QGIS is a cross-platform GIS application licensed under the GNU General Public License.

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Calculate area of all polygons in a shape file and save it in attribute column “Area” in a python script using QGIS

I have a shape file with about 2000 polygons. I am using QGIS and I need to write a standalone python script which opens the shape file and calculates the area of all polygons separately and outputs ...
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5 views

GRASS init error in QGIS?

Every time when I start my QGIS I see the following message: GRASS init error: Problem in GRASS initialization, GRASS provider and plugin will not work : Module built against version $Revision: ...
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14 views

Can QGIS plot coordinates in Degrees-Minutes format?

I have a .csv file of coordinates that looks like this: Is there a way for QGIS to plot coordinates formatted like this? I've tried Adding a Delimited Text Layer... in QGIS, but do not see any ...
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0answers
12 views

How to install xlw and xlrd libraries on MacOS so that QGIS Python can see them?

I experience a problem with XYtools and need to install Excel libraries for Python. I tried to install them directly from the terminal and it worked on the system, however, how to import them into ...
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0answers
11 views

How to style Geofabrik shapefiles to resemble Open Street Map?

I have downloaded the shapefiles for the UK from http://www.geofabrik.de/data/download.html I have loaded the shapefiles in to QGIS. Could someone please explain to me or point me in the direction of ...
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7 views

Build network based on shortest distance between points

Is there a way to build a network based on the shortest distances between each point of a point layer. I have occurrence data from species (as points) and want to estimate whether there are one or ...
2
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0answers
10 views

Qgis feature count increases at save layer edits

QGIS (2.12.3, running on Windows) increases the feature count of a vector layer when I "save layer edits". If I do the following steps: create a Vector layer (shp file) enable "show feature count" ...
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19 views

How to deal with QGIS Viewshed analysis MemoryError?

I have one SRTM Dem file and one point on it. I'm trying to use the Viewshed Analysis plugin for QGis to calculate the viewsheds from that point. Instead, I get this kind of error: Traceback (most ...
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2answers
24 views

How to select and change only certain (same)values in attributetable in QGIS

I have an attributetable. Spread all over it are numbers like -99999997. I want to replace them by zero (0). There a many columns in which there are such numbers. I have used the expression (an ...
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14 views

I want to build GIS based java application that runs on browse

I am developing one GIS application in java, for that I am using OpenMap and GeoTools libraries(alternatively). These libraries are giving me a frame or say a standalone application, but what I ...
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1answer
26 views

How to create lines to visualize differences between polygon features in PostGIS?

I've a PostGIS table 'polygon_b' with some polygon features. There is also a table 'polygon_a' which contains the same polygons as 'polygon_b' but with minor changes. Now I want to create lines to ...
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8 views

What is the correct format for APA referencing maps produced in QGIS, including data layers?

I need to cite maps produced in QGIS. In addition to my own data, I have used the opensource MapQuest OSM basemap, and a 25m land type data layer obtained from Digimap. I would also like to include ...
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11 views

R gdalUtils::ogrinfo error or very slow

I am pulling WFS data into R and using gdalUtils::ogrinfo to look at the available layer names on a WFS server. Using the same url in QGIS, this is very fast and gives complete information. With ...
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23 views

Insert sequential row and column values automatically into a fishnet dataset

I have a grid that has about 30 rows with approx 15 columns each. I want to label them as A1,A2,B1,B2 etc (Alphabet row, integer is column). Is there any way to do this programatically? There is no ...
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1answer
30 views

QGIS Pre-set CRS/projections missing/unavailable

I am using QGIS 2.0.1 running off of a Ubuntu computer. I have been going through some basic tutorials (http://fossgeo.org/free-qgis-courses/) and have come up against a small and silly little ...
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27 views

Retrieve Google Maps API friendly latitudes and longitudes from shape file polygon

I have a shape file with a polygon in it, and I am trying to the latitudes and longitudes associated with it so I can use them with the Google Maps API. So far I have been working with QGIS Lyon and ...
3
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1answer
27 views

QGIS convert long integers stored as string to integer

I have long integers (11 characters) stored as text in a shapefile that I need to convert to integers, but when I attempt to convert them in the QGIS field calculator, I get the following error: Eval ...
2
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1answer
24 views

Wrong shape display with North_Pole_Azimuthal_Equidistant projection

I need to create a map that displays the breeding and wintering ground of a bird species that has a circular arctic breeding distribution and winters in Africa. The map should lool pretty much like ...
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12 views

How to Avoid that Label Covers Icon?

