The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [vector]

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

Filter by
Sorted by
Tagged with
1
vote
0answers
43 views

In ArcMap, how to create random points of a specific amount in each polygon?

I am doing an accuracy assessment of land-use product and need random points as test points. What I'm trying to do is to generate different numbers of random points in different polygons (like 5 for ...
4
votes
1answer
69 views

Extract value from vector to another

I have two vector (shapefile) data. One contains soil order for county, and the other one contains boundary for each county. I want to extract the soil order for each county by using county boundary. ...
2
votes
0answers
32 views

Issue with vector grid and calculating area QGIS

I'm trying to determine the area of occurence from a large polygon superimposed onto 2km x 2km grids. The goal is to have a slightly coarser answer then a straight area of the original polygon as the ...
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
0answers
40 views

How could I assess the value of a polygon according to the value of his neighbor?

I would like to know if it is possible to give a value to a polygon, according to the value of the polygons around. I want to assess the ecological integrity of an aquatic network (lakes, pond, ...
0
votes
1answer
20 views

Vectorising lines appear as a mixture of bubbles and lines from raster map

I have these road raster maps which I have reclassified into binary images to try and vectorise. However, when I click on vectorise and generate feature, it comes out as a mixture of bubbles and lines ...
1
vote
1answer
40 views

'Regular Points' vector layer in Bonn

I've downloaded the bonn version of QGIS. Using the 'regular points' vector analysis tool, I've set some 5m regular points over a field so that I can use the x,y coordinates to plot them and measure ...
1
vote
1answer
66 views

Discerning dwelling types in QGIS? [closed]

In QGIS, I want to discern between a number of building types, based on topology. I have data on buildings, parcels and addresses. I'm having a hard time to discern between row/terrace, end-of-...
3
votes
1answer
358 views

Digitize objects in a LiDAR point cloud?

I am working with LiDAR point cloud data of road networks. The goal is to digitize all visible objects like hydrants, streets, sidewalks. My input data is available in LAS or ASCII format. My first ...
1
vote
0answers
80 views

Cluster spatial - cannot allocate vector

I'm trying use this code for create cluster spatial in R, I get from @ssanch: # example data from the thread x <- c(-22.83982, -23.49961, -27.08745, -22.98890, -19.92278) y <- c(-47.20671, -46....
1
vote
1answer
218 views

pyqgis 3 setup vector labeling not working

I have a standalone pyqgis3.2.1 (Bonn) application that can display maps (vectors, rasters). I tried to setup labeling of vector layers using the following codes, but it only works for point layers, ...
1
vote
0answers
29 views

Create a path in mapping software and export as vector?

Is it possible to map a route in any mapping software (OpenStreetMaps, Google Maps/Earth, QGIS, etc. preferably Open Source or free) and export this route as a vector (PDF, AI, SVG etc.)? I'm only ...
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 ...
1
vote
1answer
64 views

How do I create a line with fixed size from a single point in QGIS?

My question pretty much sums up my problem. Basically, I have a layer containing points: And I need to convert them into lines with fixed size (25 meters). I don't care if the point will be taken as ...
0
votes
1answer
57 views

Count how many times an attribute in a polyline intersects a polygon in QGIS

I am trying to count how many times a polyline with a specific attribute intersects a polygon in QGIS. For example, I have a polyline with a feature class called "size", this contains a text value i.e....
5
votes
1answer
332 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. ...
2
votes
1answer
89 views

Read a Raster Band Value inside of a VectorLayer in QGIS [closed]

How to read pixel values in RasterLayer that intersects line features of VectorLayer, applying Python in QGIS?
8
votes
1answer
906 views

Split up shapefile into little shapefiles

I have a very large shapefile (all the roads in RI). I need to split it up into chunks so that I can process the file with multiple worker threads in Python. So far I have created a grid in QGIS that ...
2
votes
1answer
631 views

Distance to Nearest Hub QGIS not working when 'hub' is a line?

QGIS 2.18.20 working in CRS: WGS 84/UTM Zone 35S (EPSG:32735 OTF), with shapefiles of map features (roads, river, point water sources) reprojected from WGS84 EPSG:4326. All shapefiles have been ...
1
vote
1answer
41 views

QGIS Union erroneously creating gaps

I'm trying to do a union between two Polygon Shapefiles, but when I do Vector > Geoprocessing Tools > Union I have the odd issue where most of it works fine, but some areas are returned in the union ...
0
votes
1answer
33 views

Openlayers 3.10 can't display features added manually

I'm trying to add features manually to vector layer but with no luck. This is my code: cords[0] = { [19.1820888104, 49.6835693017], [19.1819108957, 49.6850423191], [19.1846518426, 49.6853635871], [19....
2
votes
2answers
194 views

Clip Raster by Attribute values

I have a raster which I want to do a clip with a vector layer (polygon) using its atttribute values. What I have done so far is the folliwing: from qgis.core import * from qgis.gui import * import ...
1
vote
1answer
288 views

Attribute Error: 'unicode' object has no attribute 'extent'

I keep getting this error from this line. arcpy.CreateFishnet_management(os.path.join(Output_Folder, "Full_Grid.shp"), str(NAR_U9.extent.XMin) + " " + str(NAR_U9.extent.YMin), str(NAR_U9.extent.XMin)...
0
votes
0answers
36 views

Polygon interpolation neighbour average?

