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

learn more… | top users | synonyms

4
votes
1answer
121 views

Correlation between corn yield and planting speed using ArcGIS for Desktop or QGIS?

I have two maps that originally come from a harvester and a tractor as shapefiles: Corn Yield and Planting Speed. I would like to know what would be the best procedures to statistically answer the ...
1
vote
1answer
59 views

how to get area in qgis 2.6.1 brighton?

I'm using QGIS 2.6.1 brighton, and I have a problem in computing the area of each layer. I was actually working on the map of our municipality and I would like to compute the total area of the ...
2
votes
2answers
100 views

Change detection between binary rasters in QGis

I have two binary rasters, raster1 and raster2, which represent the distribution of grassland habitats inside an area in two different moments in time (raster1 = older, raster2 = recent). In both ...
0
votes
1answer
75 views

Export qGIS Print Composer PDF with searchable text labels

I have point features with text labels on my map. When I export as PDF, I can search elements that were constructed in the print composer, like the legend, scale bar, etc. However, labels of features ...
1
vote
0answers
38 views

How to generate map tiles including world files in QGIS?

Is there any way to export bitmap tiles including world files from a QGIS project? I've tried QTiles but it seems not to support world files.
1
vote
0answers
68 views

How to create a sequential unique id by groups?

I'd like to use the field calculator in QGIS to create a unique feature (polygon) id that reflects different levels in a geographic hierarchy. So say I have a REGION attribute within which there are ...
0
votes
0answers
41 views

how to add vectorlayer in a mapcanvas with a raster

I am working in c++/qt4.8.5 with qgis api 2.8.2 For my application I had to load a raster in a mapcanvas, then with different action I had to add pint , line or polygon Is there a simply way to do ...
1
vote
0answers
165 views

QGIS Intersect returns empty layer

I'm following these instructions from the FCC: https://transition.fcc.gov/form477/Geo/finding_census_blocks_in_qgis.pdf Everything works just fine up until step #6, where the Intersect tool is used. ...
2
votes
1answer
113 views

How to get the center line between two linestrings

Where is the track of a ship when it is shipping always in the center of the English Channel between the coasts of Great Britain and France? I started with 2 linestrings and I created a lot of ...
1
vote
0answers
90 views

Spatial correlation using QGIS?

I'm looking into performing a spatial correlation test of 2 matrices to see where they overlay. To do so I need to create a grid layer of 2.2km2 around the coordinate points. I've tried the vector - ...
1
vote
1answer
57 views

I am using QGIS 2.6.1 but i dont know how to split a state into two states? [closed]

I have a .shp file of the states but my file is older one and after that one state in India converted into two different states so how can I separately show both the states on the map using QGIS. I ...
2
votes
1answer
485 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 ...
3
votes
1answer
628 views

Using GPS tracking with QGIS and Panasonic Toughpad

I'm using QGIS with a Panasonic Toughpad FZ-M1 with inbuilt dedicated GPS. I can connect okay to the GPS using View --> Panels --> GPS information. Satellites and signal strength show up, but no GPS ...
2
votes
1answer
167 views

Problem with Distance Matrix in Qgis 2.83

I want to calculate the distance of archaeological sites to the nearest river. Following this question Calculating the minimum distance between points and polygons in QGIS I extracted the nodes of ...
1
vote
1answer
41 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?
1
vote
2answers
35 views

Putting result of selection of plots in frame of QGIS?

I have made a plugin for QGIS in pyQt. Then I can make a query from a PostGIS database and I get the plot or bunch or plots results of that query in a layer. This layer is overlapped on the top of a ...
2
votes
0answers
58 views

How to copy elements and attributes?

I need to copy many elements (and their attributes) from a shape file and paste to another one. If I use copy/paste functions it paste only the polygons but not the attributes, How can I solve it?
1
vote
1answer
82 views

How to re-render only a single layer on a mapcanvas?

In my application I have a mapcanvas that contains several layers. some of layers need to be updated or rendered again because data has been changed ( like the geometry or some attributes ) Is there ...
2
votes
1answer
86 views

pyqgis traversing subgroups and group layers

I am trying to find the name of subgroups using pyqgis. I have been trying to use Playing with subgroups I am however unable to traverse and get the names of the subgroup. I have tried the code on ...
2
votes
1answer
608 views

How connect points with lines in QGIS?

