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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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17
votes
2answers
3k views

Rubber sheeting in GRASS?

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
13
votes
1answer
8k views

How to remove a vector QgsVectorLayer from QGis python plugin

I managed to add QgsVectorLayer in QGIS through a python plugin, for example: vl = self.iface.addVectorLayer(uri.uri(), layerName, self.dbConn.getProviderName()) But how can I remove it?
10
votes
3answers
21k views

Getting extent of layer in QGIS?

Is there a way to get the extent (bbox) of a vector layer in QGIS? I see that I can update the extent, but I am looking for the actually coordinates of the extent.
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 ...
5
votes
3answers
1k views

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. ...
3
votes
3answers
3k views

“Node tool: could not snap to a segment on the current layer” message

I have a strange issue. Editing a layer with node tool I get always the following message: "Node tool: could not snap to a segment on the current layer." This error happens to me even with a fresh ...
0
votes
2answers
198 views

Group points and compute area

In a point vector layer, how to compute area for 4 defined ranges of values of one attribute? On the example below, I want the total area for each of the 4 colours.
22
votes
3answers
1k views

How can we protect GIS data?

I have found a very interesting paper here related to this topic. I just want to have views/ideas from other professional about how we can protect GIS data using Cryptography or Digital Watermarking? ...
7
votes
4answers
9k views

Split Lines at Intersection of Other Lines

I have two line layers (roads and contours in this example) and I would like to split the roads layer every time it crosses/intersects a feature on the contour layer. I can't seem to find a tool that ...
13
votes
2answers
15k views

How can I programatically create and add features to a memory layer in QGIS 1.9?

I had a working plugin in QGIS 1.8 which read data from an MSAccess database and added it to a series of memory layers. There is some processing involved in the interim so I don't think simply using ...
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?
8
votes
3answers
9k views

Removing columns in a SpatialPolygonsDataFrame in R?

My spatial polygon data frame (SPDF) contains too many columns (variables) and I want to remove most of the columns entirely. I know how to do this with a regular data frame in R, but I am unsure ...
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 ...
15
votes
3answers
11k views

Finding and merging duplicate points in ArcGIS Desktop?

I have two point shapefiles: Red and Blue. Each point shapefile has a z value which represents a radius (i.e. represented as buffers in the example). A duplicate point is defined as a point that ...
10
votes
2answers
812 views

What's the batched Refactor Fields tool “field mapping” syntax in QGIS?

In QGIS, there is this nice tool "Refactor Fields" in the Processing Toolbox : Using it on a single layer is fairly straightforward. However, when you plan on using it in a batch mode, one can see ...
5
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 ...
4
votes
1answer
3k views

How to use a sld file with Openlayers using OSM data?

My app, made with openlayers, displays building data called from overpass api. var data_url = "http://overpass-api.de/api/interpreter?data=(way[building](bbox);node(w););out body;"; //main working ...
7
votes
4answers
20k views

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", ...
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: ...
11
votes
1answer
3k views

Is there a way to split polygons by several lines in QGIS?

I have a polygon (.shp) and a line (.shp) layer. I want to split the polygon in several pieces along the lines that overlap the polygon. Afterwards I want to edit each polygon separately (attribute ...
8
votes
3answers
2k views

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 ...
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 ...
5
votes
2answers
11k views

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 ...
4
votes
2answers
488 views

Label rotation values in DXF imported into QGIS

When loading a dxf in QGIS, the line type files load in ok, however all text rotation values are lost when loaded into QGIS. This is most obvious when you load in OStext.dxf (please see grab_Mar.22....
2
votes
2answers
14k views

Convert vector data with irregular points (no grid) to raster with QGIS?

I am aware that how to convert a vector layer to a raster layer is a quite frequent problem and that there are many questions and answers dealing with it. However, none was helpful concerning my ...
1
vote
2answers
517 views

Converting Direction Of Travel OSM vectors from “system” to another?

I have a painful doubt according Direction of Travel (DOT) vectors in OSM data. I'm using ArcGIS10, and a OSM data shapefile. I have a OSM road layer, that has many "Both ways" vectors and many "One ...
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 ...
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?
5
votes
1answer
510 views

How to suppress polygon boundaries shared by objects of same type in QGIS?

Given polygons - like landcover in OpenStreetMap or street areas in cadastre - how can one suppress those polygon boundaries which are shared by objects (features) of same type in QGIS (see figure ...
5
votes
2answers
2k views

Scaling vector field marker arrow based on attribute?

I have discovered how to create vector lines to indicate flow direction and velocities. With a "vector field marker" symbol layer type, the lines lengths vary based on the data attributes. However, ...
4
votes
1answer
419 views

QGIS's “Points in Polygon” counts zero in every census tract

I am mapping the location of incidents of asthma using QGIS. I would like to count how many points are in census tracts to better understand the areas where asthma occurs most frequently. My map ...
4
votes
1answer
5k views

How to get all Vector layers from OpenLayers map?

