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

learn more… | top users | synonyms

2
votes
1answer
40 views

QGis QDir remove directory problem

I am currently developing a QGis plugin and I need to create and remove directories and I use PyQt. I don't know if my problem comes from PyQt or QGis. So my program creates folders, that works all ...
2
votes
0answers
42 views

QGIS : How to calculate centroid on polygons with holes

I try to compute the centroid of polygons with holes on qgis. I did not manage to do it directly, I had to make a conversion to convex hulls before extraction. I crashed my pgsql server trying to ...
0
votes
1answer
69 views

Finding Wgs84 coordinate from ascii grid and calculating scale over a slippy tile map?

I am currently trying to calculate the wgs84 coordinate from an ESRI ascii grid file, which the xllCorner and yllCorner coordinates are I believe in Cartesian coordinates, here is a sample of the ...
3
votes
1answer
38 views

How to order QGIS raster layer style?

I have single band raster files that I am trying to style using Singleband pseudocolour under the Layer Properties, Style settings, and a colour map textfile that I upload for styling. When I upload ...
0
votes
1answer
55 views

Convert shape into a shape file in QGIS

I seek for a way to convert, in the print composer, shape into shape file. I added rectangle in the print composer with "Add shape" function I try Rectangles ovals digitizing plugin, but in create ...
0
votes
0answers
17 views

Group points in polygons [duplicate]

How to group points into polygons? In Qgis if I want to render a point vector layer into a polygon layer, grouping all same colors.
0
votes
2answers
35 views

Group points and compute area

In a point vector layer, how to compute area for 4 defined ranges of values of one attribute? On the example below, I want the total area for each of the 4 colours.
1
vote
2answers
46 views

What method does QGIS Merge Rasters tool use?

I am trying to merge rasters in QGIS and want to set a priority order for merging so that the values from the highest priority raster are used in overlap areas (the “FIRST” merge/mosaic method, I ...
1
vote
0answers
32 views

Align Geotiff images in Qgis

I generated 3 drone maps of one area. The individual images were stitched using dronedeploy. Each map has some overlap with others. I imported all 3 geotiffs as rasters in Qgis and overlay them. ...
3
votes
1answer
46 views

QGIS 2.14 2.5d render appears different in composer and map views

I'm experimenting with 2.5d rendering for the first time. It seems to me that the objects are being rendered in a different order between the main working environment and the map composer. I'm ...
1
vote
0answers
36 views

Missing graduated method: size

I just can't find the size changing method for the graduated style. I have an integer containing column, and I would like to display it with icons which are bigger if the value is higher. So, is ...
1
vote
2answers
30 views

Using QGIS, how to save an attribute table as sqlite?

With 2.14.1 under Windows 10, I am trying to save a .dbf attribute-only table as a .sqlite table. However, the response is an error. My procedure: right-click the .dbf in the QGIS table of contents ...
3
votes
1answer
33 views

How do I export data points from topology checker into an attribute table?

I used topology checker in QGIS to find all dangles in my roads polyline shapefile. The topology checker returned about 528 dangling ends, also called errors. How do I save these points into an ...
2
votes
0answers
58 views

How to add plugin icon to status bar using PyQGIS?

I would like add my plugin icon to the status bar at the bottom of the screen. How would I do that? (QGIS API documentation on statusBar() seems to be leading to the QT docs and that site is down ...
2
votes
2answers
137 views

QGIS 2.14.1 Processing Toolbox GRASS 7 .NVIZ Not working

I have a problem with the command GRASS 7 .nviz in QGIS 2.14.1 installed through QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe.md5sum all GRASS commands work exept .nviz / nviz7 images: I test with ...
9
votes
4answers
309 views

How to snap a road network to a hexagonal grid in QGIS?

I'm trying to use QGIS 2.14 to snap a road network to a hexagonal grid, but I'm getting strange artifacts. I've created a hex grid with MMQGIS, cells are approx 20 x 23 m. I've buffered the road ...
3
votes
1answer
88 views

Batch project creation

I have a list of csv files "name.csv" that I want to use to make various analyses in QGIS. I would like to automatize the following steps for each file : create new project name_main.qgis; import ...
1
vote
1answer
24 views

QGIS GdalUtils runGdal function throws error for second argument

I am trying to use a script provided in the QGIS Python Cookbook by Joel Lawhead - its a simple script that georeferences images based on control points via the gdalwarp function. (p.124 in the book) ...
2
votes
2answers
41 views

Using QGIS shapefile layer in ArcMap project?