I need to connect points with lines in QGIS. I am in this fresh out so I'm not sure how to do it and I need a little bit help with this. I read several posts i and tried to do something about it but ...
1
vote
0answers
116 views

WKID issue when adding raster layer from ArcGIS “mapserver” to QGIS via REST

QGIS docs here describe how to do this. I am trying to add a layer from this MapServer: gps.digimap.gg/arcgis/rest/services/JerseyBaseMap/MapServer When I try the following command from the Python ...
2
votes
1answer
182 views

Grid or True North In QGIS

With Qgis general settings and changing nothing on the preferences window, which north system (true north or grid north) will be activated ? Would it be determined by selection datum, for instance ...
3
votes
1answer
331 views

D3 javascript and GeoJSON: lines in Stockholm map very strange

All the code and shapefiles that I'm using are available in this GitHub repo. I'm trying to draw a map of Stockholm with D3. The shapefile looks ok in QGIS: However, drawing the GeoJSON produces ...
3
votes
2answers
165 views

pyqgis add a picture

I am looking for a way to add a picture to my map using pyqgis. Are there any examples of how to do this. I know it can be done using the classQgsComposerPicture. I am not much of a programmer so I ...
3
votes
0answers
78 views

How to calculate the area within a 4m clipped buffer derived from a raster

I am using QGIS 2.8.3. I started by classifying my area into habitat types using the semi-automatic classification plugin (SCP). Then I added points, and a 4m buffer around the points. So I could then ...
3
votes
1answer
89 views

When creating an expression in QGIS, is there a way to reference the next record and previous record?

I have a set of points from a GPX file, and would like to create a heatmap from them, with the points weighted on the amount of time spent at that point. I want to create a calculated field in QGIS, ...
2
votes
2answers
117 views

Problems installing QGIS on Windows Vista

I have tried several times on several windows vista machines to install QGIS (both versions 2.10.1 and 2.8) but with no luck. It seems to install fine without any errors but when the installation is ...
3
votes
1answer
479 views

cannot convert shapefile into GeoJSON

I have downloaded a shapefile of Stockholm (files on GitHub). I'm trying to convert the shapefiles to GeoJSON with the ogr2ogr command line tool. It does not work with the following error: Export ...
1
vote
1answer
102 views

Can I get rid of the borders around the colour boxes in QGIS Print Composer Legends?

If you look closely at a legend in the QGIS Print Composer, you'll see that each colour box has a hairline (1 px) border. How can I remove these borders? By playing around with the settings, I've ...
1
vote
0answers
20 views

Expression geomnearest not found

I have been making some new printer composers in a project I am working on in QGIS. I had implemented the use of expressions to create content for the title block, one of these is the geomnearest ...
1
vote
1answer
371 views

Delete (don't hide) text annotations in QGIS

I feel like this question should have a really simple answer, but I can't find it anywhere. I added an annotation to my map while experimenting with different buttons, and it wasn't at all what I ...
2
votes
1answer
257 views

Move feature in front

Is it possible to move feature in front of another? If I have smaller polygon and I draw larger polygon over it, is there a way how to move the smaller one in front? Is it possible in QGIS or better ...
2
votes
1answer
152 views

How to update a postgres/postgis table periodically with multiple data?

I have created a postgis table from point.shp with 5 fields containing 20 records. Now I want to populate the table with another 150 records keeping the previous 20 records so that the total records ...
1
vote
1answer
95 views

QGIS delimited text import CRS not being defined

I've recently updated to both the long term release and 2.10 versions of QGIS and the delimited text plugin has stopped working. Everytime I try to add a CSV file and say ok on the plugin it no ...
2
votes
1answer
82 views

Exporting only certain fields from a PostGIS table using QGIS Python

I'm trying to export tables from a PostGIS database into MapInfo TAB files, but only certain rows and columns. I have my rows exporting right, using a query, but I'm stuck on just getting the columns ...
1
vote
1answer
42 views

No export dialog on QGIS 2.8 and 2.10 with Mac OS X Yosemite?