I am trying to estimate empty values based on a polygon layer we received from another study. Is there a way to calculate an average value for polygon A based on neighbours B,C, etc that border it? I ...
1
vote
0answers
50 views

QGIS: Fill shapefile vectors with grayscale based on elevation

I am very new to this and feel like this is probably an easy answer, but after days of searching this forum I still am unsuccessful. I have shapefile data with elevation and I want to create a raster ...
1
vote
2answers
667 views

How to assign raster layer's colors to polygons in QGIS?

I have a georeferenced raster file showing parcels of a town with different colors (yellow for the category single-household residential, green for agricultural areas, etc.). I also have the shapes of ...
0
votes
0answers
101 views

Opening National Land Cover data?

How do I open the National Land Cover data in QGIS 3.0? Attached is an image of the files. It looks like it's an .rrd file.
2
votes
2answers
999 views

How are the coordinates for multipolygons arranged?

How are the coordinates for a multipolygon (i.e. polygon with a hole in it) arranged? Do shapefiles and geoJSON files always save the coordinates for the outer ring first? I'm asking because I ...
0
votes
1answer
177 views

How to get parcel boundaries with tax roll, land use, and zoning info?

How do I get parcel boundary shapefiles with tax roll, land use and zoning info included? Is it possible to just create the parcel boundaries data from scratch, i.e. could I create parcel polygons in ...
-1
votes
1answer
183 views

Get PostGIS geometry data and display it on map using GetMapRequest

How can I get the data from PostgreSQL db and display on map using GetMapRequest? I have done connecting the PostgreSQL db which contains the geometry data. Now I want to redirect that data to map ...
1
vote
2answers
161 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 ...
2
votes
1answer
239 views

How to merge all layers in QGIS project using 'merge vector layers' within PyQGIS

I am trying to use the 'merge vector layers' tool in PyQGIS to merge all of the layers in my QGIS project into one shapefile, as part of a larger script I am developing. I tried this script, but I get ...
1
vote
3answers
424 views

Creating a source and a layer from vector tile features in Openlayers

So I retrieve all my features from a vectorTile layer (PBF from Geoserver), and now I want to recreate a layer by filtering on those features and getting only those that satisfy a request. I ...
1
vote
1answer
242 views

Getting data on area where shapefile overlaps raster file using QGIS?

I have attached an image to help explain what I am asking. I want to get the average value of where the heat map crosses over each municipality in the shapefile and export those values into a ...
8
votes
4answers
1k views

Understanding resolution in vector maps?

I'm developing a vector maps with detailed features such as road edges, cross walks, traffic lights , street lights etc., by using 3D points (x,y,z) without geo-referencing, generated from stereo ...
1
vote
1answer
59 views

Statistics for point data within each polygon using ArcMap?

I think this is a pretty basic GIS operation but I'm not sure how to do it. I have hundreds of polygons, and within each polygon there is point data (see picture). The point data has a field "Type" ...
1
vote
1answer
286 views

How to calculate the overlap of two polygons in PostGIS

I am trying to calculate the percentage overlap of two vector polygon layers and saving the result as a separate column. The code below is working: CREATE TABLE parcels_all_shapefile_new AS SELECT ...
3
votes
4answers
371 views

Calculate length of huge vector lines dataset

I have a MultiLineString vector layer from which I would like to calculate the length. I have tried to calculate the length with the Field Calculator by putting in the expression $length. The ...
0
votes
1answer
822 views

Request a WFS layer using OpenLayers

I am new to OpenLayers and GeoServer... can someone please help me to show a WFS layer... here is my code: const vectorSource = new ol.source.Vector({ format: new ol.format.GeoJSON(), url: ...
1
vote
1answer
111 views

Mask a Raster layer in QGIS using a vector layer with multiple polygons

I would like to extract statistics from a raster file based on a land cover classification vector file, however the land covers (features) are not contiguous (see pic). In the example below, I would ...
1
vote
1answer
137 views

Only show buffers that overlap geometry

I have multiple sites that are surrounded by a buffer. I also have a layer which corresponds to areas affected by changes. I am trying to filter out buffers that are not overlapped by the change ...
0
votes
1answer
145 views

Using Presence/Absence method in QGIS?

I seek advice for calculating presence/absence of features in QGIS. I have a polygon dataset of boundary outlines and a number of other datasets which I want to compare it against for presence/...
1
vote
1answer
55 views

Is there a vector format for depicting continuous 2D polygons with attributes?

I'm working within the QGIS environment and looking for a 2D continuous vector attributed editable file format to work with. My goal is to find a vector layer that has different features with no ...
4
votes
1answer
1k views

How to change 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 ...
2
votes
2answers
636 views

Changing vector extent in QGIS

I've been looking for a manner to change a vector extent in QGIS, but it's unsuccessfull! I want change extent because in the past, I had problems to convert vector to raster. I try present the ...
0
votes
0answers
197 views

Saga difference vector tool

My QGis Difference tool doesn't work really well, it gives me lots of little squigly lines. i read in the link below there is such a thing as a vector diffence tool from SAGA, but i can't find it. ...
6
votes
1answer
325 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 ...
0
votes
1answer
173 views

QGIS 2.18 buffer [duplicate]

I'm trying to use fixed distance buffer, and had a few questions. One, what units is the distance being measured in? I assumed meters, but after doing a test run it clearly isn't. And two, what is "...
1
vote
1answer
40 views

Non-destructive improvement of vector layer (shapefile) representing a road network?

I have a QGIS project with some vector layers backed by shapefiles. One of these layers contains all the roads, and I would like to "improve" it: It is organized in a way that each vector feature ...
1
vote
0answers
254 views

How to open memory data with ogr in rasterstats function?

I would like to reuse vector data created in memory in another function called rasterstats (source code, documentation): I have a function that creates vector data: def createPolygons: ...