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

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1answer
197 views

Simplifying Shapefile without risking Spatial Accuracy?

I am building a feature for a web application. Basically would use the ABS (Australian Business Statistics) data to render the regions on the Google Maps. I am able to implement the basic working ...
-1
votes
1answer
719 views

QGIS, Multiple lines and wrap on character? [duplicate]

How to make wrap on characters in Labeling layer settings. I tried various solutions, but it works. Does anyone know how to do?
2
votes
1answer
35 views

QGIS - delete polys based on vector line layer - possible?

I have a layer of polygons and a layer of vector lines. I want to delete any poly that is touched/crossed/intersects a vector line. Is this possible? I have tried the Geoprocessing Tools. Looks ...
1
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1answer
159 views

I'm not able to save edited layer connected via PostGIS in QGIS

I have project and i was doing editing layers in QGIS. These layers are connected in QGIS via PostGIS. 1 layer of the 4 layers was saved correctly but other layers gave me error message. Error ...
1
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0answers
161 views

QGIS2.4.0: Cannot import qgis module in python “from qgis._core import * \n DLL Load Error”

Having some trouble importing qgis into python. I'm very new to python so it could be a simple mistake. The path seems to be correct. It gets this far: File "<stdin>", line 1, in <module&...
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0answers
80 views

Copy parts from several attribute tables in shapefiles?

I have several shapefiles from which I wish to take parts from their attributes tables to make a new attributes table. Is this possible without destroying the original attributes table? I have ...
4
votes
1answer
425 views

QGIS: Plot a layer given with Longitudes [0 360] to [-180 180]

I have a world map in correct Longitudes from -180° to 180°. Additionally, I have a shapefile of data from South America, which shows at 290° instead of -70°. How can I reproject it using QGIS?
3
votes
1answer
68 views

Changing attribute values in a memory layer

I'm trying to change attribute values in a memory layer. My memory layer is defined in this way: pro.addAttributes([QgsField("nom", QVariant.String), QgsField("valeur", QVariant.Int)]) I made ...
3
votes
1answer
197 views

Highest DEM pixel in polygon

I'm working with QGIS and have a big DEM raster layer with height information and a vector layer with many polygons, representing 1 x 1 degree tiles. Now I want to find for every polygon the highest ...
4
votes
7answers
3k views

Clip in QGIS 2.4.0 resulting in empty output files

I'm seeing the same problem to Clip or Intersection tool - QGIS giving empty files trying to use the Clip tool since upgrading to QGIS 2.4.0, but have not been able to fix the problem based on the ...
2
votes
2answers
346 views

QGIS raster clip error: Cutline not of polygon type

I have a raster file and want to clip it, but I'm getting this error: "ERROR: Cutline not of polygon type" what does this error mean and how can I resolve it?
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0answers
154 views

Vector layers without geometry in QGIS?

Using QGIS, I have set up a couple of automated layer additions via the toolbar. After adding geometry in each respective layer (point, lineString, polygon) and saving changes to the layers, the added ...
2
votes
0answers
240 views

Exporting spatialite view to shapefile from QGIS modifies the original data types

We have a spatialite .sqlite database where we have views which are nicely rendered by QGis, with all the symbols and everything!! There are integer fields on the view which are based on fields of ...
2
votes
1answer
853 views

Calculate EVI From Landsat 8 in QGIS [closed]

I have calculated atmospherically corrected reflectance values for Landsat 8. From that, I am getting correct values of NDVI in QGIS, but for EVI I am not getting the correct values. For some images ...
2
votes
0answers
67 views

Align & Sum Grids in Python

I have two grids. One, call it A, is 4320x2160 cells and spans the whole globe. The other, call it B is 8640x3432 and spans the circumference of the globe, but is clipped toward mid-latitudes. Both ...
1
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2answers
460 views

QGIS Convert Polygon M to polygon

I have been using Argis 10.1 and been able to convert polygon m to polygon shapefiles. I would like to do this with QGIS but I am having difficulty in finding the correct tool to do so. Please Help
2
votes
0answers
827 views

I cannot install QGIS 2.4 on my Windows 7, 64 bit machine [closed]

I am running Windows 7, 64 bit and cannot install QGIS 2.4 after several days of trying. I have also tried downloading 2.2 with no avail. I keep getting this error: The text of the error is: ...
1
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0answers
80 views

QGIS crashes when trying to display features form MySQL

I import shapefiles into MySQL using the following command: ogr2ogr -f MySQL MySQL:GIS,host=localhost,user=root,password=root /home/user/Public/myshape.shp -nln Shape_table -update -overwrite -lco ...
3
votes
3answers
272 views

How to display a table with more than one geometry column in QGIS?

