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Questions tagged [vector]

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

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6
votes
1answer
1k views

How to emulate a specific vector grid in QGIS?

I would like to analyze data included in a pdf file. The file contains information on characteristics of 16km grid cells for a specific study area. The file also includes a map displaying the grid. I ...
5
votes
1answer
8k views

Shapefile/vector layer not appearing in QGIS

I have a shapefile (calling it 'new.shp' for discussion's sake) that won't show up with other layers. If a fresh file is started and I bring in new.shp, it will appear, but any other layers imported ...
5
votes
8answers
2k views

Any Good Map Rendering Engines for SqlGeometry/SqlGeography

Can anyone suggest good map rendering engines for MS SQL Server Spatial types (SqlGeometry/SqlGeography)? By rendering, I mean plot the geometries to a common image format such as png or jpeg with ...
5
votes
1answer
3k views

Getting result in metric from QGIS Distance Matrix tool in QGIS? [closed]

I'm trying to calculate the distance between points in layer with distance matrix tool. And keep getting strange results no matter what. Like this MASTER ------------SLAVE ---------------- DISTANCE ...
5
votes
1answer
5k views

Change vector projection in Openlayers

I have added vector layer to map: vactorTest = new OpenLayers.Layer.Vector("Editable Features", { strategies: [new OpenLayers.Strategy.BBOX(), saveStrategy], projection: new OpenLayers.Projection(...
5
votes
1answer
444 views

LiDAR Feature extraction specifications/standards

I have vector data representing forests/trees/buildings that have been automatically extracted from LiDAR data. I am looking for specification/guidance for LiDAR derived products, or any standard for ...
5
votes
2answers
957 views

Distribute points respect to features using Quantum Gis

I want to know if there is any tool to make points with respect to selected features in a theme? Using: vector, investigating tools, regular points you can do it but not with respect to a selected ...
5
votes
3answers
1k views

How to measure the distance of multiple points to a line

I have two shapefiles in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to ...
4
votes
0answers
793 views

How to perform spatial join and obtain attribute in python/GDAL?

I am working on a script that will take an unprojected raster, and using a UTM grid (shapefile), will obtain the correct SRS (I have a shapefile where each zone is attributed with its numerical SRS) ...
4
votes
3answers
441 views

qgis:mergevectorlayers won't allow two layers for the second arg

I've been searching the web with no luck. This old exchange should be exactly what I need: Merging vector layers via python in QGIS 2.18.1 My code looks like this: processing.tools.general.runalg("...
4
votes
3answers
860 views

ogr2ogr equivalent of QGIS Union

I have two polygon vector layers one of which has more than 100,000 polygons. There are areas of overlap in the two vector layers however they have different attributes. In the final layer I want the ...
4
votes
2answers
1k views

How to get the command line of QGIS algorithm “Merge vector layers”?

To insert this function to my program I want to know what is command line executed by the algorithm "Merge vector layers" using QGIS GUI.
3
votes
0answers
222 views

Regridding vector values

I'm trying to regrid and interpolate vector values from WAM model output. I got WAM model netCDF output in rotated grid, I need to interpolate it to another grid which is some variant of LAEA ...
3
votes
1answer
2k views

Vector menu tools missing (processing plugin broken)

All of a sudden my vector menu tools are missing. I know this is a common bug but all the instructions on how to fix it didn't work for me. I checked if the processing plugin is installed but QGIS ...
3
votes
1answer
703 views

Merging two adjacent polygons which borders are not touching each other?

I want to merge adjacent single polygons which are apart from each other. Important note: I cannot use ArcGIS, I need to do this programatically, in any language (R, Python, Ruby, PostGIS) doesn't ...
3
votes
2answers
356 views

Why does GDAL open a DTED file as a vector format?