I'm trying to work out the map making tutorial here: http://www.qgistutorials.com/en/docs/making_a_map.html When I try to export an image or pdf or even print the map I built in the composer, I ...
1
vote
1answer
54 views

2.10 program group option to open QGIS with GRASS

I have installed QGIS 2.10 on Windows 8. I cannot find the 'option' to start QGIS with GRASS - as has been previously answered. Have I possibly missed something in the install? Is this 'missing' ...
3
votes
1answer
65 views

Display or export gdal_translate exponential scaling equation

I have an GeoTiff raster that contains elevation information at each pixel. As OpenLayers 2 can't display GeoTiff, I convert it to a PNG image and have to apply an exponential scale so the resulting ...
2
votes
1answer
58 views

Plotting points on a map based on address text string of location

This may be a naive question, but I'll try anyway. I am working in QGIS, and I have a shape file with more than 2000 rows containing information about specific trees in a botanical garden; their ...
1
vote
0answers
15 views

Project do not open anymore because of a minidump [duplicate]

I have closed my project two days ago and this message appeared : minidump déposé dans C:\Users\wwf-adm\AppData\Local\Temp\qgis-20150903-171144-3780-1392-8fdd08a.dmp When I try to open my project, I ...
1
vote
1answer
90 views

Problem creating polygon in a layer

I am working in c++ qt4.8.5 and api qgis 2.8.2 c++. In my application I had to put polygon to define attractive zone. I found a great post in stackexchange (86812). I have based my on this post and on ...
3
votes
1answer
272 views

How to fix QGIS Plugins crashing with “NameError: name 'pyplugin_installer' is not defined”?

I recently switched to Windows 10 and therefor did a clean Windows and QGIS 2.10.1 Install. QGIS worked fine, I reinstalled all Plugins, that I used to have. No Problems. Today I switched on the PC ...
3
votes
1answer
146 views

Tilted projection in QGIS

I'm trying to add tpers projection as a custom projection in QGIS 2.10.1 In the Custom crs dialog I'm adding the proj.4 text: +proj=tpers +h=500000000 +lat_0=19 +lon_0=99 +x_0=0 +y_0=0 +a=6371000 +b=...
1
vote
0answers
38 views

How to best populate points within a polygon with a set of rules

I've got a polygon (a Circle) with a certain size. I want to put points inside it, as much as I can, but with a set of rules : Points can't be near each other, up to 500 meters. Points can't be near ...
1
vote
2answers
76 views

QGIS Processing Plugin Not Loading “RuntimeError: maximum recursion depth exceeded in cmp”

I am having serious issues with my QGIS program regarding the Processing Plugin. Upon start-up and if I turn on the plugin within the program. I have uninstalled and reinstalled the program. Have ...
1
vote
1answer
302 views

QGIS Generating a Lat/Long Degree Grid in Composer

I made a map in WGS84, which is positioned and referenced correctly. Now I loaded the map into the Composer and added a grid, with horizontal and vertical lines each 500 world units (m). When I ...
6
votes
2answers
362 views

How can I average point features spatially in QGIS?

I have a GPX file with track points and I want to average the points spatially to improve accuracy of the point feature. I can't just make a polygon and find its centroid as the number of overlapping ...
1
vote
1answer
58 views

How to create a specific svg file with data from a feature

I am working in c++/ QT4.8.5, with qgis api c++ 2.8.2 I have to display a dynamic icon for a feature. some of the data change periodically and in order to display the change i need a svg that can get ...
3
votes
1answer
110 views

QgsExpression using complex sql and python subsitution

I have a sql statement i am running in postgres fine and would like to transfer it to a QgsExpression mainly because I have loaded the layer in Qgis. My sql is: select column a,column b from table1 ...
0
votes
0answers
12 views

Tracing a raster layer in QGIS [duplicate]

I have a basic map I would like to trace into vector form in QGIS. The map is just a JPEG and has no coordinate reference data. Whenever I import it into QGIS, it ends up as a tiny speck at 0,0. How ...