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

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2
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64 views

QGIS 2.12.3 Crashes on buffering line vectors

I'm using QGIS 2.12.3 and I'm trying to create a buffer of 100 mt around a line vector using the Vector - Geoprocessing Buffer tool, but qgis crashes at every try. I've already checked that the RS of ...
2
votes
1answer
52 views

Adding new columns from other shapefiles - Land use density

New here but I've been following the stack exchange for a while to get many answers on my newbie journey in GIS. I'm trying to find out how to merge different point in polygon classes by column. ...
2
votes
2answers
66 views

Split Vector Points/Polygons by Vector Grid and assign to relevant grid

I have 3 vector shapefiles (1: Point, 2: polygon, 3: vector grid) that I would like to combine so that the points and polygons are 'assigned' to the relevant grid cell within which they are contained, ...
3
votes
1answer
34 views

How to combine 2 vector shapes created from raster files

In Qgis 2.12 Lyon, using windows 10 I downloaded 2 raster files from an area of my interest. The rasters were on information about precipitation and evapotranspiration. Each cell had a value. I ...
1
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0answers
38 views

QGIS polygonize tool not working [closed]

I am having a problem using QGIS ver 2.10.1 Pisa. I am trying to use the polygonize function on a raster .tif image, and it runs, but only produces a thin sliver of polygons at the top, then stops ...
1
vote
2answers
54 views

check the “quality” for (poly-)lines (density of vertices)

I want to check the quality of digitized tracks. I suppose, that a track with a lot of regular vertices has got a good quality. And a track with less regular vertices has got a poor quality. Maybe, ...
1
vote
2answers
86 views

How to combine two polyline shapefile together

Here is my question Two shapefile: * A: represent the outer boundary of the city area * B: represent the inner boundaries of the city divisions. I want to * Combine these two shapefile * ...
0
votes
0answers
26 views

How to combine population density data to land use data?

i have census data and land use data in vector format. I tried to combine the population density vector data with land use data set, but every-time it gives me wrong output. Moreover, my land use ...
1
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0answers
16 views

How do I generate a sampling path by numbering points?

I need to number points from left to right and then the next row of points the numbering must continue from right to left, then again from left to right the row thereafter - and so on, and so on. ...
2
votes
1answer
60 views

PyQGIS: Change attribute value doesn't work, results in NULL

I am writing a QGIS plugin, which at one point attempts to change several attribute values on a layer. However, in the end no changes are made. If I punch similar code into the built-in Python ...
4
votes
1answer
127 views

Automatically updating user-edited features in QGIS plugin

I am working on a plugin for QGIS (2.12). It uses data stored in an Spatialite database. When the user creates a new feature, the plugin should: update the feature attribute table (the popup form ...
3
votes
2answers
197 views

QGIS Real-Time Vector Layer Creation

QGIS is running on my Windows PC. I have a CSV file on my PC that is remotely updated with values of a raspberry pi's GPS position and some wifi-status readings. Is it possible to create a vector ...
2
votes
0answers
36 views

Combining adjacent shapefiles and merging neighbor polygons currently divided by quad boundaries

The project I'm working on has been mapping ecological sites in ArcGIS on a quad-by-quad basis for the past 10 years. When entered into GIS, each quad has its own shapefile and the sites are cut off ...
2
votes
1answer
38 views

Error when trying to subset a vector to a dataframe

I'm not sure if I've used the correct terminology in my title, so please forgive me if that doesn't entirely make sense. For the sake of reproducing my example, I've created a dummy example. As ...
6
votes
3answers
89 views

Select all polygons that are completely within a circular buffer

I made several buffers around some points. Now I want to select all polygons that are completely within this buffer. My problem is that I also get the polygons that are partially outside of the ...
4
votes
0answers
60 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 ...
0
votes
0answers
22 views

Is there a way you can see the spatial query that vector uses?

