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

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70 views

joining polylines on geometry and attribute

I have dowloaded an Open street Map shapefile containing streets and their attributes, for my whole country. I have qgis and spatialite_gui and a very basic understanding of SQL The problem I have is ...
3
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1answer
665 views

Help with scripts for processing raster files with the raster calculator in QGIS

I am trying to process some raster files using python scripts in Qgis 2.20, and I have been having trouble finding any documentation on using raster calculator in scripts being run in the processing ...
1
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2answers
310 views

Create a common scale for different raster layers in GRASS, SAGA or QGIS

I have a number of layers that represent the temperature variability of the water in a lake. They have been generated trough interpolation and have different values as they represent temperatures ...
0
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1answer
196 views

Globe on my Qgis doesn't work.

OS : osx 10.9.2 * I just operated a clean osx installation. Globe have never worked since I started to learn QGIS. When I tried globe, it terminated QGIS then a message(see below) occurred. Any ...
2
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1answer
294 views

Problem installing QGIS Valmeira on Windows 7 Professional 64-bit

I have been having trouble installing QGIS Valmeira on Windows 7 Professional with SP1. When I installed to the default directory C:\Program Files\QGIS Valmiera\, many of the predefined coordinate ...
3
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1answer
2k views

Parameter values to create a vector grid with 1km x 1km cells?

I created a shapefile from WKT in QGIS using the values from this link. I want to create a vector grid with 1kmx1km cells but I can't figure out what values need to be set for the X and Y parameters. ...
2
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1answer
55 views

In what ways has QGIS 2.x API changed making Plugin Builder Tutorial invalid?

I am working on the QGIS workshop Tutorial for QGIS Plugin Builder and notice that it is for QGIS 1.1. As this seems like a popular tutorial, in general, what are some areas of this tutorial that need ...
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1answer
85 views

Identifying streets of same name where split by osm

I have a large map of every street in the country. This is a vector layer in QGIS many streets are split by OSM , IE have a different OSM ID yet the street has the same name. Often these streets are ...
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1answer
36 views

Is there a way to edit the host name of Postgis layer?

Recently I change my server to a remote host. That's means all my work there I used Postgis layers, the host name at the source is set to 'localhost' and I need to change to 'remotehostname'. The ...
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2answers
232 views

Have I created a valid Spatialite database?

I didn't manage to find the better way to populate the exisiting Spatialite database with new computed data than just creating new columns and filling them in the Python script. You can see that the ...
2
votes
1answer
87 views

Why this two datasets don't match?

I have a postGIS database in SRS 4326 (WGS84) with several Europe layers working well, but when I load a shapefile projected to the same SRS with QGIS, the layers don't match. To explain it better ...
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0answers
21 views

Can QGIS2 refresh layers without the need to reclassify each layer individually?

I have a set of layers which I'd like to have refreshed each time I open QGIS2.2.0 (Windows 7). Each of 14 layers (polygons) is linked via a join to a csv file with no geometry. The layer displays a ...
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0answers
313 views

Mapnik: GeoTIFF flipped (mirrored vertically)

I generated a GeoTiff using the QGIS HeatMap plugin and want to render it on top of some OSM data. The problem is that the raster gets rendered upside-down in the output. Can someone point me in the ...
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0answers
171 views

qGIS' Database Manager “Load as New Layer” Option Not Working

I'm trying to visualize some of my database queries on qGIS. I run a valid SQL query which returns a subset of my table that should be easily loaded as a layer. I then check "Load as new layer," ...
2
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2answers
575 views

Update/refresh edited PostGIS table in QGIS

I imported a PostGIS table (with geometry) from my PostgreSQL database as a layer in QGIS. Later, I edited the table using PostgreSQL UPDATE commands. Is there a way to quickly update (like a refresh ...
1
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1answer
609 views

How to add the attributes of selected features to my new layer in pyqgis

I am trying to create a layer from the selected points coordinates. I am drawing a circle to the coordinate of selected points. I also need to add initial attributes of my selected features to my new ...
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0answers
47 views

Problems with projections in QGIS 2.2 on a Windows Vista? [duplicate]

I use QGIS 2.2 on Windows 8, and the same QGIS 2.2 has been installed on a computer with Windows Vista. On the Windows 8 everything works just fine, but something is wrong on the Windows Vista. All ...
6
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1answer
5k views

Draw lines from points in QGIS

(I found here similar questions but they all reffer to ESRI's programs, and I use QGIS) I have a point layer and need to draw a line passing through or in the vicinity of the points (up to 0.5m ...
0
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1answer
418 views

How to change polygon display/symbol properties in QGIS while digitizing?