I created a QGIS shapefile layer in QGIS that I want to give to a friend of mine for his ArcMap project. Will he be able to open and use my work?
1
vote
0answers
24 views

QGIS x ArcGIS - Geoprocessing Vectors in Geographic Coordinate Systems [closed]

Is there a possibility of in future versions of QGIS, the software be able to geoprocess vectors (clip, buffer, intersection, etc.) in Geographic Coordinate System, and not only in UTM? In ArcGIS, ...
2
votes
1answer
51 views

QGIS modeler: count points in polygons

it is the first time that I’m using the QGIS graphical modeler and I found some troubles (QGIS 2.14.1). I’m trying to count points that intersect with polygons in a vector grid, but filtering the ...
3
votes
1answer
60 views

Convert xyz points to topography and calculate mean slope

I am working on point data (x, y, z) in meters from origin. I have between 24 and 35 points for each plot (10mx10m), with random locations. I would like to modelise topography over the whole plot in ...
0
votes
1answer
24 views

Error in the connection to Oracle Spatial from QGIS

I am not being able to stablish the connection to an Oracle Spatial server in QGIS. Apparently I have the connection configured accordingly with QGIS documentation, but it stills gives me an error: ...
2
votes
1answer
33 views

Hook for deinstallation of a QGIS plugin

I have a plugin that creates a lot of settings in the Options | Advanced dialog. I'd like to clean up a little on plugin install. Is there a hook I could use ? unload() is run on any QGIS shutdown ...
2
votes
0answers
30 views

QGIS: Merging raster files produces error

I'm trying to merge (Raster -> Miscellanous -> Merge) four raster files into one. Each file has same CRS and are saved as .tif files. Merge produces error: "The process crashed some time after ...
0
votes
0answers
28 views

Feature symbols in the legend don't match those on my map?

I have edited the features on my map using the draw effects tool (colourize, glow etc). However, in Print Composer, the legend shows these feature symbols in their original form. How can I get them to ...
1
vote
1answer
45 views

Global name not defined, is this a syntax error?

I have been working with classes, and I have fixed several mistakes related to indentation, but in this case I have been checking all the possible errors. It might be a concept error. If someone can ...
1
vote
0answers
32 views

QGIS python support disabled

I'm having a problem with the python support of my QGIS version. When I start QGIS, I get the error message: Traceback (most recent call last): File "", line 1, in ImportError: Module use of ...
1
vote
1answer
70 views

Symbolizing OSM rail lines in QGIS

I am struggling to come up with a proper layer style for a rail network extracted from OSM in QGIS. I just want active rail so I choose the "rail" tagged features (rule-based rendering). But since ...
2
votes
0answers
83 views

display issue in qgis 2.14 : features appear and disappear

I have several virtual layers in my project. One of them contains 6 lines. Depending of the scale, at least one line disappears from the canvas for an unknown reason. I heard that sometimes, creating ...
2
votes
2answers
34 views

QGIS Merge rasters without projection edges

I have been trying with no luck to merge forest canopy rasters available through the NLCD (e.g. Grids 102 and 105) using QGIS in Mac (as well as R, and SAGA in Windows). The GeoTIFF grids import and ...
1
vote
0answers
25 views

Can typical Meets and Bounds (angles and distances) drawings be accurate in QGIS?

I’ve been working with parcel boundary shape files (.shp), standard satellite imagery, and Meets and Bounds (angles and distances) site maps / legal descriptions for a few weeks. Wondering if those ...
2
votes
0answers
36 views

Adding layers in QGIS with predefined order in TOC and also make some of them to have visibility turned off when added

I am working on a project and I have a lot of shapefiles with the same name but with different data and when I add them to QGIS they are sorted randomly in TOC (Layers Panel). Can I configure their ...
1
vote
1answer
34 views

PyQGIS: How to find features <within> another feature

Using a spatial query in QGIS Desktop to select features of layer MTA_ACQ_TE_polygon that are within features of layer nts_snrc_50k works, but I am attempting to do this programatically in PyQGIS, ...
1
vote
0answers
19 views

How to upload data from QGIS to a SQL Server?