I am using geoprocessing-tools --> intersections to calculate which points are within my circular buffer. It works fine but I want to know what query(/code) vector is using so I can add some ...
1
vote
2answers
77 views

Vector to raster conversion [solved]

I'm using GRASS but, in case, I'm also familiar with R and QGIS. I'm trying to convert a vector area map into a raster one. My problem is that the resolution of the raster is too low (and I can't ...
0
votes
1answer
38 views

Determining of vector dataset single files to specify its size on a disk

I wonder how to get size of disk space that a specific vector dataset occupies on a disk. I didn't find any ogr2ogr util or OGR Python method that can return a list of files that belongs to given ...
1
vote
1answer
74 views

Can multiple point symbols be stored in one QGIS layer?

I'm new to QGIS, indeed fairly new to GIS systems in general. I have been asked to create about 20 small maps for a local historical society. The maps are for walkers to follow various routes passing ...
0
votes
2answers
56 views

how to draw coordinates along the lanes using MultiLineString instead of LineString

I trying to draw lines along the path of the lanes on the map using openlayer3 but i am not getting any lines on the lanes there is no error in the developers console as well <!DOCTYPE html> ...
1
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0answers
32 views

Using arcpy to add several rasters

I need to do some raster/vector processing on some non-overlapping tiles. My python script needs to find the correct tiles and then extract the raster values and count them up. My script needs to be ...
0
votes
0answers
21 views

GRASS: strange classification output and reject map from “i.maxlik”

I am trying to perform a supervised classification with "i.maxlik". I have three bands: 1) elevation (a dem); 2) reflectance (derived from Landsat ETM+ band4); 3) cumulative solar radiation (derived ...
2
votes
1answer
47 views

Error while executing v.rast.stats command in grass plugin in qgis

I have a vector polygon which I imported in grass. I also have a raster from which I have to extract the value. I ran v.rast.stats command in QGIS 2.12. The command was executed with error. The error ...
0
votes
1answer
36 views

Intersect elevation interpolated from CAD file in ArcGIS

I have two datasets - contours and vector (water, roads,...) Vector layers were used as breaklines to generate the contours. Then the contours were generalized a bit. For quality check I need to ...
0
votes
0answers
28 views

GDAL/OGR in C++: Opening a vector file

So I'm making a vector file this way: OGRSFDriverH hDriver=OGRGetDriverByName("KML"); OGRDataSourceH hDS=NULL; hDS = OGR_Dr_CreateDataSource (hDriver, fname_dst, NULL); //I add layers ...
3
votes
1answer
50 views

Vector differencing fails in QGIS (due to geometric errors)

I was trying to correct the country shapefile of Uzbekistan for Gas flares: Input layer (the UZB_adm1) differenced by this layer. In QGIS the result was that the overlapping regions - where the ...
1
vote
1answer
77 views

GDAL/OGR in C++: Merge multiple vector datasets to single [closed]

I need to merge multiple kml files into a single one. I found that I could use "ogr2ogr -append" but I have to do it through c++ and my Google-fu hasn't been successful so far. So, any ideas? Also, ...
3
votes
1answer
99 views

How to ‘invert’ or ‘reverse’ a vector cutline when gdalwarp'ing a raster?

I have a raster of North America and I'd like to remove the larger lakes from it, replacing them with the same no-data value as the original raster. So I downloaded Natural Earth's 10 meter lakes ...
0
votes
1answer
64 views

Increasing size of buffer based on field in ArcGIS for Desktop?

I am using vector data from a CSV file and ArcGIS. I can use the Geoprocssing tool Buffer just fine, I use these parameters and ArcGIS does produce what I want, however it is way to small (my ...
3
votes
1answer
113 views

Why can't I clip my Shapefile?

I've tried all of these solutions (How to clip a line layer based on polygons with QGIS?) and still cant clip a shp file. I'm trying to create a coastal shp file for one region (NW France) from a ...
1
vote
2answers
36 views

Resetting 'cat' column in GRASS?

I've got a regular polygon file that looks like this: Unfortunately, this file stems from a v.overlay so that the 'cat' values are are a bit messed up. I would like them e.g. to start in the upper ...
1
vote
1answer
23 views

Making buffer zone based on size of attribute using ArcGIS for Desktop?

