Questions tagged [vector]
A coordinate-based data model that represents geographic features as points, lines, and polygons.
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When moving a feature in QGIS, is there a way to nudge it rather than use the mouse?
I need to move a lot of features (polygons) in QGIS to fit a newly Georeferenced scanned map that is slightly asymmetrically distorted. This is fine as it is just to provide a print copy.
I end up ...
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QGIS Vector Toolbar Has No Tools
I am trying to use the Table Manager to rename a field in an attribute table. However, the Vector Toolbar in my install of QGIS 2.14.0-Essen 64-bit Windows shows a toolbar with no tools in it. The ...
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OpenLayers - Get features inside a polygon
In my OpenLayers map I allow users to draw an ad-hoc polygon vector. Then I need to get all the features from a WFS vector layer that fall within the ad-hoc polygon.
Here is the code I have that ...
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Creating raster from point values
I have a raster whose pixel values are 0 or 1 (b/w areas in the image below) and data type is Float32.
I made a point layer from each individual pixel's center. Then I made some calculation for all ...
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OpenLayers how to maintain layer ordering while using SelectFeature control
I'd like my map to display a few layers in a particular order. Some of these layers are Vectors, others are XYZs, and some of my Vector layers display attribution.
Initial layer ordering works fine ...
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How to remove long linear strips from polygons?
I have a polygon layer representing impervious land cover. This was taken from a land cover raster dataset. The impervious data represents all impervious surface that is not buildings or roads. I ...
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Checking if polygon fits inside another polygon using ArcGIS Desktop?
How do I check if one polygon fits inside another polygon? Furthermore how do I automatically check if one polygon fits in other polygons of my shapefile?
I have a shapefile with thousands of ...
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How to determine optimal windmill placement to maximize production?
How can I add automatically the maximum number of points (dots) with 6m diameter and 100m distance each point from other into an area. The dots will present the windmill base (6m) and I want the ...
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Calculating buffer distance for different groups of parallel lines in QGIS
I have a number of parallel lines (see here for the background: How to extend lines to Bounding Box in QGIS?). My final aim is to create the Centerline for each group of lines as illustrated here:
...
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How to clear attribute columns from a Shapefile?
I want to clear all columns from a SHP. Only need geometry of features. I use QGIS and Sextante with grass and saga. Is there any tool for this job...
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Spatial query of raster data using QGIS
I have population distribution data as a raster layer and exposure contours as vector (polygon) layers. What I'd like to do is use the vector layer to estimate the population indicated from the raster ...
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Seeking European City boundary data?
Does anyone know any sources for free European city boundary data?
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Converting points to lines with Python GDAL
I have a dictionary with points. The points are derived from a raster (see image below). The points are not sorted and are not in order. The dictionary looks for example like this:
pointDict = {0: (...
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Does an openlayers vector layer work across browsers?
I was under the impression that it was.
Here is my example:
<html lang='en'>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>GeoRSS</...
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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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Showing nested polygons in QGIS?
I am working with QGIS and in particular with river basins.
If you see my picture below, each label shows a particular basin but actually only the biggest is shown (because I think its area covers ...
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How/Where can I find vector data for building footprints in Texas?
I've done a lot of research on this topic over the past 8 or 9 months, but I'm a GIS newb, so I may have overlooked some possibilities for finding/extracting this data.
A short list of resources I ...
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Merging layers of certain geometry type only in QGIS
I have nearly a thousand layers of geospatial data consisting only of Point layers and Line Layers and I just want to make it so that I only have one layer for each type.
Is there a way to filter to ...
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Splitting vector layer in R
Is there a way to replicate the Split Vector Layer function from QGIS in R?
I have a Shapefile containing around 20 polygons that I'd like to split into 20 separate files.
I guess since it's in ...
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Splitting polygon using another polygon in QGIS?
I have two polygon layers (yellow and orange in the attached image).
I am wondering if there is a way to get a count of the number of isolated areas that the orange polygon has divided the yellow ...
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Finding format/type of the vector geometry
Does anybody know what format is the following element?
01000000804AE9B78F8F0D416258AE25F8E45141
It looks like WKB or PostGIS geometry/geography but I didn't manage to convert it.
It has to be point ...
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How to edit an existing layer using leaflet?
I am used to working
with OL3 and I wanted to try using leaflet and see if it is as powerful as OL. I loaded a map with some data from a GeoServer WFS layer using this tutorial from Georepublic.
var ...
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Automatically updating user-edited features in QGIS plugin
I am working on a plugin for QGIS (2.12). It uses data stored in an Spatialite database. When the user creates a new feature, the plugin should:
update the feature attribute table (the popup form ...
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Splitting lines at a specified distance
Does exist some plugin with it is possible to Splitting lines at a specified distance in Qgis?
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Checking whether layer is vector or not in OpenLayers 2?