I have two questions. It would be great if anyone help me to sort this out. Thanks in advance 1) While capturing a polygon in QGIS, how to remove the red - shade - sort of thing..... ? 2)Though the ...
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0answers
305 views

How do I smooth edges of polygons in QGIS?

Is there a built in function or plugin I can use to achieve smooth lines for my polygons instead of the blocky ones I have now?
2
votes
1answer
47 views

How do I make this into a working CRS in ArcGIS?

+proj=tmerc +lat_0=0 +lon_0=-114 +k=0.9999 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs I have this text string which I successfully used to project data in QGIS. How do I use ...
3
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2answers
198 views

Why do I get an empty shapefile when converting this KMZ in QGIS?

I have downloaded a KMZ file containing global elevation information. I have tried to convert the data to a shapefile using qgis (save as shape option) and using the zonum solutions website but both ...
3
votes
1answer
341 views

Converting QGIS Labels to a Polygon Shapefile

I am trying to create an annotation feature from labels and then export this out as a polygon shapefile (the resulting shapefile can then be loaded into ArcGIS online to basically have labels without ...
2
votes
2answers
465 views

Conversion of point grid to a raster with open source tools (Gdal, QGIS …)

I'm looking to do something which seem simple to me, but I haven't found a solution since 2 days I looked for. I've got a Postgis DB with lot of points (WGS84) spaced of 100 meters which cover a ...
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0answers
129 views

Multiparts and Multigeometries: checking for multigeometries with PyQGIS?

I have been working with PyQGIS and writing a small script to check whether the layers I have in the MapCanvas have geometries of type "MultiXX" because I want to run the "Multipart to Singleparts" ...
2
votes
2answers
71 views

How to fix “The selected file already seems to have a world file!” when image hasn't been georeferenced before?

I am georeferencing historical aerials from 1988 in QGIS 2.2.0. Sometimes it works perfectly and other times after I have places my points and start the georeferencer a window pops up saying: "The ...
0
votes
1answer
235 views

How to create input data for the LRS plugin from an excel table without coordinates?

I'm working with QGIS 2.2.0. I want to add a shapefile from an excel file that has informations I want to use in the LRS plugin. The excel file has no geographic information. Every time I try to save ...
0
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1answer
129 views

How to join information from an excel table to a road feature in QGIS?

I'm working with GQIS 2.2.0 Valmiera. I've made a shapefile of a road that consists in a single line. Now I want to add information that I have in an excel table about several point in the road. How ...
2
votes
1answer
522 views

Why does QGIS 2.2 Atlas not work?

I have problem with atlas generation in QGIS 2.2. I'd like to export pdf map with 2 maps window and use coverage layer function. Atlas doesn't iterate across the features in coverage layer. First ...
-1
votes
1answer
59 views

Can QGIS alone can be used without installing grass?

can QGIS alone can be used without installing grass? i want to use functions of grass and i am not interested to create mapset and all. just with raster and vector files, i want to study temporal ...
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1answer
139 views

How to calculate the area of an ellipse on the earth's surface using Python?

I have a dataset consisting of GPS coordinates. I use a clustering algorithm to generate a two dimensional Gaussian for me. The Gaussian takes the shape of an ellipse if visualized on the map. ...
0
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1answer
221 views

QGis: scripting the map rendering (multiple similar maps from one shapefile)

I would like to ask for advice on creating a Python script that will provide the opportunity to render a plenty of similar maps (with the same extent, projection, layout, color scheme and composition, ...
1
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1answer
3k views

MSSQL Connection settings for QGIS

OK first lets get the blond elements out of the way- I'm not asking for how I connect to my actual database. What I'm asking for is an example or screen shot of the entries required when setting up a ...
0
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1answer
69 views

Producing gradients between shapefiles and using original boundarys as isoclines (lines)

to produce a bathmertical map of a river bed I draw shapefiles showing the different depths based on satellite images taken during different tidal levels (deepest, 2nd deepest, 3rd deepest, shore ...
2
votes
2answers
118 views

What's the use of the buffer function in field calculator?

