Questions tagged [vector]

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

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votes
1answer
35 views

Coordinates of an area on a raster in QGIS

I am new to GIS and I have to do the following: I have a GeoTIFF raster file of a map with some features like clouds and water bodies. It is a satellite image. My images are taken from a snapshot of ...
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0answers
31 views

QGIS: Polygonize error

Running the Polygonize tool in QGIS keeps generating the following error: Processing algorithm… Algorithm 'Polygonize (raster to vector)' starting… Input parameters: { 'BAND' : 1, '...
1
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1answer
28 views

Polygonize specific raster values QGIS

I have a raster of 36 classes of the land cover in South Africa. However, I only need 4 of these classes and create a polygon out of these 4 classes combined. I have now used the raster calculator to ...
2
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3answers
4k views

Splitting raster in QGIS? without cliper

I have polygon grid layer and raster image whitch want to split with my grid layer to have 9 new raster layers. I was doing it like this guy but my QGIS stop working and shut down every time when I ...
2
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0answers
19 views

Query of line direction histogram plugin

I was wondering if anyone could explain how this plugin works I have had a play around with it and I do like how it visualizes how vectors are orientated. However I ran one and opened the CSV file ...
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0answers
144 views

Determining Affine Transformation Parameters? [duplicate]

I am trying to use the qgsAffine plugin to do the transformation but I have no idea in its usage. How to find the transformation parameters? I found some posts suggest using the OpenJump How to use ...
5
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2answers
2k views

Seeking QGIS affine equation?

I am at the mercy of a govt authority who have provided utility information in a cad format with a 0,0 origin and a nonsense grid. About a dozen files, the grid and origin are entirely arbitrary. To ...
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0answers
15 views

Calculating the distance of raster cells from a vector within a polygon using QGIS

I am quite new to QGIS and am trying to use QGIS 3.6 to create a raster layer of calculated values of the minimum distance of each cells within a polygon (orange) from a vector (the river channel in ...
2
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1answer
28 views

Store results including style in vector format for QGIS, ArcGIS [closed]

As I am wrapping up my project, I would like to make my results available for download. There are however many flavors to choose from and I was wondering what format is best. My criteria include: ...
1
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1answer
68 views

Automatic correction of many topological errors in shapefile?

I have a database with topological error. In particular I have an overlay of polygons. I would like to correct these errors. I thought to use an automatic procedure since I have a lot of errors. I ...
0
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0answers
12 views

Country boundaries shapefile pre-1980 [migrated]

I'm looking for a shapefile with the country boundaries as they were when Czechoslovakia existed as a country. Is there any online open source resource where I can find historical country boundary ...
1
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2answers
33 views

Is it possible to clip raster by mask layer with a rule that it only clips raster if the shapefile overlaps by 10%? Using QGIS

[ QGIS ] Is it possible to clip a raster when the shapefile overlaps with it by 10%? Clip raster by mask layer tool is fine for Ontario (left) but makes me lose a lot of data from smaller locations (...
2
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0answers
19 views

How to delete a file after processing an algorithm in QGIS 2.18?

I am trying to delete an intermediate file ("Temp_merged.shp") after running the singleparts to multiparts algorithm in QGIS 2.18. import glob, os, processing path_to_shp = "C:/Temp/Tracks/" ...
3
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1answer
67 views

Merging all vector files within directory with QGIS?

I am unsuccessfully trying to merge all shapefiles in a given directory using QGIS 2.18. I do not want to navigate to the folder using QGIS GUI tools. Instead, I want my script to include all ...
2
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3answers
334 views

Extracting a small subset of an .sdc file

There are some line features in the form of an .sdc file. I do not need all the data in the file, just a very small subset of it. I understand that .sdc files are highly compressed, and my file is ...
1
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1answer
80 views

Turning “normal” Vector Data into a GIS

I have a map in Adobe Illustrator with several vector layers. ( Therefore the vector data have no spatial reference and no attributes. What is the best way to turn these vector data into a GIS and ...
1
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2answers
505 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 ...
3
votes
1answer
372 views

Aligning raster data to vector data in QGIS?

I'm in the midst of aligning century-old maps (of Paris) to vector data of the modern same: Qgis' Georeferencer tool works fine, but doing the entire city that way is a gargantuan task. Paris hasn't ...
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0answers
32 views

Vector map (rivers) to Raster. [ **ERROR 1: Wrong value for -outsize parameter.**]

I want to transform this vector map: To something like this I only tried to convert the vector map through Raster> Conversion> Rasterize But I get this Error: QGIS version: 3.6.3-Noosa QGIS code ...
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0answers
16 views

Can QGIS be used to calculate the up-slopes (total area draining to a specified point) of multiple separate points simultaneously?

I am trying to calculate the area draining to a point of 240 separate points using QGIS. At the moment I'm using the Saga - Upslope Area algorithm to individually work this out for each of the 240 ...
2
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0answers
44 views

Isolating main polyline using QGIS?

I am trying to convert a line shapefile with branches into just one polyline, actually deleting every other diramation. Imagine something like this: :________|__________|____|||______ into :...
21
votes
3answers
9k views

How to access feature classes in file geodatabases with Python and GDAL?

I am trying to access a vector dataset in a ESRI File Geodatabase using Python + GDAL. I have successfully compiled GDAL with the file geodatabase API. The FileGDB driver is working correctly since ...
1
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1answer
45 views

Python: Convert shapefile to GeoJSON whilst stripping and renaming fields

I'm writing a Python script to convert shapefiles into GeoJSONs but I would like to remove many of the fields as they are redundant and rename the ones I am retaining. Here's an extract of where I ...
0
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1answer
24 views

Keeping minimum when converting from shapefile to raster?

