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Questions tagged [qgis]

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

1
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0answers
31 views

How to update map canvas in QGIS 3.4 Print Composer

I'm using QGIS 3.4. Print Composer. I created a print composer template with a map canvas. I want the map extend to be refreshed every time I open the template and also update it manually with a ...
0
votes
0answers
29 views

Geoserver+GDAL+OSGEO4W ECW support

I am trying to install the GDAL plugin for Geoserver on machines which have windows 7 and 10. both machines had a previously installed version of OSGeo4W. I followed all the instructions in the ...
1
vote
1answer
24 views

Default value not updating on “Add Part”

I have a default value setup on a column in QGIS to calculate the area of a polygon. I also checked "Apply default value on update". This works if I add a polygon or change the vertexes. If I add a ...
1
vote
0answers
35 views

Storing custom QGIS form in PostgreSQL

I would like to store my custom .ui form in the QGIS style saved in PostgreSQL, so I can load it within the layer. The option is here when you save the style, but I can't see it stored on the ...
0
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2answers
60 views

Seeking list of spatial functions available in PostGIS but unavailable in Spatialite?

It seems like most of the classic spatial function available in PostGIS (i.e. ST_Buffer) are usable with Spatialite, but some others don't seem to be supported in Spatialite (i.e.: no such functions: ...
1
vote
1answer
47 views

Displaying overlapping points in QGIS?

I am trying to produce a map of last years emergency responses in my area in 2018. I am entering a CSV file into QGIS which is working fine. The addresses and Lat and Long have been verified. I ...
1
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0answers
35 views

QGIS fails to generate requested number of random points

Does anyone have any ideas what might be blocking this process? The layer has thousands of polygons totalling hundreds of thousands of square metres, but when asked to locate 140 random points even ...
0
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0answers
24 views

Function in R to get difference between two sets of polygons comparable in speed to QGIS

I have two very large polygon shapefiles for which I need to calculate the difference between the two shapefiles. One is a shapefile of forest polygons, the other is a shapefile of road polygons. I ...
2
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0answers
23 views

Error when clipping raster in QGIS

I have done it many times (clipping a raster with a polygon layer or by extension) but today I got an error for the first time and I don't know how to solve it. I am always using the same type of ...
0
votes
2answers
29 views

Shapes shift over Bing images on QGIS when scolling the screen

Using QGIS 3.4.3, the shape files created don't fit with Bing aerial plugin only on the right side of the screen, on the other hand, for the same screen, the left side looks ok. When I move the non ...
0
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0answers
36 views

Looping through Clip Raster By Mask function

I created a script to loop through the Clip Raster By Mask function. I assign my personal files to the variables and use a nested for loop to iterate through the feature ID numbers in my selected ...
0
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0answers
24 views

How can I change the elevation of a lake on a DEM so I show the lake bottom contours?

I'm studying the drainage of a lake and I have a DEM of the lake and the surrounding area. I already identified the shorelines of ancient lake levels at higher elevations, but I would like to keep ...
0
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0answers
33 views

Erroneous contour polygons in QGIS 3

I have a global DEM and try to calculate contour polygons for 4 different heights in QGIS. In the first image below, you can see the colored DEM (white = lowest; yellow = higher; orange = highest) as ...
1
vote
1answer
54 views

How can I see comma in attribute table?

I want to see comma instead off points in my attribute table. What happens is: When I import TXT or CSV there´s an option to use comma as decimal delimiter but after the importation I only see points ...
-1
votes
1answer
31 views

How can I create RGB composite from a set of rasters

I have a lot of 4 bands rasters with bands: blue-green-red-NIR, and I need to create 3 bands rasters with bands: red-green-blue. How I can automizate this process using QGIS?
1
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1answer
30 views

Force a minimum value in a color ramp classes in QGIS 3.4.1

I am trying to apply a color ramp to a shape using percentage values where red would be low and green would be high. The data ranges from 74% to 100%, but I need the minimum value to be 0%, so that ...
-2
votes
1answer
26 views

How do I filter 4 features from a vector shape file to create a new layer to perform buffer, intersection and union on it, in QGIS 2.18?