GDAL version: 2.1.1 Language: C++ Given the path of a geospatial file, I want to know whether the file is a raster or vector format. The only way I have found so far to make that distinction is to ...
3
votes
1answer
44 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 ...
3
votes
2answers
2k views

Convert Raster to vector - create polygons based on each pixel

I want to convert a raster file (100x100m pixel size) which contains population counts as pixel values. I need a vector based file of the 100x100m grids and the population as attributes. I tried ...
3
votes
1answer
249 views

Batch distance calculation with v.net.distance

I have three shapefiles: one containing destinations the second containing postcodes the third containing the road network I want to calculate the distance between the postcodes and destinations ...
3
votes
1answer
2k views

Why is the Vector menu missing upon installation of QGIS 3.0?

Why is the Vector menu missing upon installation of QGIS 3.0? Others mentioned that some of the tools were missing from the menu when they installed a previous version, but in my case the entire ...
3
votes
1answer
2k views

How to invert polygons (or other options for exterior styling)?

I have a shapefile containing many polygons that I want to use to mask a raster. I have tried gdalwarp -cutline <shapefile> -crop_to_cutline -srcnodata -9999 -dstnodata -9999 <source_raster&...
3
votes
2answers
3k views

Identify polygon containing point with R sf package

I would like to be able to map geocoded coordinates to a region on a .shp file in R using the sf package. I can load up the map and plot it but I am struggling with the code to return the region for ...
3
votes
1answer
1k views

How to ‘invert’ or ‘reverse’ a vector cutline when gdalwarp'ing a raster?

I have a raster of North America and I'd like to remove the larger lakes from it, replacing them with the same no-data value as the original raster. So I downloaded Natural Earth's 10 meter lakes ...
3
votes
1answer
475 views

How do I fill a combobox in QGIS with only points vector layers?

I'm new to writing plugins in python for QGIS. I've been searching on internet for a while and wrote the code below. Even though it fills my combobox, all layers (rasters, vectors of all geometry ...
3
votes
1answer
6k views

How to get attributes of overlaying polygon layers by a spatial query?

I am new to QGIS and would like to merge selected data/attributes out of the attribute tables from overlaying vector objects on different vector layers without creating new additional layers. Is ...
2
votes
1answer
424 views

QGIS Script - VectorWriter error

I am running a QGIS network script called "Transit-tools-QGIS" on QGIS 2.12.3 I am interested in this script for my network: https://github.com/chourmo/QGIS-Transit-tools/blob/master/scripts/...
2
votes
2answers
1k views

Merging vector (building) elevations into DEM in QGIS?

I'm no expert in QGIS, I'm more into engineering. I'm building a 2D hydraulic model and I would like to add the building footprints (elevated) to my DEM, so flow will go around structures in the ...
2
votes
1answer
359 views

Loading a Shapefile in standalone PyQGIS script

I am writing a script to validate a shapefile. Here my code: #-*- coding: UTF-8 -*- import os from osgeo import ogr from PyQt4.QtGui import * from qgis.core import * import sys app = QApplication([...
2
votes
3answers
1k views

Cut many lines with many polygons: Too much for my CPU/RAM?

I have a line-shp (80mb) and a polygon-shp (5mb) and want to intersect them. In result, the lines (contours) should be cut by the polygons. After using one of the tools "Vector -> Geoprocessing -&...
2
votes
1answer
494 views

Line to polygon conversion

Currently we are working in a geological project..in which all the Contacts, Linear & some other geological features have to be captured. The thing is most of the features have to be Captured as ...
2
votes
1answer
299 views

Combining DEM file with building (height) vector files using ArcGIS Desktop?

I am using ArcMap 10.2. I need a DSM file to use for my thesis to run visibility analysis on it, but my case study (Tehran) do not have LiDAR data. So I am thinking to combine a DEM file with ...
2
votes
1answer
2k views

Openlayers 3 Circle Vectors Not Visible

I have two coordinates which are projected in EPSG: 3857 coord1 = [-10399758.486973494, 5604341.818491254] coord2 = [-10402629.416641055, 5593700.936383396] I'm trying to get them to appear, ...
2
votes
0answers
58 views

How to export a single feature (line) from multiple layers and export to individual layers?