OpenLayers.Map object exposes a method call getLayersByClass. How do I use this method to retrieve all of the Vector layers from the map? I tried map.getLayersByClass("Vector") but this returned an ...
4
votes
1answer
489 views

How to make a vector layer with Hebrew caption in Qgis?

I am working in Qgis and need to make layers with Hebrew caption. When I make a new layer and write a word in Hebrew, in this case on a point vector layer that I made, it looks just fine. However, ...
3
votes
2answers
1k views

Creating indexed vector grid in QGIS?

at the moment I am trying to create an indexed vector grid via "vector -> research tools -> vector grid...", in the following format: A1 A2 A3 ... B1 B2 B3 ... C1 C2 C3 ... .. .. .. The creation of ...
2
votes
1answer
443 views

QGIS: ESRI shapefile .shp no longer appears in list of file types under Add Vector Layer

I recently installed QGIS 2.18.4 after using ArcMap for many years. I want to add several existing ESRI shapefiles (.shp) created in Arc, to a QGIS project. To add a new layer in QGIS, I select the "...
2
votes
1answer
1k views

Creating new empty memory layer with fields scheme from other layer in QGIS?

Being new with python so far, I got inspired by this answer: https://gis.stackexchange.com/a/155988/8202 to dive into it a bit. When creating features in a new target layer from an existing source ...
2
votes
2answers
85 views

Deleting vector lines beyond image extents using QGIS?

I am using QGIS 2.2 I have one vector line layer (roads) that stretches beyond my base image (see below). I wish to have the roads "clipped/trimmed or deleted" right at the edge of the image's ...
2
votes
1answer
86 views

Creating new lines based on another line feature and point feature using QGIS?

I have line layer (roads) and point layer (milestones) and I need to create a new line layer based on roads layer, where the start and the end points will be milestone points. Can you advise me some ...
1
vote
1answer
2k views

openlayers- WFS- Cross-domain problem

I got the typical cross-domain problem when access to WFS layer by using openlayers, XMLHttpRequest cannot load http://XXXX/geoserver/ows?service=WFS. Origin http://XXXX is not allowed by Access-...
1
vote
1answer
4k views

How to indicate flow of a watershed feature?

While tracing and digitizing rivers, streams, rivulets, etc., is it possible to indicate the direction/flow in the shapefile on QGIS? I'd like to avoid using map labels. Ideally, when done tracing, I ...
1
vote
1answer
444 views

How to remove line segments from a polygon for borders on a map in QGIS?

I am making a figure of the northern Himalaya, and in it are India, China, and Pakistan. These countries have disputed borders so I want to display these borders like they are displayed on Google Maps ...
1
vote
2answers
162 views

Exporting point pattern fill as vector data in PDF

In QGIS 3.2, I have a map with parks/other green areas to be displayed as a simple vector point pattern fill. No matter what I do, the pattern fill is always exported to PDF as raster data, which is ...
1
vote
1answer
326 views

Aligning Raster and vector layer using PyQGIS when they do not match?

Relatively new to GIS. I've created a vector layer of points based on row/col position of high population density pixels in a raster layer. The layers do not align even though they have the same CRS, ...
1
vote
1answer
814 views

Projecting vector data in QGIS?

I'm running QGIS 2.2 on Ubuntu 14.04. Trying to project data gives me a hard time right now. The last time I did that was in 2.0 and I basically changed the projection by saving the data as a new ...
1
vote
1answer
552 views

Snapping one vector layer to another

Is there anyway to snap one set of vectors to its nearest neighbor vector in another feature class? For example, I have a road feature class and a feature class of bridges and I want to snap the ...
18
votes
1answer
340k views

What is the difference between Vector and Raster data models? [duplicate]

From: http://support.esri.com/en/knowledgebase/GISDictionary/term/vector%20data%20model vector data model: [data models] A representation of the world using points, lines, and polygons. Vector ...
19
votes
3answers
978 views

Buffer neighbouring polygons without overlap using QGIS

Is it possible to create a buffer around neighbouring polygons, so that the new polygons do not overlap? Preferably in QGIS but any other tool will do. So instead of the first result I would like ...
16
votes
2answers
429 views

Toward a protocol for encoding vector data as image

This is a follow up to this question: Creating Vector Polygons with rendering performance like GISCloud? In his answer, Yagi outlines a rationale for encoding geographic information in an image ...
11
votes
1answer
14k views

QGIS moving the layer/all features using Vector Affine Transformation

I'm using QGIS to analyse some flight tracks which were produced using a different software. Now when they are on QGIS the reference point of everything is on 0,0 which is the aerodrome reference ...
8
votes
3answers
3k views

30,000 data points… can this be reasonably served using openlayers?

I'm trying to tackle a web GIS problem and need to figure out the best strategy. I have a map with 30,000 cells on it forming a grid for the province of Alberta. I have a list of data points for ...