From a dataset that contains points of interest defined by type of object with 4 different features, I am trying to distinguish the features to perform different analysis. Thought I had to filter the ...
1
vote
2answers
180 views

Zooming/panning map in QGIS layout independently from frame?

I am coming from ArcMap. Working in the layout view, I had buttons to zoom/pan data and other buttons to zoom/pan the view itself. In QGIS, I can't seem to be able to achieve this. The only buttons I ...
0
votes
0answers
32 views

Can't open WMS that worked before

I've been trying to access a several WMS servers in order to visualize imagery on my QGIS but when I put the URL on the searcher no results are given, as if there were no WMS server with such URL . I'...
1
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1answer
41 views

Is there any plugin that plots a profile from point survey data in QGIS 3

I used to work with the plugin ProfileFromPoints, but it is not avaible 8or updated) in Qgis 3. I wonder if there is another one which does the same or if there is an easy (foolproof) way to use the ...
0
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0answers
21 views

How to edit a legend for WMS map in layout

I'm working on a project in QGIS and I'm trying to edit a legend for a WMS map in a layout (see pic below). From what I read the legends for WMS maps are provided as images and therefore they cannot ...
-2
votes
1answer
40 views

Shortest path using line layer QGIS

I have a layer consisting of aprox. 20k lines What i want to do: In Qgis I want to be able to enter a start point and a end point. Preferably with street addresses and in second hand with ...
0
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0answers
35 views

Using a spatial query to filter the atlas pages in QGIS

I would need to create an atlas of all the map sheets (red rectangles) that refer to a specific municipal territory (for example the selected yellow polygon) as in the image. The atlas coverage layer ...
1
vote
1answer
28 views

Trying to add lat long points to a map, not getting an ok button

I add "Data Source Manager" then "Delimited Text" and i select the x y and coordinate system but there is no OK button? just add and close add just restarts the process. how do i get the ok button?
4
votes
1answer
77 views

Create Line From Points

I have this NDVI image of eucalyptus trees. I've already been able to isolate the trees and extract the location. Then I created the delaunay triangulation, turned it into lines, and then exploded to ...
2
votes
1answer
27 views

Calculating Area with GSSURGO vector data

I'm attempting to calculate acreage of the various "prime farmland" classifications in the GSSURGO dataset for the Omaha Reservation in Nebraska using QGIS but when I sum the total it's about 86 times ...
2
votes
1answer
34 views

Create a polygon with a list of coordinates gave by QInputDialog in pyqgis console

I have a problem when i run this script. It gives me: TypeError: QgsGeometry.fromPolygon(unknown-type): argument 1 has unexpected type 'list' Here is my code: # -*- coding: cp1252 -*- from qgis....
1
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0answers
25 views

How to enable and change Symbol levels programmatically? [closed]

I have a vectorlayer which contains some features and I'm having problems representing them because they are being overlapped with an incorrect order. They have a field that numerate each feature so ...
0
votes
0answers
27 views

Is it possible to do a visibility analysis and create a 3d - cone as a result in ArcGIS?

I have a digital surface model of a region and the coordinates and height of an observer point and need to do a 3d - visibility analysis for this point. However, as a result I would need a ...
0
votes
1answer
50 views

How to give a table some geometry from a view on QGIS using a join?

So basically I've got this static table that people update information Then I need it to give it some geometry from a view table. This geometry is dynamic, that's why can't just make a new geom ...
0
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0answers
34 views

QGIS 3 - Variables in rule-based rendering?

I'll try and lay this out clearly, I have most of it covered, but there's a very specific thing I'm looking for in the rules - whether or not it can be done and if so, how? Key things I have done and/...
3
votes
1answer
48 views

Exponential notation in attribute table QGIS

I've imported a spreadsheet from excel, all my spreadsheet data is formated as "number" inside it. When I import it in QGIS, it changes to exponential notation as shown in the image below. Is there a ...
1
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0answers
31 views

Dataset description AREA_OR_POINT

What are the differences between these two options in satellite image metadata?
0
votes
1answer
35 views

Calculating area in the attribute field of a QGIS 3.4.3 project with multiple CRS

The area calculations in my project derived from the attribute field show values way below actual area, because the attribute field assumes the project CRS (EPSG:3857). However, this CRS should remain ...
3
votes
1answer
104 views

Merging lines (with and with no overlaps) in QGIS

I have two layers ("Layer_1" and "Layer_2") of lines where they sometimes overlap and follow each other for a bit and then takes another route (see the image below). "Layer_1": Red line "Layer_2": ...
0
votes
1answer
33 views

GQGIS 3.2 Join Attributes from Layer Limitation?