I have multiple vector layers representing a time series. Each layer contains many lines each. I want to select a single specific line from each of these these layers and save it to another layer. ...
2
votes
1answer
3k views

How to edit a vector layer extent?

I'm working on QGIS 2.2, and I would like to make a vector layer extent bigger (thus the clip option is not suitable) to match exactly my mask layer extent. I would like the new added area to be empty....
2
votes
0answers
76 views

QGIS rasterize a styled layer [closed]

I disabled information from a vector layer with a styledefinition. Is it possible to rasterize only the styled information in QGIS?
2
votes
1answer
669 views

Why are layers not lining up with others with the same CRS? [closed]

I am creating a project on the UK and have downloaded various shapefiles. When I add a vector layer they are coming up as if they are not lining up. Some layers are nicely on top of each other with ...
2
votes
1answer
554 views

How to add a band with conditional value to a raster with PostGIS

I'm trying to convert a vector polygon into a raster, with pixel values that indicate the area of the intersection. I have a query that gets the area of intersection between an empty raster and the ...
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
votes
1answer
957 views

Why does intersect not calculate polygon areas?

this is strange: I intersected 2 shape-files and the resulting shape does not contain the Shape_Area and Shape_Length of the intersected polygons. Instead the field Shape_Area contains the polygon-...
2
votes
2answers
4k views

How to set cell size for vector to raster conversion in QGIS GRASS plugin?

I'm converting a vector (loaded in GRASS plugin in QGIS (1.7.0.-wroclaw) and would like to convert this to a raster with a defined cell size. At the same time I need a value from the attribute tabel ...
2
votes
2answers
760 views

Split Vector Points/Polygons by Vector Grid and assign to relevant grid

I have 3 vector shapefiles (1: Point, 2: polygon, 3: vector grid) that I would like to combine so that the points and polygons are 'assigned' to the relevant grid cell within which they are contained, ...
1
vote
2answers
1k views

Clipping shapefile with Python?

My problem is the following, I cannot find a reasonable method to clip 2 vector based shapefiles using python (without ArcPy or QGIS API). I tried using the geometry.intersections method, but that ...
1
vote
1answer
1k views

Clipping raster with an irregular shape?

How can I clip my DEM raster in a irregular shape in QGIS? I have used the clipping tool but it only does rectangles I believe.
1
vote
1answer
54 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 ...
1
vote
3answers
135 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 ...
1
vote
1answer
1k views

How to select a raster file that is under a polygon in a vector file?

I am using: v.db.select map=PHL_adm1 where=NAME_1='Bulacan' My vector map is over the raster map. I want to select the part of the raster map under the polygon(NAME_1='Bulacan') of a vector. Is it ...
1
vote
1answer
268 views

QGIS batch affine transformations

I have multiple polygon and line shapefiles on which I would like to apply a translation so I was wondering if it is possible to batch process them (maybe with graphic modeler ?) or do I have to ...
1
vote
2answers
575 views

Mapping continuous vector data on a continuous colour gradient in ArcMAP 10

I'm plotting vector data for different attributes for countries across Europe. I've used symbology to plot categories of countries. However, the data are numbers so are on a continuous scale. I would ...
1
vote
0answers
329 views

How to create contours from an IDW raster

I'm new to QGIS and am trying to create vector contours from this IDW raster. I followed Ujaval Gandhi's "Interpolating Point Data" tutorial step by step but am not getting the same results for step ...
1
vote
2answers
159 views

check the “quality” for (poly-)lines (density of vertices)

I want to check the quality of digitized tracks. I suppose, that a track with a lot of regular vertices has got a good quality. And a track with less regular vertices has got a poor quality. Maybe, I ...