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

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33 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 ...
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1answer
115 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 ...
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2answers
136 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 ...
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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
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1answer
72 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: ...
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55 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 ...
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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 ...
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0answers
27 views

How does qgis render vector layer on screen ? How can I do the same in a mobile device

Can you please tell me how does qgis software render the vector layers on the screen. I have a geojson file and I need to map its contents on the screen just like qgis does but without using base map ...
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1answer
100 views

Combine digital elevation model (DEM) with point layer (QGIS)

I have two layers: The first one is a digital elevation model (DEM) as GeoTiff. The second is a point vector layer (start and end of street segments). What I want to do: Add elevation information ...
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0answers
35 views

Create polygon layer from point data with number attribute where polygon encloses n% of point data attribute value in QGIS [closed]

I have two sets of data, one is the CodePoint Open with the location of all of the uk postcodes, the second is from online form data from which I've extracted the postcode and telephone area code, and ...
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2answers
207 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 ...
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0answers
44 views

Distance Analysis from single point to multiple points on vector layers

Is it possible to do the following in QGIS: Create a text file that plots the distance from a single point (stored in one layer) and multiple points (stored in another layer). I have tried to use ...
2
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0answers
68 views

Error trying to save vectorfile in QGIS 2.10?

I'm trying to save some changes I made in a vector file (polygons) in QGIS 2.10. The file contains properties and I want to merge two of them into one. I toggled and selected the two and then pressed ...
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2answers
29 views

QGIS: Class boundaries

I have seen that people already had issues about overlapping class boundaries with the classification of graduated vector data. I am wondering if there is somewhere written in the documentation if ...
2
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2answers
117 views

Convert point to line

A little background: I recently completed a long bike trip and used a GPS to gather data during the ride, including average speed and elevation loss/gain. I imported the data into QGIS. These data ...
2
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1answer
276 views

Cannot get Openlayers 3 WFS vector layer from Geoserver

I read a book about Openlayers 3 and I guess its about an older Openlayers version because it mentions a ol.source.ServerVector vector source for getting WFS layers from a server. In the latest ...
5
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1answer
171 views

Create shapefile of raster outline using python

I want to create a single bounding shapefile polygon of valid pixels in raster data (GeoTIFF) using python. I need something efficient as I need to do this for hundreds of rasters. I had thought of ...
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0answers
59 views

Alternatives to QGIS difference tool

I have a very large shapefile of building polygons and a shapefile of the country they reside in (England). The building shapefile was built by merging 94 smaller shapefiles. Both files have the same ...
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2answers
147 views

Selecting Specific Elevation Areas Contiguous to the Coastline for Coastal Flood Mapping

This is less a problem than an inquiry into a better way of doing something. I am curious how people might go about selecting, say, all areas less than or equal to 10 feet (from a DEM) that are ...
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1answer
174 views

QGIS elevation and relief shade

I am trying to generate a map with terrain and elevation in QGIS and as a beginner I have followed tutorials on how to generate contours and hill shades succesfully. However, I don't know what are the ...
2
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1answer
86 views

Most recent tectonic plate data

What is the latest update to the positions of the tectonic plates? Does anyone have a most up-to-date shapefile or vector of the tectonic plates?
2
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1answer
22 views

Multi-string data-set without z layer, applying ordinal values as a workaround

I'm new to GIS and have been learning a lot over the last few weeks, however, I've finally come to a point where I could use some help. I'm working with the pdx_streets data-set from ...
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0answers
91 views

Clipping polygon using QGIS?

I want to clip a polygon using Qgis "clip" tool. The problem is that the resulting polygon presents areas that where not clipped off. The first screenshot shows the layer I want to clip using the ...
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1answer
87 views

how do i create OGRSpatialReference from raster file's georeference C++

I want to create .shp file using ogr with georeference based on my raster file, so i create an ogr layer using CreateLayer( "point_out", NULL, wkbPoint, NULL ); i want to set the OGRSpatialReference ...
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29 views

Plunge and trend of vector lines in ArcGIS for Desktop?

Does anyone know how to extract dip and dip-direction (or trend and plunge; dip and dip direction define the spatial orientation of planes, trend and plunge of linear elements) data from a series of ...
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1answer
64 views

Creating Polygon from a Raster

I have a Raster representing climate data. I converted the raster to vector using the tool raster to vector (Arc Map) and i got something like below: Can somebody help me out by guiding me in actual ...
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1answer
128 views

How to merge vector buildings height layer with raster DEM to get solar maps in r.sun in Grass GIS?

Welcome, this is my first post. I have vector layer with buildings heights and vector/raster DEM file. I need to create solar maps with sun radiance values on the roof (and on surface, ofc). I am ...
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0answers
58 views

How do I create a map of addresses?

This is a tricky one. A little context first: Bentiu wiki page: https://en.wikipedia.org/wiki/Bentiu + OSM map of Bentiu refugee camp, South Sudan: http://www.openstreetmap.org/#map=16/9.3314/29.7920 ...
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2answers
103 views

Splitting vector file by date (year) but column containing dates in Day/Month/Year format?