How do I dynamically check whether a layer object belongs to the OpenLayers.Layer.Vector class?
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Calculating proportional area of polygon covered by circle [closed]
I have two layers here (ignore the green layer), blue polygons and black circles. I want to calculate for each circle, what percent of the each of the blue polygons does it cover. For example, the ...
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Vector layer does not appear with OpenLayers
When I import the vector it simply does not show in the map. I tried with a raster and it worked fine. I tried now with both KML and GeoJSON and the same thing happen, I can see that it loaded in the ...
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Calculating average raster to point distances within census tracts
I have some experience using ArcGIS, but mostly with the field calculator in the attribute table/spatial joins, so I apologize if I say something that doesn't make sense.
To provide a bit of ...
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Creating new vector layer that fills space between other polygons in QGIS
I inherited a clipped (500m radius) land cover map containing vector layers of different land cover categories such as buildings, grass, roads, etc from a colleague.
The empty (white) space in the ...
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Fast data representation on the vector layers
I have found an interesting article about how HTML5 supports representation on large datasets.
Article can be found here. In the article it is said that HTML5 and feature simplification can ...
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fTools-Error: "...invalid geometry..."
I want to intersect contours with polygon like in the image below. But I got this error:
Warnings:
GEOS geoprocessing error: One or more input features have invalid geometry.
Some output geometries ...
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Restricting the creation of lines for network creation in QGIS: start/end vertices must snap to existing vertices
My interest lies in network creation, however, knowing how to do that in general would be a plus. How is it possible to prevent a user from creating a line (line vector) without connecting it ...
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Representing overlapping polylines in QGIS
I have several shapefiles representing bus lines with different colors for each segment, however, because the lines are exactly superposed, only the shapefile on top can be seen. Is there a way to ...
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LiDAR returns over water bodies?
I have obtained LiDAR data from my environmental agency in order to obtain the relative heights of each watercourse station. A far as I know, LiDAR signals do not get returned over water bodies. ...
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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 ...
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Zonal statistics per raster category in QGIS?
I have a raster layer of land use and a vector layer of areas of interest.
I would like to calculate for each polygon (areas of interest) the proportion or number of cells of the raster, for each ...
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How to compare two sets of points in QGIS?
I have two point layers with XYZ data; one set are points measured in the field and the second set is a Lidar data set.
I want to check the accuracy of the Lidar in comparison to the measured data.
...
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QGIS to Illustrator: file cannot be opened because there is not enough RAM
I am having trouble getting my files to transfer or export to a vector file. When I open the file in Adobe illustrator there is a lot of information missing. I have tried to "save selection as a ...
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Sketch event in Openlayers 3 drawing interaction
For drawing Polygon in OpenLayers 2 we could use as follow:
function drawEnd(){
...
}
function putPoint(){
...
}
function sketchModified(){
...
}
function cancel(){
...
}
var ...
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OpenLayers Only draw features in a vector layer within view
I am dealing with a kml that I am importing into openlayers as a vector layer. This kml has many features so it dramatically slows down the web app. I would like to make it so only the features within ...
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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 ...
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How to use FactoQGIS for Typological Analysis Principal Components Analysis (PCA) for vector features in QGIS?
How to use FactoQGIS for Typological Analysis Principal Components Analysis (PCA) for vector features in QGIS?
I have a shapefile of polygons as in the following image:
Both visually and as ...
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Batch create multiple buffers with variable size around point
For a statistical analysis, I need to calculate some landscape properties in several (rectangular) sample areas, which vary in size (extent ranging from 10 by 10 to 500 by 500). These sample areas are ...
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Fixing self-connect polygon in QGIS
In QGIS 3.2 I'm trying to clip a soil map layer and am getting invalid geometry that affects my clip result. The problem appears to be a self-intersecting polygon.
I've tried using the 'check ...
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Removing some bands or layers from a tiff using gdal
I have been working on a multiband raster image. It is a pix image. I need to just work on the 26 bands that are raster files and not the 4 bitmaps that are are also included in the pix image. I could ...
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Assigning costs to a road network : use raster or vector?
I have a road network in a PostGis database (db_routing). In another database (db_environment), I have some spatial features of the surrounding environment (trees as points and water bodies as ...
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Is raster lossy and vector not lossy?
I am new to GIS, in school for it actually, but I come from a photography / graphic design background. So that said, I always thought that vector graphics were not lossy (scale up or down, doesn't ...
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What is this UK coordinate system?
I received a dataset of Merseyside area (corresponding to the metropolitan area of Liverpool, United Kingdom, broadly defined) where the location coordinates are totally a mystery to me, and ...
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Reclass for vector data in ArcGIS Desktop?
I've got a vector dataset (in fact, OS MasterMap data) and I want to set the value of a certain field based on the value of another field. For example:
Field1 Field2
Building 20
Grass ...
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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 ...
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