Buffer zone isn't really the correct word, sorry, but I am not sure how to explain it. I want to make a circle around each attribute based of the size of the value, similar to a bubble map. However, ...
2
votes
0answers
60 views

Regridding vector values

I'm trying to regrid and interpolate vector values from WAM model output. I got WAM model netCDF output in rotated grid, I need to interpolate it to another grid which is some variant of LAEA ...
2
votes
0answers
81 views

QGIS 2.12 map composer issue with vectors

i am making a map that includes all kinds of vector layers; the map looks perfect in QGIS 2.12 Lyon as well as in map composer. None of the layers have scale-dipendent visibility; i have the following ...
1
vote
0answers
29 views

I clip a raster with a vector mask in qgis, the result is correct but its a little bit of, why is this?

On one side the result is "bleeding" over the vector on the other side its more than one raster pixel from the vector on the inside. How to correct this? http://i.imgur.com/d0v6mqt.png ...
1
vote
1answer
50 views

Can I make a multi layers pdf from a mapnik xml?

I am playing with mapnik and trying to export multiple vector files as one pdf with multiple layers. For the moment, my vectors get merged when rendering. Is there a way to keep each vector in a ...
0
votes
0answers
25 views

Spatial Join Points Vector with Raster Dataset using Arcmap

I have a points file of taxi drop off locations and a raster file grid. I am trying to get a count of each point on a raster cell. How do I go about doing that? It is like I am doing a spatial ...
2
votes
0answers
34 views

How can I measure the distance between many polygon features and either another polygon or a line in QGIS?

I often have to manually measure the distance between a single site and other sites around it, but obviously this can get long-winded and I feel like there must be a much more efficient way of doing ...
0
votes
0answers
54 views

Openlayers snapping not working

I am using a vector layer on my map that contains lines like this: var map = new OpenLayers.Map({ div: "map", layers: [ new OpenLayers.Layer.WMS( ...
0
votes
0answers
33 views

Detecting features intersecting with Profile Line using ArcGIS for Desktop?

I am using ArcGIS' (10.2) 'Intersect Line' > 'Create Profile Graph' functions (3D Analyst Toolbar) to get cross sections of lines from a DEM raster. Does anyone know, if there is a similiar ...
2
votes
2answers
103 views

Points that get created in the wrong order when using e.g. QChainage?

I have a polyline layer (road) that I want to use to get a point layer with 1 km between the points. I have tried both 'QChainage' and 'Locate points along lines' to do this. They both work, I get ...
1
vote
0answers
74 views

Using MySQL vector with QGIS?

I have a problem with mysql vector; when I connect to the MySQL table (containing a geometry column), the attribute table is loaded correctly, the map is centered properly but the geometries are not ...
1
vote
0answers
30 views

pgr_nodeNetwork doesn't place new nodes properly

I wanted to use pgr_nodeNetwork tool to split lines where there's no vertex on intersection. The tool doesn't seem to work as expected, though. It doesn't place new nodes right where the two lines ...
1
vote
1answer
104 views

PostGIS: How to dissolve vector data

I have a few scenarios where I need to dissolve vector data, and I'm wondering how to do this using PostGIS. What would the queries look like to perform these operations? Below I'll describe the ...
2
votes
2answers
116 views

Leaflet Vector Layers Not Rendering During FlyTo Animation

In version 1.0 of Leaflet, when using the FlyTo function as per this JSFiddle, is it possible to force vectors to render/ draw as the animation is happening? My current issue is when using the ...
1
vote
1answer
76 views

QGIS shapefile to raster

I have a problem converting a shapefile to raster. I created a point-shapefile using a text-table with some xyz-coordinates. Now I want to convert it into a tiff, where all the areas without values ...
2
votes
1answer
67 views

Styling line layer based on two attributes in QGIS ? (1 discrete and 1 continuous)

I have found a really helpful tutorial to style points based on two attributes. Is it possible to make style lines based on two attributes? I have a shapefile with streets that have two attributes: ...
1
vote
0answers
53 views

Data dependent override on colour and linewidth of line pattern fill not working after upgrade to QGIS 2.12

I have recently upgraded to QGIS 2.12 which has resulted in a problem with one of my projects, whereby the data dependent override of the line width and colour of a line pattern fill and SVG marker ...
1
vote
0answers
19 views

Accessing feature legend style name using QGIS?

I have a vector layer classified by some combination of field values. I want to add a field for each feature, filled with the legend style name of the element. How can I do this? via Function ...