I'm new at QGIS. I'm wondering if there's a native way or plugin to allow me to upload a shapefile into my SQL Server directly from QGIS. So far the only solution that I could find is the Shape2SQL ...
2
votes
0answers
39 views

Why cant we launch QGIS.exe? Why we have to use QGIS.bat?

QGIS.bat - it is calling some other batch files (all of them also setting up path variable and some more variables), sets some more variables and setting up PATH. I have done that in system ...
2
votes
1answer
54 views

PyQgis: During editing, add new feature attributes

Workflow: Start edit mode -> New feature is created -> On the console (pyqgis), new attributes are set -> Exit edit mode. Problem: The attributes are not saved. Only after completion of the editing, ...
1
vote
1answer
19 views

Getting QGIS working with Arcgis feature server - crs issue?

I am having difficulty getting the feature service below to line up properly with other layers. It renders fine by itself. How do I determine what crs this service is using? I am adding this layer ...
3
votes
1answer
51 views

Calculating median elevation for local authority areas using OS Terrain 50

I haven't been able to find anything that could comprehensively help me with my problem. I want to calculate median elevation for UK local authority areas. So far I've taken the OS Terrain 50 data ...
1
vote
1answer
13 views

Resources for digitizing in webmap and export? [closed]

Its possible with Google Map API to draw geometries and points. And exporting as well I assume. Is there other alternatives, probably based on Java that can do the same job? I've been researching on ...
0
votes
0answers
30 views

Measuring correct line length from a 2D polyline using 3D raster QGIS

I am trying to measure the correct line length of a 2D polyline when draped over a 3D surface. In theory I would expect the line length to change when moved from the 2D to 3D. The polyline is spaced ...
1
vote
1answer
18 views

Joining attribute data from one layer to another layer in QGIS 2.12.2-Lyon

I have a polygon vector layer that I am trying to join its attributes to a point vector layer. The problem is that the polygon layer consists of grids that are numbered 1-150 (ID) and I am trying to ...
2
votes
2answers
82 views

Variation on a density map QGIS

I am trying to figure out how to make a map that can represent the density estimates that I have. The estimates are tied to points, but are for 1 hectare (100m*100m) areas of which the point is the ...
1
vote
1answer
53 views

How can I align perfectly 4 topo sheets?

I have 4 topo sheets and i want then to align perfectly Would I have to georeference each image again? Or is there a more simple method?
4
votes
1answer
53 views

How do I update joined data from MySQL programmatically?

I have a point vector layer (Sensores) in my QGIS project, I also have a MySQL database layer (SensoresDB) containing only data. I have joined these two layers in order to geographically reference my ...
0
votes
1answer
21 views

Converted a USA Contiguous Lambert Conformal Conic vector shape to WGS 84 EPSG 4326 and dimensions changed ~20%

Needed geometric tools to draw lots of parallel lines representing flight paths for taking overlapping aerial pictures - Lambert Conformal Conic was ideal (I thought). But saving to my project's ...
1
vote
1answer
23 views

Edits in Oracle Spatial Layers

I have an Oracle spatial layer that is built on top of a multi table view. When I make a new feature in QGIS, I get an error when I attempt to the save the edit. When I look in the database and ...
1
vote
0answers
22 views

Change CRS, but the image position also changing

I have 2 overlapped image, one is an aerial photo in CRS EPSG (4326) WGS 84, and one is a satellite image, in CRS EPSG:32648 WGS 84/UTM zone 48N. I need to georeference the aerial photo compare to ...
1
vote
0answers
19 views

Calculating the distance between points and parts of a underlying raster set

I need your help with a calculation of the distance between points (cities in this case) and forest (raster data). Is there a possibility to collate to every city the distance to the nearest forest ...
1
vote
1answer
15 views

QgsComposerTextTableV2 minimal implementation?

I would like to use the richer data and styling API QgsComposerTextTableV2 offers. However I get this error when adding it to the composer: TypeError: QGraphicsScene.addItem(QGraphicsItem): argument ...