In PostGIS, it is possible to use addgeometrycolumn more than once on the same table. Example: I have one table "scenes" with many attributes, and 2 geometry columns: the_geom1 and the_geom2. select ...
1
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0answers
225 views

QGIS Relation Manager

I have a PostgreSQL database with a one-to-many relationship. Here is a reduced example: CREATE TABLE buildings.building ( objectid serial NOT NULL, building_no character varying(40) NOT NULL, ...
1
vote
2answers
925 views

QGis 2.4 - Python 2.7 PyQT4.Qtcore.QStringList Import failed

I receive an import error when trying to import QStringList from the Qgis Python console (or when loading a custom plugin). from PyQt4.QtCore import QStringList Traceback (most recent call last): ...
2
votes
1answer
124 views

How to set QGIS options in standalone pyqgis application

I have a standalone application which uses the QGS api to view and query map layers. One layer is a WMS-C layer which automatically caches tiles which is great. I want to also activate a setting which ...
3
votes
0answers
99 views

access point layer representation in qgis with pyqgis

I am exporting the style of a categorized point layer with qgis: unfortunately my code only extract the size of the symbol in the definition of the properties of the layer but not the ...
7
votes
3answers
6k views

How to export polygon coordinates to CSV (not WKT)?

I am new to QGIS, and I am now trying to export polygon coordinates from a shape file to a csv file, but so far all my attempts have failed. I have found numerous questions and answers about this, but ...
3
votes
0answers
522 views

How to export data from sql server into shapefile in the decimal format in QGIS 2.4?

The last couple of days, I have been working on exporting data from SQL to a shapefile in QGIS 2.4. While converting into a shapefile, the data type changes automatically from Float to Integer in the ...
3
votes
1answer
702 views

How can units be defined in QGIS for the Rasterize tool?

I am using QGIS 2.4 (Chugiak) via the kyngchaos build for OS-X. My question is--when using the Rasterize tool to convert a point vector layer to a raster and using the "Raster resolution in map units ...
3
votes
1answer
245 views

How to add dashed line in QGIS print composer

I want to display two maps in the print composer: a main one, and another showing a zoomed in section of the main map. I've drawn a rectangle over the original region and want to add two dashed lines ...
3
votes
1answer
178 views

How to find and replace a singe word in a string?

How do i find and replace a single word of a string? e.g. Calle Iparraguirre to Iparraguirre I've tried: replace( 'Calle\\s', 'Calle\\s', '') replace( "name",'calle','') and all combinations ...
1
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1answer
194 views

Coordinate System changes after reprojection

I have changed the projections of some Natural Earth Shapefile to "WGS 84/Pseduo Mercator", that works fine (after cutting out the artic), but now the co ordinates of the shapefile are all out of wack....
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0answers
85 views

How to set a defined distance between nodes to digitize in qgis?

Using QGIS (by now I have the 2.4 version) I would like to set some parameter (I don't know if such exists) that would impose a definite or maximal distance between nodes when digitizing a polyline or ...
1
vote
1answer
315 views

PyQgis Message Bar Woes [closed]

Having a bit of trouble with the basics of getting the (awesomely discreet) new user prompt/warning to properly display. Here is the (troubled) code I am using: self.iface ... iface.messageBar()....
2
votes
1answer
842 views

“Data source not valid” problems with QGIS processing

I'm having a lot of problems with QGIS processor. Most of the algorithms show me this QGIS log error: La fuente de datos no es válida. (Data source not valid) This happens with SAGA and GRASS ...
1
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1answer
644 views

PyQGis - Working with Spatialite

I wrote a Vector layer to a spatialite file/db using the dedicated API tool, using valid driver names supported formats by OGR. When connecting to that db, I can't retrieve properly the geometry ...
2
votes
0answers
40 views

Is it possible to drag&drop line precisely 6 meters to right or left?