I have a shapefile that I am trying to convert to raster. The shapefile has overlapping polygons. I would like to keep the minumum value of these overlapping polygons when converting to raster. ...
0
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1answer
149 views

How to make layer stacking in envi for landsat 8

I downloaded landsat image 8 and i made layer stacking for RGB layers in ENVI (Bands 4,3,2) to classify the land cover types. but the problem appeared when i conducted supervised classification. I ...
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0answers
28 views

Clipping by mask results in blank output

After clipping by mask in QGIS 3.6 the output file has been blank (empty). Raster file and vector mask file have the same projected CRS: USER:100029 - * Generated CRS (+proj=igh +a=6370997 +b=...
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1answer
8k views

A easy way to create buffer in QGIS?

In the old version of QGIS creating buffer was relatively complicated task. Basically you had to save your layer as a new one with metric cylinder CRS in order to calculate distance correctly. If ...
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0answers
28 views

QGIS 1.8 and Shapefile units in seconds [closed]

I have QGIS 1.8 on Centos 6.5 (I cannot update this system). I have a problem with opening a shapefile layer with units in seconds (created in ERDAS). QGIS doesn't display and doesn't save ...
2
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1answer
85 views

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 ...
0
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3answers
90 views

Converting raster pixels to vector cells?

Is there any way to convert raster pixels to vector cells? I mean each pixel to a polygon. I tried the SAGA tool 'Raster values to points' by choosing cells option instead of nodes option. As a ...
2
votes
1answer
86 views

Retrieving lines radiating from point with v.select in GRASS GIS 7.6

I am attempting to select lines that radiate from a point using v.select in GRASS GIS 7.6 (also tested with 7.4.4) in Windows 10. I start out with 48 lines radiating from a point every 7.5 degrees. ...
15
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6answers
9k views

Defining layer CRS and avoiding CRS dialog in PyQGIS?

There is an existing Shapefile, which I want to add. At the moment my code looks like: self.iface.addVectorLayer(self.shpFilePath, "Track", "ogr") It works fine, but i want to define the crs within ...
1
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1answer
46 views

Calculating areas of polygons that match with overlapping raster threshold value?

I have a polygon of districts (districts.shp) and a raster of rainfall (rainfall.tiff). I want to calculate the area of each district that saw rainfall greater than various numbers. I'd like to ...
0
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0answers
18 views

Loading layer with QgsVectorLayer in standalone PyQgis 3

I can't seem to figure out why my layer won't charge in QGIS. After reading many topics, it seems to be linked to the prefix path. However changing this, does not seem to work (I tried around 10 ...
0
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1answer
30 views

Correcting topological errors in QGIS?

Using the topological corrector inside Qgis I have identified overlapping polygons. My situation is represented into this image My polygon of interest is located below another polygon (the red ...
1
vote
1answer
23 views

Is there an alternative function which does the same thing as clip raster by masked layer on QGIS?

I am having some technical problems with the clip raster by masked layer and I faintly remember using a different method a long time ago for a similar problem. Anybody familiar with another function?
1
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0answers
35 views

Vector tile generation

I have a full planet imported in PostgreSQL with imposm3. What is the best way to generate vector tiles (MVT in .mbtiles) from PBF/PostgreSQL with maximum hardware utilization (distributed generation ...
4
votes
2answers
119 views

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 ...
5
votes
2answers
114 views

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 ...
1
vote
2answers
78 views

Problem with intersecting lines over a polygon layer in QGIS

I have a shapefile with lines (a road network) and I want to intersect it over a polygon layer in order to finally have a polygon layer (each cell has an ID number) with the intersected lines for each ...
1
vote
1answer
36 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 ...
1
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0answers
131 views

Converting vector in NED to ECEF? [closed]

I have a geodetic WGS84 position, lat, lon, alt, and direction cosines from the same point, uN, uE, uD. I'm brand new to geodetic/ecef conventions. How do I take a vector (say, a unit vector with ...
3
votes
1answer
390 views

Generating customized vector OSM map files from OpenStreetMamp and other data?

I am looking for a way (e.g. tutorial?) to generate my own customized (offline) maps in OSM format. By "customized" I mean adding data (not just define a region of interest) to an existing OSM map (e....
3
votes
1answer
86 views

v.reclass no output

I want to reclassify a polygon vector and use v.reclass. Feature type: boundary Name of column: LBA Reclass Rule: I use a .txt with the following content: CASE WHEN LBA = 68 THEN 2 WHEN LBA = ...
3
votes
1answer
244 views

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 ...
0
votes
2answers
39 views

Reclassifying vector polygons based on text string to integer using Python Parser of ArcGIS Field Calculator?

So I am trying to reclassify a text string by searching for bits of strings and converting those strings to an integer value in a new field within the field calculator. e.g. I want to find all values ...
3
votes
1answer
63 views

Fixing self-connect polygon 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 geometries', and ...
0
votes
2answers
604 views

Getting feature coordinates from dynamically loaded layer using OpenLayers?

i want to load the coordinates of a point that is stored inside a vector layer and the vector layer is stored inside a layergroup. I do load the vector layers dynamically to the layergroup "Runs". So ...
1
vote
2answers
596 views

Seeking data source for worldwide urban/statistical areas as polygons?

I am looking for a shapefile (or any format really) that has worldwide coverage of major urban areas / statistical areas as polygons with names. Similar to what the US census Bureau' Core Based ...
7
votes
5answers
9k views

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 ...