I'm trying to find out how the buffer command in the filed calculator works. I tried to create a new field to my point shapefile (integer) with the following: buffer ($geometry, 100) but no ...
0
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1answer
129 views

QGIS map tip / label showing a table

I have a MSSQQL Spatiatal layer with Point data (borehole locations, pointID) and a joint table lithology (soil info per borehole, pointID, depth from, depth to, constituent) Is there a way to use ...
0
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1answer
62 views

QGIS 2.2 Atlas - Blank Export

I've got a map laid out how I want it in QGIS 2.2, using the "Atlas Generation" feature. When I preview the atlas, all 7 pages look proper and seem to work fine. However, I cannot export them to any ...
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0answers
28 views

Can a joined-layer have its attribute changed depending on what layers are selected/deselected?

Using QGIS, I have a polygon-grid layer which covers everything, Layer_All joined with 2 other grid layers: Layer_1 and Layer_2, both of which intersect at various points. I would like Layer_All to ...
4
votes
1answer
416 views

QGIS - move a point object to specific coordinate

Is there a way of select an object (point, polygon) and move it to a specific coordinate (manually inserted)? (with Numerical Digitize plugin can not make a move of the object but rather it creates ...
2
votes
0answers
130 views

Sorting points to flight path route

Original question: I would like to sort my points in QGIS. See image Restated question: The grid tool currently numbers by starting at R1C1 and going to R1Cx, then R2C1 to R2Cx. How do I number the ...
0
votes
2answers
72 views

Rasterization in different bands

I have a set of vector based shape files, representing different types of ground coverage in a city (for ex: roads, buildings, open field,...). For the algorithm that I want to run on it, I need just ...
1
vote
1answer
235 views

How to set the output extents of rasterization in QGIS

I am trying to rasterize a bunch of vector based shape files in QGIS. All these files are covering certain types of ground use in a city (houses, street, open field,...). I need these files to be ...
0
votes
1answer
453 views

How to remove black box around georeferenced grayscale image in QGIS?

i'am trying to georeference a grayscale image (*.tif) in QGIS 2.2.0 Valmeria. It is working but QGIS draws a black box around the georeferenced raster image. If i use the option set 0 transparent, not ...
0
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0answers
39 views

Credential Dialog, disabling default Realm information messages disclosing password

I'm using the QgsCredentialDialog for determining user access to the database. When a user is failing to log in correctly the log in credentials are shown in the dialog (Fig. 1). (success, uname, ...
3
votes
1answer
438 views

Expand raster extent and set expanded values using nearest neighbor sampling

I have run a hydrodynamic model which has given me a grid of surface elevations throughout a bay. I am trying to process the results in ArcMap (or QGIS if needed). My goal is to take the current grid ...
0
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1answer
70 views

Clipping several raster layers to the same exact size QGIS

I'm new to QGIS, sorry if this is a newbie question... I need to clip about 40 different raster layers from one vector layer (that has the boundaries of 4 neighboring countries) but I need them all to ...
0
votes
1answer
707 views

How do i create a flow line map for my data? [duplicate]

I am trying to illustrate a passenger travel flow map from a road terminal to several destinations on a road layer. I have QGis and ArcGIS, but I don't know much on how to start the work. I already ...
2
votes
2answers
506 views

Automating the production of GPS-compatible map tiles from georeferenced raster maps

I have a set of TIFF maps that I want to load onto Garmin GPS 62s units. The maximum size for each tile on the GPS is 3Mb and less than 1 million pixels. I manually produced one tile, following this ...
0
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1answer
98 views

How to convert this geometry location format to a qgis usable format?

I am a beginner with regard to dealing with gis information, so please bear with me. I would be obliged if someone could help. I have data on asssembly constituencies of Delhi, with these ...
3
votes
2answers
567 views

How to increase label size of OpenLayers plugin basemap layers?

For QGIS 2.2.0-Valmiera, how does one increase the label size of OpenStreetMap layer or any other basemap layer? Presently the labels are way too small to read. For example, I find that for the same ...