I'm trying to render both house numbers and icons for sirens on a map in QGIS. Now I have added two layers with siren nodes and building outlines, the siren layer being above the buildings. In the ...
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31 views

Can QGIS 2.8 (Wien) export to Mapserver?

I've tried to export with RT Mapserver Export but it hasn't worked. I'm running >QGIS 2.8.6 on W7 x64. Sorry for my undocumented answer. So, first I install RT Mapserver Export plugin without ...
4
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45 views

QGIS/OGR shp to tab export - crashing Mapinfo due to number format issues

I created a vector grid in QGIS and it exports as SHP -no issues. When I save as tab and try to open the file in MapInfo it crashes. According to ...
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1answer
22 views

Paste a feature from an existing shapefile into a row with null geometry in QGIS

If I have an existing row in my PostGIS database with NULL geometry, is it possible to select a feature from another layer in QGIS, and paste that into the empty geometry column for the PostGIS row?
2
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1answer
58 views

Strange names of swedish cities [duplicate]

I got a GIS Data-set for swedish cities. The problem is that they have strange names such as: Trädet Jäla Mjönäs Älmhult Did someone have the samoe problems? I think "ö" for instance mean ...
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1answer
26 views

QGIS: Buffer around external border of a country based on federal state borders

based on the question "QGIS: several layers - query" I have an additional question: With "join attributes by location" I got a layer that constist of the city names with the corresponding ferdale ...
3
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2answers
36 views

Unexpected behaviour using ST_Equals() with QGIS

Let's say there is a table 'polygon_a' and a table 'polygon_b'. Each table contains three polygon features. The polygon features are spatially equal. CREATE TABLE polygon_a ( gid serial NOT NULL, ...
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2answers
40 views

How to add state polygon information to a city point?

I have the following layers: Country border federal state borders cities (located as points) I would need the following result file (txt or csv..): A column with the name of the city and another ...
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10 views

QGIS graphical modeler: how to automatically enter parameters in r.drain.coordinate tool

i am carrying out a cost least path analysis and i am using QGIS. The processing tools i am using are: r.cost.full and then r.drain.coordinate Considering i have more than 1000 layer to process ...
3
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30 views

qgis2web problem with lots of data

A few month ago I was able to make a polygon map of population: http://supermap.hostei.com Today I opened the same QGIS project and tried qgis2web again. The plugin interface had responding ...
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3answers
167 views

How to select specific rows of polygons from a grid in QGIS?

I have a polygon layer. I would like to select every second row of the polygons but not manually. Is there an expression to select every second row as seen on the picture with Select by expression in ...
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0answers
30 views

Problem in polygon division using the union tool from QGIS

I am trying to overlay two polygon layers using the union tool from QGIS, to then compute the areas from the resulting polygons. However, in the resulting layer some polygons are not divided as ...
4
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21 views

Thematic map exported using QGIS2Web is extremely laggy

I have made a world thematic map and added layers of data for creating graduated color scheme on the country level. I need a interactive map as an output which shows values when user hover over any ...
4
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1answer
70 views

Problem Editing a Vector Layer QGIS

I have a vector layer which I need to load and edit (add several attribute columns). I am doing this without opening QGIS, so within a python script. I have the following piece of code for the layer ...
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25 views

Write userID to field automatically every time an object is edited

Currently every user has to put his/her useriD in a field after every change made to an object in the database. This takes time and can be forgotten easily. Is there a SQL-Command giving back the ...
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11 views

Open Street Map Base Map on QField

I am using QField on an Android tablet, I would like to know if I could use a web mapping service like open street map as a base map. Without having the actual file stored on the tablet?
3
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2answers
125 views

How to create in QGIS shapefile a field that automatically returns the current date

I'm digitizing a shapefile in QGIS and I need to create a field that returns automatically the current date.
1
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1answer
16 views

Is there a possibility to simply display the next element on a layer?