I am using national accident data in QGIS and quite frankly the dataset is huge as it contains every recorded accident between 2005 and 2014. I've split datasets by field for a number of vector ...
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1answer
35 views

Polygon to multiline object in ArcMap?

Is there a possibility to create a multiline object from polygon object contours in ArcMap? I found that Edit toolbar allows to create polygons from other shapes, but I couldn't find anywhere an ...
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0answers
16 views

Arrangement of vectors and matrix in text file?

My ASCII file has a vector of latitudes, and the indices of those latitude values tie latitude values to the data sharing the same index. That is, if given: latitude[x=0,1,2,3] = 10, 20, 30, 40 ...
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1answer
93 views

Viewshed plugin in QGIS doesnt work

I loaded DEM and Point data and as a result i just got black raster (still black after calculation). If I click intervisibility I cant see it like if line data is not there. I tried changing meters, ...
3
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1answer
67 views

Why is QGIS only one label rendering at a time?

I'm new to QGIS, but I'm experiencing what I think is a bug. When I load the qgis_sample_data landcover raster and lakes vector layers, then enable labels for NAMES on that layer, I can only ever ...
2
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1answer
354 views

Shapefile/vector layer not appearing in QGIS

I have a shapefile (calling it 'new.shp' for discussion's sake) that won't show up with other layers. If a fresh file is started and I bring in new.shp, it will appear, but any other layers imported ...
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1answer
39 views

Query across layers of SHP files?

I would like to query features from a SHP vector that intersect with features from another vector. Pseudocode: "Name" IS intersects( countries) How would be the valid query composed?
2
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3answers
92 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 ...
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1answer
218 views

Vector layer visibility using min/maxResolution is not working in Openlayers 2

I am using OpenLayers 2 and Geoserver. I have a few WFS layers and an OpenStreetMap as a Baselayer. I want to change the vector layers' visibility at certain zoom levels, by using min/maxScale or ...
1
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1answer
68 views

reading GRASS vector map in python

I know similar questions have been asked several times, but none of the solutions seems suitable for my problem or don't work.. I computed flowlines using the r.flow tool from GRASS GIS, then I ...
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2answers
151 views

QGIS 2.10, csv points to vector grid

I have a series of point data from a .csv file that I would like to display as a heatmap raster, the .csv data have various attributes with them and I would like to adjust the color ramp based on ...
1
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1answer
91 views

Retrieve MapBox tiles in vector format rather than raster

I am using MapBox and I would like to render my tiles directly from vector format but I was not able to find how to retrieve the tiles in vector format rather than bitmap. So, when I use this url: ...
0
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1answer
112 views

Is QGIS Server working like this?

On CentOS 7 I have QGIS Server and QGIS Desktop installed. In QGIS Desktop I created a project with raster and vector data and saved it in a ".qgs" file. Then I copied the file in ...
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0answers
7 views

Sky View Factor of building roofs => Vector algorithm [duplicate]

I'm currently working on a project in which I'm trying to assess the SkyViewFactor of a given roof using building vector data. I've already managed to build a process based on vector rasterization ...
1
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1answer
77 views

QGIS Vector Data with blank attribute tables

I have vector data shapefiles for Manitoba, but there is no names in the attribute tables. It seems Manitoba is still working on their attribute data. Is there a shapefile I can download to get these ...
1
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1answer
50 views

Intersection of two vector tables data in postgresql

I have satellite raster data that is converted into pixels using CREATE TABLE gtru_tile_pix AS SELECT (ST_PixelAsPolygons(rast)).val, (ST_PixelAsPolygons(rast)).geom FROM gtru_tile_raster; ...
2
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0answers
103 views

How to tell if map service is fully vector or raster?

sorry if this is a duplicate, but I was wondering how to tell if a map service (in web browser) is vector based or raster based? What I think to understood so far is that Google Maps for example is ...
4
votes
1answer
99 views

Creating shapefiles using textfiles in QGIS

I have a shapefile in QGIS which has polygons in it . There are several other attributes for each feature . I want to add another attribute to each feature . The value for this attribute is available ...
0
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2answers
86 views

Layered world map

First off I just want to say that I am NOT sure if this is the correct place to ask this question; So if it is not, please direct me to the correct exchange. So for the question: I am looking for a ...
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0answers
58 views

Aggregate/merge data upon insert into PostGIS (via gdal)

I am working on a project where I take a large raster file (1.5GB+), put it through a number of image-processing operations, and finally convert it to vector data. Being that the raster is large, I am ...
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0answers
22 views

How to make coincident a vector layer and a bitmap constructed from Google map tiles using programming

I can make a bitmap file from tiles that I receive from Google map using X_Tile,Y_Tile and Google map zoom parameters successfully.First I use a vector layer to find map extent in UTM,so I have ...
1
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2answers
48 views

Building error with QgsVectorFileWriter

I am working with qgis api c++ 2.8.2, in c++/QT 4.5 I try to save my List of QgsField but I have the error message : no matching for call to 'QgsVectorFileWriter' I took the sample from here : ...