Questions tagged [vector]

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

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20 views

Clip polygon to multiple polygons

I have nine vector land use .shp and I had to make a cropland shapefile, but I thought of giving my study region polygon an attribute to be cropland, instead of digitizing it. I forgot what function ...
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0answers
26 views

Reclass and prepare raster data for use as classification training polygons in Google Earth Engine [on hold]

I am trying to do image classification. My data is int8 type with values [1, 2, 3, 4]. I want to change the data type to int and have my class values start at 0 instead of 1 so that they include: [0, ...
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0answers
20 views

Can't import WKT polygon to SNAP

I have big size Sentinel-1 image and I would like to clip it to smaller size. For that i'm trying to import shapefile but I get errors all the time: This is my polygon WKT: PolygonZ ((102....
2
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1answer
141 views

Raster origin is incorrect so not properly overlay with vector in same CRS [duplicate]

Two layers, both allegedly WGS84, one vector layer of the Midwestern US, one raster layer with coverage of the entire US. The vector layer renders correctly (coordinates are correct), but the raster ...
1
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1answer
23 views

OpenLayers get closest feature over multiple vector layers

My OpenLayers map has multiple, vector layers, each with unique features. I need a way to find the closest feature to a location across all the layers, in the same way that ...
3
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1answer
53 views

Subset point vector based on attribute classification in underlying raster

I have two datasets: A raster file containing per-pixel vegetation classifications across Australia. The file is described to have projection of EPSG:3577 https://epsg.io/3577. All additional meta ...
2
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1answer
44 views

PostGIS raster calculate average slope of 3x3 neighborhood around a geometry point

I have two tables corners_final (vector point data) dem_slope (1ft slope DEM, calculated in degrees) With this simple query I am able to extract the slope value that intersects a given point SELECT ...
2
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2answers
96 views

Transfer attribute and split line

I have two line dataset that represent the same roads: First one has very precise geometry Second one has an approximative geometry, but very interesting attribute. What I want to achieve is to have ...
3
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1answer
41 views

Splitting feature in OpenLayers 5?

How do you split an OpenLayers Vector Feature (Polygon or a LineString)? i.e ux: select feature, select a 'split' UI button, draw a split on-top of the polygon or through the line. The feature ...
1
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1answer
100 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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2answers
279 views

Tracing vector map from GeoTIFF for Garmin

My goal is to create a vector map for my Garmin GPS by tracing over a topo raster. The vector data would be exported in ESRI SHP format and later converted for Garmin. So far, I can load the geotiff ...
2
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1answer
45 views

Lat/Long co-ordinates are not plotting onto EPSG:3857 OSM basemap correctly

Excuse me if this is a stupid question, but I've honestly tried to find the answer in a few threads here on SE, and I cannot seem to follow the suggested steps correctly. Project is in EPSG:3857 (...
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0answers
19 views

Making a vector field layer out of two raster files

I am using ArcMap 10.5 and trying to make a displacement map of a glacier surface. My image correlation software output is to raster files. One contains the North/South displacement in meters the ...
4
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1answer
1k views

Generating vector contour map of fictional terrain [closed]

Originally I had asked this on the Graphics Design SE but after some realization of the question I was asking, it's probably better to ask it here. I'm making a fantasy world map in illustrator that ...
3
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2answers
3k views

Converting Raster to vector and creating polygons based on each pixel using QGIS

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 ...
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3answers
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 ...
4
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1answer
421 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 ...
1
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1answer
76 views

QGIS freezes when trying to view layer properties

As of recently whenever I try to edit the properties of a vector layer the entire program just freezes and I'm forced to end the process using task manager. I use Windows 10. Any reasons as to why ...
0
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1answer
260 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 ...
1
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1answer
56 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 ...
1
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1answer
57 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 ...
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1answer
9k views

Easy way to create buffer in QGIS 2?

In the old version of QGIS creating buffer was a 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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6answers
23k views

Moving vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it using QGIS?
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1answer
57 views

Adding Street Names and Labels to QGIS Map as separate layer

I'm trying to add all the street, river, town (all words in fact) as a separate vector layer in QGIS. I am looking to extract just the words from a London map as a PDF which I can then change to ...
3
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1answer
112 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 ...
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1answer
24 views

Rasterization - choosing attribute from attribute table for cell value of raster - why?

