...
1
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1answer
73 views

Transfer attribute and split line

I have two line dataset that represent the same roads: First one has very precise geometry Second one has an approximative geometry, but very interesting attribute. What I want to achieve is to have ...
0
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2answers
532 views

Getting feature coordinates from dynamically loaded layer using OpenLayers?

i want to load the coordinates of a point that is stored inside a vector layer and the vector layer is stored inside a layergroup. I do load the vector layers dynamically to the layergroup "Runs". So ...
0
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1answer
72 views

Administrative country boundaries over the years

I am using natural earth's Admin 0 Countries dataset and it works great, but need to plot some data going back to 1962. Any idea how I could handle the national border changes? (In fact, I only need ...
1
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1answer
149 views

QGIS Contour WAsP .map output file format

I want to create WAsP .map vector file in QGIS from a input ascii file. For this, I tried using Raster->Extraction->Contour and then set the option for 'Output file for Contour lines (vector)...
4
votes
1answer
3k views

Get feature from ol.interaction.Draw on drawend

My problem seems simple but I cannot find any questions that successfully solve it. I want to draw a circle using ol.interaction.Draw, and access the feature that is created immediately. My code as ...
2
votes
1answer
480 views

qgis-bin-exe-stopped-working No Shapefiles allowed

I'm using Windows 7 and I'm having the problem of QGIS 2.18.16 crashing with any shapefile. Rasters seem to be OK. I have tried uninstalling and reinstalling 2.18.15, 2.18.14 and one older version (2....
2
votes
2answers
2k views

Converting raster tif to point shapefile using Python?

I've been working on a data that is in .tif raster format. I need to convert that into a points shapefile (.shp) to proceed. I went through GDAL in Python but there's only gdal.Polygonize(). So how do ...
2
votes
1answer
130 views

Reprojection problem WGS 84 / UTM zone 21S - EPSG:32721

I'm working on a EPSG:32721 project that works just fine. I'm trying to add a new vector to this project, but I just can't find the way to align it with my others layers. What is very strange is ...
1
vote
1answer
81 views

Saving output from vector-tools as temporary file or straight into input layer?

In mapinfo it is possible to save an output without creating new shp. Either by saving into the input- layer or to a temporary file. For example if you want to ”union” two layers you may want to get ...
1
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1answer
312 views

QGIS: How to create a permanent vector layer

I am currently creating an vector layer like following: outLayer = QgsVectorLayer('Linestring?crs='+ crs, 'graph_with_azimuth_ogr' , 'memory') The outLayer is now stored in memory, which means it ...
3
votes
1answer
81 views

Split a vector into parallel grids [duplicate]

I have a piece of land (vector) with, for example, potatoes and I want to make a grid for spraying. That means i need a grid with size 45mx10m with different values per box. Important is that the grid ...
7
votes
1answer
839 views

Different layer styles at different scales in QGIS?

I would like to be able to show a basic style for a layer at a large scale, e.g. GB-wide, with all polygons the same, but for this to change at a smaller scale, e.g. 1:25K, to differentiate between ...
0
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1answer
144 views

Programmatically styling MapInfo Table without MapBasic?

I'm doing some research into how I can convert a GML file to MapInfo TAB and then style it using the same script. I have read about a column called MI_STYLE, however my understanding of this is that ...
2
votes
0answers
54 views

How to sum attributes from different vector grids?

I am using QGIS and have a vector grid covering part of South Europe. The grid is made of rectangles each with equal size 0.01 degree. So there are thousands of features defined by four values : left, ...
5
votes
1answer
936 views

QGIS Calculate angle between two lines

I am currently trying to calculate the angle between two lines or rather vectors (which are not touching) like in the picture shown below: In order to calculate the angle α, I think I will have to ...
1
vote
2answers
1k views

Converting from ECEF to geodetic coordinates

I am trying to convert an ECEF coordinate to a geodetic coordinate using this procedure, but I don't fully understand the process. It is prefaced by stating the geodetic parameters {a,b,e,e'} are ...
2
votes
1answer
49 views

Attributing stream segments based upon road intersections and stream confluences

I am currently working on attributing nodes along some stream polylines. The attribution is supposed to include: 1)length of the stream from it's reference point 2) the location of the node in ...
4
votes
1answer
307 views

Vector Tiles for NetCDF Data [closed]

I understand that the GeoServer can produce vector tiles in three formats: GeoJSON, TopoJSON, and MapBox Vector (MVT). Moreover vector tiles has many advantages in handling data such as reduced size ...
1
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0answers
38 views

Save Vector Layers in Group [duplicate]

I have a list of shapefiles stored in a group: pump I want to save all shapefiles as a new shapefile with a new CRS. For that, I wrote the following script: import os as os from qgis.core import * ...
0
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3answers
173 views

Vector lines as blockage for viewshed analysis in QGIS

I have a SRTM elevation model with a point from which I would like to calculate the aproximate visibility. Using the line-of-sight tool in QGIs, I can achieve that without any difficulty. However, I'd ...
3
votes
1answer
204 views

Checking if vector coordinates are inside raster file using pyqgis?

I have some tifs files inside a folder and want to check if a shape coordinates are inside one of the tifs with pyqgis. I tried this from Determining coordinates of corners of raster layer using ...
3
votes
1answer
356 views

Adding vector layer to QGIS?