I want to join two txt tables as a layer in QGis 3.2. In eralier versions (2.12) works to join one of the tabel more times to the other table. Now in the version 3.2 i can join only one time. The ...
0
votes
1answer
29 views

Unscramble RGB raster - 4D interpolation/lookup

I have a 4-band raster image (RGB), downloaded from a WMS, representing clay content of topsoil ranging from brown (high clay content) to yellow (low clay content). The 4th band is alpha-band, with ...
2
votes
0answers
67 views

Using Google BigQuery GIS table as a data source to QGIS

Google BigQuery recently added GIS functionality (still in beta), see here. I have a dataset in BigQuery that I would like to use as a data source in QGIS - much the same way as I would do with a ...
1
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0answers
22 views

QGIS r.reclass batch processing error

I am reclassifying 43 rasters in Grass r.reclass function and am getting the following error: Processing algorithm 1/43… Algorithm r.reclass starting… Input parameters: {'GRASS_RASTER_FORMAT_META': ''...
2
votes
3answers
68 views

Merging layers into one- QGIS

I have numerous population layers for the Baltic Sea. In the attribute table of each layer, I have population densities, name of towns etc, all the same geometry (points). I'd like to merge the layers ...
1
vote
1answer
28 views

How to ensure screenshot from Bing Aerial matches QGIS Bing Satellite?

I am looking to work from a screenshot of Bing Aerial that is georeferenced in relation to Bing Satellite from the QuickMapServices plugin in QGIS 3.4.3. I have matched the scale from the Bing ...
2
votes
3answers
94 views

Nesting project file name into layout in QGIS

Is there any way to automatically take information from the project file name into several boxes on a layout in QGIS? For example, if I had a file name of "185.005R1 - Geology Map.qgz" how could I ...
1
vote
1answer
45 views

Export MultiPolygon data as WKT from QGIS 3

I have the polygon data for the city of Kamloops in QGIS 3. When I try to copy features of this polygon and try to paste it over here: https://arthur-e.github.io/Wicket/sandbox-gmaps3.html I don't get ...
0
votes
0answers
16 views

Problems with raster to point operation in QGis 2.18.17

I tried to make points of IDW or Kriging interpolation. From point csv-file I made .asc raster file, then I tried to make "raster value to points".At first QGIS wrote me about the error: ascii' ...
0
votes
1answer
43 views

Can I programmatically output the same map with different shp files?

I have 39 different .shp files of the same locations but different data values and I need to output a map for each of them. Is there a way to build a map template and then run a process that will ...
0
votes
1answer
53 views

Reclassify and combine rasters in QGIS?

I have a vector layer containing watercourse location which I have rasterized. I also have a DEM containing elevation data for the region in which the watercourses are located. I would like to ...
1
vote
2answers
49 views

How can I check if two attributes match between a point and the area within which the point is located? in QGIS

I would like to verify a geocoding process. I have used googles API and have geocoded about 35.000 adresses within Austria. By inspecting the locations it is obvious that a few lie outside of Austria (...
2
votes
0answers
50 views

Problems with latitude/longitude grid in QGIS 2

I try to produce a thematic map in QGIS, like this one done in MapInfo: I want to do this in QGIS. I work in projection "Albers-Siberia" projection ( PROJ.4: +proj=aea +lat_1=52 +lat_2=64 +lat_0=0 +...
0
votes
1answer
32 views

QGIS Print composer using margin and scale

When using the Atlas feature in the print composer is there any way of using both the Margin around feature and a defined scale?
2
votes
1answer
42 views

Method to convert all 'overlapping' points to exact same geometry in QGIS 3.4

I have a point vector layer with approximately 2.5 million points, many of which share the same or a very similar geometry (within 1 m of each other). I would like to know if I can bulk amend the ...