Questions tagged [vector]
A coordinate-based data model that represents geographic features as points, lines, and polygons.
1,879
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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 ...
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3
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Cutting Polygons in QGIS at a specific distance from a feature in another layer
I would like to be able to cut polygons such as the one below, in QGIS, at a set distance either side of a specified feature on another layer, in this case a footpath line from OS Mastermap.
In this ...
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Hashing functions for GIS data
I would like to take geometries from a vector dataset and reduce them to a hash. This hash would then be used to verify the integrity of that data and also identify identical geometries.
Do any ...
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Load and apply Style from Postgres in QGIS 3
I want to write a plugin in QGIS3 that changes the style of a vector layer. The styles to be loaded are saved in a postgres database in the table 'layer_styles'.
I read here or here , to use ...
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How to convert a vector boundary to a raster map?
I need to output a PNG file of a raster map overlayed with boundaries present in a vector map. The problem is, the r.out.png script only exports a raster map. My boundaries are in a vector format. ...
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Create interactive map with no server
I have managed to build a great web mapping application using tiles created from GeoWebCache and a custom gridset, but I now need to add an overlay to the base maps. The only interactivity I need is a ...
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OpenLayers, zoom to vector layer extent
It seems quite simple thing to me, but I get an error.
map declaration
map = new OpenLayers.Map('map_element', {...
projection : _projObj.mercator,
displayProjection : _projObj.wgs84
}
layer ...
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Splitting line at point positions using QGIS
I have a polyline and I have two points on the polyline.
I would like to know if there is a tool or script that I could use to split my original polyline into 3 polylines? (Starting point to point A, ...
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1
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Visualising most likely direction of migration given points with ages using R?
I have a question about how best to visualise the predicted direction of migration given a set of points with estimated ages.
Imagine I have a set of geo coordinates, representing communities. For ...
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Estimating resolution of vector data?
I got an old vector dataset with polygons covering a continent. The data was first published on paper at scale 1:5 000 000 and was later digitalized. I don't have the original data and no information ...
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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 ...
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Filtering in QGIS attribute table similar to dropdown in Excel
I have a large amount of point data that has so far been managed in an Excel list. In the future, these should be shown in QGIS.
To convince colleagues of this, I am looking for a way to make ...
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Dissolving polygon on QGIS
I have a grid of polygons as in the figure below;
I need to dissolve the polygons into a single feature. I used the Dissolve tool on QGIS without specifying any dissolve field. The QGIS result is ...
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Customizing Popups in Openlayers
Is it possible to customize the shape of popups in OpenLayers? For example, I am creating a pop-up using the following approach:
var popup = new OpenLayers.Popup.FramedCloud(
"popup",
...
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How to calculate orientation of line segments using open source GIS?
I'd like to calculate the orientation of line segments relative to north direction using open source tools. Which tools or functions would you recommend?
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How to convert a vector map to raster in Qgis?
I am creating a thematic map (vector data) with different classes. How to convert this vector map to a raster map, keeping the classification?
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How to identify and eliminate overlaying polygons in Quantum GIS?
I have a shapefile with polygons and now, not sure why, most of the polygons became duplicated and overlaid, i.e. when i click to selected one, i get two selected... How do i identify those polygons ...
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Select all polygons that are completely within a circular buffer
I made several buffers around some points. Now I want to select all polygons that are completely within this buffer. My problem is that I also get the polygons that are partially outside of the buffer....
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Programmable buffers using GDAL and python
Is there a way to programmatically generate buffer layers for vector layers using GDAL and python?
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WFS to Vector Tiles
Is there, by some miracle, an existing piece of software which is able to convert a (3rd party, GeoServer) WFS feed into vector tiles? In a utopian world, this would happen on the fly, but a download/...
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Comparing 2 vector files
I'm looking for a tool which compares two vector files (eg shapefiles). Eg 2 versions of a river network.
Quite a lot of the records are equal, but some are different. A possible output would be eg a ...
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How to get a list of adjacent lots to a road in ArcMAP and PostGIS/QGIS? [closed]
In the following map, I have:
A line / road layer
A parcel / lot layer
The Task:
Find and count the list of lots adjacent to the road with their types (parcel_type is a field in the parcel layer)
...
- 8,533
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Creating building shadows in QGIS?
Can anyone think of a simple way to create a polygon to represent building shadows?
I have a shapefile with height information for the buildings and I want to create a simple plan looking like the ...
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Changing layer symbology in QGIS 3 with QgsFeatureRendererV2
I am updating a QGIS Plugin from QGIS 2 to 3 and I am struggling with changing the layer symbology (a single symbol type for a line layer). I would like to have all lines in my layer to have the same ...
- 1,536
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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 ...