I use Quantum GIS 2.2.0 Valmiera I have a polyline layer. I can drag&drop polyline nodes by using "Node Tool". Is it possible to drag&drop line precisely 6 meters to right or left?
2
votes
1answer
113 views

A way to transform by special epsg-code

In my country, we have a special epsg-code for transformation (#4649). In the definition (http://www.epsg-registry.org/report.htm?type=selection&entity=urn:ogc:def:coordinateOperation:EPSG::4649&...
1
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1answer
154 views

Shapefile not projecting correctly [duplicate]

I am still new to this, so I apologise if I don't make a lot of sense! I am using QGIS 2.4.0 Chugiak. I am working on a project set to the GDA94/MGA Zone 50 coordinate system with 'on the fly ...
3
votes
1answer
389 views

Where can I find information about the development history of QGIS?

I know very little about early versions of QGIS (far far away from now..) and i'm feeling curious :-) I am looking for various information about the past of QGIS, including: Do you know in what ...
1
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0answers
315 views

Way to split and create buffer space between polygons in QGIS or ArcMap

After performing a feature extraction of rooftops, some of my buildings have been joined together as one polygon. I want to split these large polygons so that each new division is only covering one ...
2
votes
0answers
46 views

Looking for a QGIS solution to make aerial imagery ArcSDE compatiable [closed]

Would like to avoid having to use 3d Analyst and use free raster tools in QGIS or elsewhere to make aerial rasters ArcSDE compatible. This 18 page work flow is what I am trying to use. Any suggestions ...
1
vote
0answers
56 views

Vector Layer Symbol (ism) properties?

I would like to streamline the render of a polygon grid vector layer as a simple line (no fill) via Python coding. I am I bit confused by the implementation referenced by the API. Is it possible to ...
1
vote
1answer
93 views

How to test for multiple map items in Composer using python?

I am building a QGIS plugin and I need to check for multiple maps items in Composer that works on all platforms. Currently I am getting the first map in the composition using the code below, but ...
3
votes
1answer
574 views

Benchmarking QGIS and ArcGIS for Desktop speed for “significant buffer on very large shapefiles”?

I am a newcomer to the world of GIS. I realized that QGIS was relatively similar to ArcGIS for Desktop. I would like to know if the two programs are comparable in terms of computational speed. For ...
5
votes
1answer
226 views

QGIS 2.2 - possible to do a JOINS from the Action list?

I have a set of layers that need to be joined (Layer Properties > Joins) to one specific layer. The reason for this is that I will be updating and adding new layers into my project and would like a ...
4
votes
2answers
243 views

Is it possible to decrease detail level (decrease file size) in Spatialite OSM export?

I currently use Spatialite exports from OSM data (together with Google maps like styles by Underdark) which are very useful for me as the files are easily portable with the project and I do not need ...
3
votes
2answers
2k views

How to set the Identify Feature tool in QGIS 2.4?

The Identify Results window does not appear when using the identify feature tool in QGIS 2.4. I guess there's a check box somewhere I need to check/uncheck, but the settings of the tool changed ...
1
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0answers
283 views

How to export data from sql database in the decimal format in QGIS?

Currently I am working with QGIS and fetching data from SQL server and export it in the format of shapefile in QGIS. While importing the data from sql server attribute table showing data with ...
1
vote
0answers
86 views

Compiling QGIS for Slackware (Slak 14)?

I use a Slak 14 box and tried to install QGIS on it. the compile process goes on for 30 minutes or so (dual Xeon 3.2 ghz) and then I get the errors below. Says the compiler doesn't work. Have had no ...
2
votes
1answer
414 views

How to make crs transformation of a QgsVectorLayer?

I need to transform QgsVectorLayers in python from one crs into another crs. By googling I found the following solution (https://qgis.readthedocs.org/en/latest/docs/pyqgis_developer_cookbook/05_crs....
5
votes
3answers
266 views

How to count polygons in multipart features?

I'm trying to count the number of polygons in a multipart feature. My aim is to have a 'count' attribute to quantify fragmentation of multipart land parcels. I've looked at the field calculator and ...
1
vote
1answer
99 views

How to automatically connect point [closed]

I have to draw all the rows connecting the 2 edges with a line. It's not so hard to it manually, but it takes a lot of time. Is there a way to connect the two edges of the rows automatically? For ...