When a polygon shapefile is converted into a raster, an attribute from the shapefile's attribute table must be chosen for the cell value of the raster. I am pretty sure the above statement is ...
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0answers
13 views

Vector to Raster

I traced land use as forest (purple) and non-forest (Teal) in my study area of 117sq.km. from google earth. I have attached a copy of the landcover file which I have created. I need to convert this ...
2
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2answers
50 views

DEM and vector data won't match using QGIS

I have just started using QGIS for my research at university. I have a DEM comprising Italian regions of Lazio, Tuscany and Umbria. I then have a set of vector data from surveys carried out in these ...
1
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1answer
31 views

Delete unattached internal polygons in single polygon

My shapefile is a single MultiPolygon (1 feature) which has some holes, within which there exist multiple parts of this polygon, remnants of vectorization. I need to eliminate those small as shown on ...
5
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3answers
2k 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
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1answer
2k views

Deleting points which are close to each other

I have a vector file containing thousands of points. Where points are within x distance from each other, I wish to delete one of the points and keep the other (either by snapping to one point, or ...
1
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1answer
55 views

How do I find the area of a polygon covered by points of a defined size? (QGIS 2.18)

I'm using point vectors to portray 264 marked trees in a stand using the 'Random points inside polygons' tool (it doesn't matter where they are). Each point is 4.5m across (the average single tree ...
4
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1answer
52 views

Split 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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1answer
23 views

Treetop location in 3D: How can I find the coordinates (x,y,z) of point cloud's local maxima within polygon vectors?

I'm doing forestry analysis of some point cloud data and I have used segmentation procedures (i.e. watershed algorithm, etc..) to delineate the crown boundaries of individual trees in 2D. The vector ...
2
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1answer
26 views

Select raster tiles within vector polygons

I have a shapefile with polygons of all the countries of the world. I also have a raster .tiff (250m square pixels) of average wind speed per pixel. I want to select all the tiles which lie within ...
5
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2answers
2k views

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 ...
0
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1answer
44 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=...
3
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0answers
64 views

Projecting polygon when calculating its area using R? [duplicate]

I have a broad range of polygons (in vector format and in SpatialPolygonsDataFrame class), some going east-west, others going south-north, while even others span polar regions or very large ranges as ...
2
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2answers
3k views

Comparing 2 polygon shapefiles for differences [duplicate]

I have 7 shapefiles, each representing a year, all containing lots of polygons (c. 500,000). My aim is to take any 2 of them and compare how they have changed in terms of size and shape of polygon. (i ...
1
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1answer
43 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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2answers
134 views

Adding time stamps to animation slides with OSS tools [closed]

I would like to create an animation from a set of PNG files and apply labels (time lapse values) on each of the PNG files. The PNG files were actually heat maps that were generated by interpolation. ...
1
vote
1answer
43 views

Selecting a polygon area in a raster image - rasterio.mask vs roipoly

How should I select a polygon area in a raster image? So far, I have seen two methods: use a vector mask or a shapefile (some examples here: http://www2.geog.ucl.ac.uk/~plewis/geogg122-2011-12/...
1
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1answer
40 views

Selecting Matching Features in shapefile [closed]

I have a shapefile that draws up all 200 districts in a country. I want to select and colour 100 of these that I have on my list. What would be the simplest way of going about this rather than me ...
0
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0answers
30 views

How to add a vector layers to my map using OpenLayers 3?

I'm trying to add a vector layer manually to my map but i receive this error: Uncaught TypeError: b.attachEvent is not a function the code is : // adding data // Define Geometries var point = new ...
1
vote
1answer
4k views

Draw order (zIndex) of OpenLayers polygons and points in the same layer

My question is similar but slightly different to: https://stackoverflow.com/questions/5003349/openlayers-vector-features-z-indexing I have an OpenLayers Vector layer which contains polygons and ...
0
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0answers
28 views

Adding vector layers to map using OpenLayers?

I'm trying to add a vector layer manually to my map using OpenLayers 3 but I receive this error: Uncaught TypeError: b.attachEvent is not a function The code is : // adding data // Define ...
3
votes
1answer
70 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 ...
3
votes
1answer
447 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....
2
votes
2answers
689 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 ...
4
votes
2answers
338 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 ...