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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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7
votes
1answer
1k views

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 ...
7
votes
1answer
7k views

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 ...
7
votes
1answer
245 views

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 ...
7
votes
1answer
623 views

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 ...
7
votes
5answers
6k views

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 ...
7
votes
1answer
3k views

GDAL polygonize lines

I have a raster file containing roads (left image). I polygonize the raster file with GDAL (see the script below). In the end I like to have vector lines. However GDAL only gives me something like ...
7
votes
1answer
17k views

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 ...
7
votes
1answer
3k views

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 ...
7
votes
2answers
1k views

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 ...
7
votes
2answers
949 views

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 ...
6
votes
4answers
4k views

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 ...
6
votes
1answer
849 views

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 ...
6
votes
1answer
2k views

Seeking European City boundary data?

Does anyone know any sources for free European city boundary data?
6
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5answers
17k views

Measuring the distance between lines and points in QGIS

Using QGIS - I have a vector of fault lines. I have point data in the form of a csv which I have also loaded into QGIS. I need to know how far each point is from the nearest fault line then enter ...
6
votes
2answers
1k views

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</...
6
votes
2answers
2k views

Empty vector menu in QGIS 3.0.0

I installed QGIS 3.0.0 on a PC with French as default language. After changing the language of QGIS to English, the 'Vector' menu is empty and there is a French 'Vecteur' menu. Any ideas how to fix ...
6
votes
2answers
371 views

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 ...
6
votes
3answers
11k views

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 ...
6
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2answers
2k views

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 ...
6
votes
2answers
6k views

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 ...
6
votes
1answer
3k views

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 ...
6
votes
3answers
2k views

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?
6
votes
1answer
10k views

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. ...
6
votes
2answers
3k views

Splitting lines at a specified distance

Does exist some plugin with it is possible to Splitting lines at a specified distance in Qgis?
6
votes
1answer
4k views

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 ...
6
votes
2answers
884 views

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 ...
6
votes
1answer
383 views

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 ...
6
votes
1answer
2k views

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 ...
6
votes
1answer
858 views

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 ...
6
votes
1answer
673 views

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 ...
6
votes
3answers
3k views

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 ...
6
votes
1answer
369 views

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. ...
6
votes
1answer
338 views

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 ...
6
votes
1answer
342 views

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 ...
6
votes
1answer
3k views

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 ...
6
votes
1answer
11k views

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 ...
6
votes
1answer
1k views

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: ...
6
votes
1answer
1k views

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 ...
6
votes
2answers
5k views

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 ...
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 ...
6
votes
1answer
296 views

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 ...
6
votes
0answers
167 views

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 ...
5
votes
3answers
2k views

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 ...
5
votes
3answers
5k views

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?
5
votes
2answers
8k views

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 ...
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
3answers
376 views

Finding highest point of vector with DEM [closed]

What I have is: ArcGIS 10.4. DEM raster file. Feature class "street". What I need is the highest point of the street.
5
votes
2answers
8k views

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...
5
votes
2answers
792 views

Splitting vector file by date (year) but column containing dates in Day/Month/Year format?

I am using national accident data in QGIS and quite frankly the dataset is huge as it contains every recorded accident between 2005 and 2014. I've split datasets by field for a number of vector layers....
5
votes
2answers
807 views

Problem overlapping shapefile and raster in R?

I want to plot a shapefile over a raster file in R but I can't make them overlap perfectly: the raster appears to be rotated of few degrees counter-clockwise. Is it a problem with the projection? ...