I am learning QGIS from scratch. Downloaded the software and data. I am following their manual uploaded in PDF format. I am stuck in the first step to add the vector layer. The layers panel show a ...
1
vote
1answer
38 views

Data gets skewed when re-adding it into the table of contents

some of my data gets re-align every time i re-add it in within the QGIS Table of contents ( like a good 5-10 feet off). I have no idea what could be the cause, I may have the given layer in a ...
2
votes
1answer
40 views

When computing distances between 2 vector layers - getting window of analysis right size

In QGIS I have a big island (Britain). There are lots of rivers inland, but not many at the coasts. The rivers were originally vector layers. I converted them to Raster (by burning them with the value ...
1
vote
0answers
45 views

Road Network Accessibility

I am working in qgis with 3 layers: one is road network and other is hospitals and locations of accidents , later two layers are as points, I want to figure out what accident location (points ) are ...
0
votes
1answer
96 views

Why does Q-Chainage sometimes offer meters and sometimes degrees?

Q chainage is a plugin which puts regular points on a line vector at regular intervals which you can specify. For a shapefile I've been given (and converted to line vector), it offers me to specify ...
1
vote
2answers
265 views

Points and polygons difference issue QGIS

I'm trying to remove points that are in polygons with the basic difference tool (Vector-> Difference). What I see after the operation suits me because all points in polygons are deleted, but as I ...
1
vote
1answer
81 views

Q-Chainage plugin. Chain points layer does not save properly

Using Windows 10, QGIS latest version. Use Q chainage (vector plugin) to make a chain of points on a boundary (line vector layer). I save the points layer (as layer definition file), and also save the ...
1
vote
3answers
1k views

Qgis is not exporting vector PDF at larger scales

Context We're now in the process of transferring our systems to Qgis. what needs to be done I need to export a DXF based map from Qgis into vector pdfs, in order to import into the program we use ...
2
votes
0answers
193 views

producing smooth iso polygons from raster surface? [closed]

The objective is to turn a raster surface (double value type) into smooth, visually appealing polygons representing iso-levels. I cannot stress enough that these must be visually attractive. Jaggedy ...
0
votes
1answer
68 views

Creating coverage file (vector) from raster data and indexing it to original files? [duplicate]

I have a large number of LiDAR files (in .asc format) that I'm wanting to catalogue so it is easier for people to find the files they want. How can I take LiDAR files I have, and create a .shp file (...
0
votes
1answer
52 views

Merging/Compressing attributes in a single vector shapefile QGIS

Using QGIS v 2.18.10 I'm currently working with a vector shapefile that represents zones in a municipality. I've had to create and edit polygons representing these zones. I'm looking to compress/...
1
vote
0answers
49 views

Raster to vector, matching another vector in QGIS?

I have taken a pdf of a map and managed to import it into my map using the QGIS geolocator. Now I want to convert the resulting raster layer to a set of polygons that match up with the existing vector ...
2
votes
1answer
294 views

QGIS saving raster styles as vectors

I am using QGIS for analysis of aerial images. I have used the properties>style menu to create colour-banding for my raster map layer. This created 2 colour bands - but I want to convert these to ...
1
vote
0answers
47 views

How to create least-cost path with PyQGIS that penalizes sharp edges and uses each line only once?

I would like to connect user-selected nodes via a line layer, in which each segment has a certain cost value. The lines should be connected via the least-cost path. So far, I am using the module ...
2
votes
1answer
163 views

Use temporary vector layer in scripts

I would like to create a vector layer, add a point to it and then use it in qgis algorithms. This is what I wrote : #create temporary layer containing center point point=QgsFeature() point....
3
votes
1answer
155 views

QGIS Densify Geometries based on expression

I tried using the Expression Based Input in the Densify Geometries tool with the following expression: attribute( $currentfeature ,'VertNum') where VertNum is a field in the attribute table that ...
3
votes
1answer
361 views

Interpolate (TIN) within a polygon extent QGIS/GRASS

I am trying to interpolate (TIN) in QGIS to produce surface models. I need to interpolate within a polygon area extent. The options available in QGIS do not allow this as far as I am aware. Is there ...
2
votes
1answer
111 views

Adding and saving layers from QGIS console

I have a data-set of .tif satellite images and .geoJSON labels corresponding to them. I am trying to iterate over the satellite images,plot the geoJSON labels and save them as .jpeg images. However,...
4
votes
1answer
161 views

Summing attributes of different shapes into another (height of contours + height of buildings)

I'm using QGIS 2.18. I need to calculate the height of the rooftop of each building in a neighborhood. I have a vector shape of the buildings, with the building height attribute (from the ground to ...
4
votes
2answers
557 views

Create contour line from point table in PostGIS

I have a point table containing values ranging from 0 to 100 and I would like to draw a contour line for the value 70. (See image below) I know how to create contour lines in QGIS for raster data but ...
4
votes
0answers
154 views

QGIS 2.18.14 vector Clip analysis producing erroneous result

I am trying to perform a vector clip analysis (vector-->geoprocessing tools pull-down menu) using two complicated vector layers and am getting erroneous results. The clip 'Input layer' is shown here: ...
0
votes
1answer
302 views

spatial filtering data in R between two vectors

I have two shapefiles in R. One contains a vector of coastline (called coastline) and the other file of parcels (called parcels). I want to filter the parcel data for only those parcels within 1 mile ...
3
votes
1answer
2k views

Split a vector layer based on attribute value?

I have read the question and comments on: Splitting shapefile into separate files for each feature using QGIS/GDAL/SAGA? that can be seen here: Splitting shapefile into separate files for each ...