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Merge overlapping lines in ArcGIS
I have a polyline shapefile containing a number of lines, some of which overlap. By overlap, I mean that they follow exactly the same path for some of their route, but also have bits that are not ...
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Assigning CRS to shapefile when it doesn't have one, in R?
I think that by using readOGR to import a shapefile renders worthless to put proj4string to the script since if any coords are available in the shapefile, it will be transported through the readOGR.
...
- 1,246
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3
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Openlayers remove previously drawn polygon on starting to draw next one
Objective:
At any point of time there SHOULD only be zero/one polygon(s) on a vector layer with a polygon control. I need the previous polygon to be removed as soon as user starts drawing the first ...
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Combining information from raster and vector layers in QGIS?
in QGIS I have 1 raster-layer (elevation) and 1 vector-layer (administrative units).
Now I would like to be able to query one of the administrative units and see the mean and min/max of the elevation ...
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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 ...
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Replicating ogr2ogr operation with GDAL vector translate
Following a comment on Error using SQL statement in ogr2ogr with Python string formatter, I am trying to use gdal.VectorTranslate() instead of ogr2ogr, but I keep receiving an error.
Using Windows, ...
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Loading Vector Layer using python console in qgis
I am using qgis2.6 version and new to pyQGIS. I tried to load a vector file using python console in qgis. I don't know where I am wrong. The layer was not loaded and does not show any error too. Help ...
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Merging and joining two line feature classes while maintaining attributes from both using ArcGIS for Desktop?
I created an event layer using the MAKE ROUTE EVENT LAYER tool based on anticipated scheduled events. The road layer which is the base layer is intact.
What I would like to achieve is combine layer ...
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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 ...
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How to style a LineString feature to be red colored?
I try to add Features with LineString geometries in different colors to a ol.source.Vector.
I tried to do this with the following code:
var myFeature = new ol.Feature({
geometry : new ol.geom....
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Converting Shapefiles to Mapbox Vector Tiles
We are currently hosting OSM vector tiles on our mapping server (courtesy osm2vectortiles and tilesever-gl). Now I'm trying to convert our own shapefiles into the same Mapbox Vector Tile format so we ...
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How to load multiple vector layers into QGIS' map canvas using python scripting?
I am trying to write a standalone script in python to create a QGIS map canvas. The vector layers I am attempting to load are Shapefiles.
Currently, I am able to load each vector layer, add them to ...
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Create shapefile of raster outline using python
I want to create a single bounding shapefile polygon of valid pixels in raster data (GeoTIFF) using python.
I need something efficient as I need to do this for hundreds of rasters. I had thought of ...
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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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Free implementation of Polynomial Approximation with Exponential Kernel (PAEK) algorithm
I need a Free (i.e. Open Source) implementation of the Polynomial Approximation with Exponential Kernel (PAEK) algorithm, preferably in C, C++, Python, Julia or R.
The algorithm is one of the ...
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How to create a point along a line given distance
I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
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Calculating polygon length and width using open source GIS?
How can I calculate the length and with of polygons using open source tools?
By "polygon length" I mean the length of the longest line within the polygon (update: to be correct, I just need the ...
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GDAL/OGR Determine if dataset is raster or vector
I am writing a script using the GDAL/OGR Python bindings and it is possible that the user may provide a raster dataset or a vector dataset as input. If the user provides a vector dataset, the script ...
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Generate centroids for vector polygons based on raster and land-use data using QGIS
Although QGIS has the ability to generate centroids for polygons, I am not sure how to generate centroids based on land-use development using raster data.
Here's an example of what I'm trying to do:
...
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Finding largest number of observations within a given radius
I have the following problem: Given the location of insured properties (say houses with fire insurance), i have to find the largest sum of insured values which fit into a 300m radius. Now, my first ...
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How to use simplify()
i have my Vector Data saved in a PostgreSQL PostGIS enabled Database.
The Data im displaying is very detailed, i want to simplify it through the simplify() method of Postgis.
I duplicated one of my ...
shitake83
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1
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Writing compressed vector data for access in QGIS
I'm trying to find an optimum vector file format to be used to effectively store data (compressed binary?) and select subregions.
I have a quite large ascii point file containing 3 columns (x and y ...
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What is the fastest way to digitize features on a map?
I'm currently using QGIS basically to trace a bunch of polygons to show individual ponds from google maps. Some of the geometries can be pretty oddly shaped and using the nodal digitizing tool gets ...
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How to merge overlapping and duplicate lines from vector layer to one single line?
I used the "polygon to line" tool from QGIS, to get a line-layer from this polygon-layer:
Unfortunately this causes overlapping and duplicate lines, after I broke the qgis-export via GRASS into ...
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Loading a multipoint shapefile in R
This issue has only been raised in the community once, two years ago, to the best of my knowledge. I think it's high time to raise the issue again!
readOGR, from the rgdal package, cannot handle ...
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