I have to check all the elements on a layer and I'm looking for an easy way to go through all of them. One option would be to open the attribute table and just always click on the next line and then ...
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0answers
19 views

Python error when using r.reclass on raster with no CRS

I have a set of GRID data (directory of .adf files) that I'm trying to reclassify in QGIS. I'm using the GRASS r.reclass function to try to reclassify the layers, but GRASS keeps failing and ...
2
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1answer
18 views

Creating groups containing slopes of a specific range

I have a basic knowledge of QGIS and can do everything I need to do to achieve my requirements except the following. I'm trying to graphically show areas of land that contain a set of specific slope ...
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2answers
35 views

Enabling preview in QGIS recent projects?

after installing qgis on win 10 I am missing the map-preview in the recent projects window as I had under win7(see screenshot). where is the setting to enable this?
4
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1answer
57 views

Which is better for measuring actual ground elevation, NED or SRTM?

I know that NED DEM layers are created using mainly Lidar point clouds and that the SRTM derives its data from shuttle-based radar. I have both of these loaded into QGIS and can see that over my study ...
4
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2answers
45 views

Retrieve available PostGIS connections in PyQGIS

Can I retrieve the available connections to PostGIS databases in PyQGIS? I would like to provide a list of available db-connections, and subsequently a list of tables within the ui of my plugin. I ...
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23 views

Calculate obstacle accountability area in QGIS

Still being new to the whole GIS world, I am trying to calculate a regulatory takeoff obstacle accountability area for a given runway. For my case, this is defined as an area as follows. At the start ...
2
votes
1answer
57 views

How to create a shapefile from xy in .csv file?

I find many difficult to create a new shapefile in a new project following those steps. I think the .csv file is correct (there are only: ID, X coord, Y coord) but when I would create the shapefile ...
2
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0answers
25 views

Qgis slow on loading project

Is there any work around to mitigate the amount of time QGIS takes when loading projects that have large tables from postgis layers . I have tried to turn off this large layers so they are not in use ...
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1answer
44 views

QGIS Shapefile edited by multiple users

I have a Vector layer containing 36000+ line Objects with a large number of attributes that is currently saved as Shapefile on a server (local network). Multiple users access and edit this Layer ...
3
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1answer
51 views

Update column in .shp from .tab with QGIS

Is it possible to perform in QGIS an "update column" on a .shp table with data from a MapInfo.tab having one field apparently in common? One of the greatest uses of QGIS (for me) is the availability ...
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1answer
18 views

Raster update error when saving heatmap in QGIS

I am using QGIS and I recently added a delimited layer and all my coordinates appear fine , however when I add a heatmap I get the error "Raster update error: Could not open the created raster for ...
2
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2answers
47 views

Icon for plugins in own repository

Does anyone know if there is an opportunity to add icons for your own plug-in in its own repository? like this not like this with green puzzle other illustration I spied on how to implement ...
2
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1answer
35 views

Is there a way to create a presence/absence matrix of polygons per cell in a grid using qGIS?

I'm working in QGIS with species distribution polygons and I want to know how many cells in a grid does the polygon overlap. I've tried creating random points within the polygon and then used ...
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0answers
33 views

QGIS becomes unresponsive when adding new vector layers?

QGIS suddenly won't allow addition of vector layers when running on PC (Lyon 2.12.1). I've reinstalled it, no help. I've recently changed to Windows 10 from 7, otherwise nothing much has changed on ...