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

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3
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68 views

Problem with performance when loading PostGIS layer using pyQGIS

I'm having a question on loading a PostGIS layer into the project from my QGIS plugin. The code is like this: uri1 = qgis.core.QgsDataSourceURI() uri1.setConnection(str(host), str(port), ...
3
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71 views

Create vector grid from canvas using script

I've modified "Hex grid from layer bounds" script to my need. Just added cellsizex and cellsizey. Changed the hexagonal - 3 to "1" to make it as a square grid. Is it possible to include an option to ...
3
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0answers
101 views

ISOdata classifier in QGIS?

Is there a function that produces an ISODATA unsupervised classification in QGIS? The only unsupervised classification function I can find is a KMeans.
3
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0answers
59 views

Connecting QGIS 2.x to Firebird Database via ODBC?

I tried to connect a Firebird Database in QGIS 2.2 and 2.4 via ODBC to a database and get following error message: Unable to initialize ODBC connection to DSN for SYSDBA/masterkey@Akdees ...
3
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0answers
91 views

Performing buffering and intersection with script in PyQGIS

I wrote a script that performs the intersection of two layers: The first Layer -> layer1, represents the rivers The second Layer -> layer2, represents a set of circular dots distributed in a ...
3
votes
0answers
664 views

QGIS 2.4.0 Mac Yosemite compatibility

I just upgraded to the Beta 2 version of MacOS 10.10 ("Yosemite"). I'm getting an error when I try to "drag and drop" shape files into QGIS. I'm running QGIS 2.4.0, GDAL 1.11, and MATPLOTLIB 1.3.1. ...
3
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117 views

How to calculate percentages using QGIS field calculator expression?

I am new to QGIS. I am wanting to calculate a field using other fields and some operators. Here is my expression: case When "RVM_CAT" = 'B' OR "RVM_CAT" = 'C' Then ("PC1" /100) * "RE_ha" When ...
3
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0answers
166 views

Startup python script to re-join layers

In QGIS 2.2, there is a bug which involves using the JOINS properties on a vector layer (that is already being joined with several other vector layers) whereby the attributes are not fully loaded. ...
3
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104 views

Creating one DEM from multiple ASC files

I am struggling with this several days and now its time to ask how to do it in QGIS. I have very detailed 27 ASC grid files with overall size of 9 GB created from 1m contours of large area (600 m2). ...
3
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64 views

Can you use wildcards for column headers in Field Calculator?

I know you can use wildcards for fields like so (in the Field Calculator): case when "column" ILIKE '%example%' then 1 else 0 end Can you do something similar for the column headers themselves? I ...
3
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44 views

Option for 360 degree movie embedded in Open Source GIS software?

Is there any Open Source GIS software available to embed 360 degree movies with the map? For a COTS example, there is the Active Link Vision (ALV) extension for ArcGIS from IWANE.
3
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72 views

IS it possible to run GRASS commands in the QGIS graphical modeler?

I have a geoalgorithm set up in the graphical modeler and everything runs except for the GRASS commands. It is really frustrating because when I execute these commands on their own they work just fine ...
3
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166 views

QGIS API - Print Composer Template produces empty map?

I have a print composer template which I'm trying to populate with different subset queries from a CSV-derived vector layer using the Python API. However, all the output PDFs contain everything except ...
3
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0answers
101 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
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0answers
41 views

Looking for a QGIS solution to make aerial imagery ArcSDE compatiable

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 ...
3
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0answers
192 views

Why does multi-threaded rendering not use all the CPU potential in QGIS 2.4?

I have just downloaded QGIS 2.4 which is great and ran some tests. I have enabled the multi-threaded rendering but it seems that the program do not use all the potential of my CPU. Attached pic shows ...
3
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0answers
68 views

How to find the minimum number of inspection points?

I am working on a pipeline inspection project and there is a high liklihood that some inspection tool deployment/retrival station will need to be installed on the pipe network. the problem is ...
3
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0answers
76 views

Is there a “Disperse Markers” tool for QGIS?

I am using ArcGIS, but either I would like to use QGIS and maybe want to switch completely later. A have a point overlapping problem, as a result of geocoding of addresses. I have not found any ...
3
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183 views

How to fix “Raster layer: Provider is not valid” error when loading PostGIS rasters?

I compiled and installed the current QGIS master as usual and I imported some raster data into my postgres 9.3 database with postgis 2.0.2 extension. Whenever I try to import the raster data into qgis ...
3
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69 views

Using Field Calculator to Convert Data Type In Field

I am trying to convert a field that is listed as "String" because it was imported into QGIS as a CSV (rural poverty population percentages by county in NC). I need to convert the percentages field ...
3
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0answers
182 views

Does QGIS support .sld style files for raster layers?

I'm currently looking at the documentation for geoserver, and I'm trying to load a raster and .sld file in QGIS to see if I can edit .sld files for raster layers. The .sld and raster are located here: ...
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45 views

How to setup default toolbars and menu item?

I need to customize the UI for a group of users at another office. I want to turn off a bunch of toolbars and menus that are not needed. I know how to save my configurations (Settings -> ...
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89 views

Creating a new raster based on pixel value of original raster using raster calculator but new layer is not evident

I am trying to create a new raster based on a current raster (w001001 - NVIS) which has one paletted band, with palette values ranging from 1 to 29, with each palette/value representing a vegetation ...
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147 views

How do I set the composer layout units to inches?

I open an new composer and select ANSI A for my paper. The notation after the name is "Letter; 8.5inx11in", but the width and height are displayed in mm, and the units selection is grayed out, so I ...
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153 views

QGIS Select Single Feature not correct in attribute table

For some reason, QGIS is not displaying the correct row of my data when I click on a feature with "Select Single Feature" or even the other select tools. I have a point database linked from mysql. ...
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197 views

How can I make use of the $scale function in QGIS data defined properties?

In QGIS 2.0 I can use with success the $scale function in the labeling expressions. When I tried to use it for symbolizing in the data defined properties it has a value of 0. Is there a way to make ...
3
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0answers
59 views

How to create a custom enterprise QGIS installer with plugins and symbols?

I am looking at installing QGIS at a company level. I would like my installer to install specific plugins, and add our company map symology. Are there any ways to do this? I have seen post about ...
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174 views

How to create a chart of the altitude of points?

I am using shapefiles with basic informations including the x-, y- and z-coordinates. I want to see how the objects (in this case points, which are finds from an excavation) are scattered along the ...
3
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144 views

Handling non-spatial data for QGIS projects with Camelot

Most of my projects include data which is non-spatial or which is point data and can be managed by a regular relational database. Previously I found Manifold and ms-access were a good combination ...
3
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0answers
91 views

Is Dynamic Traffic Format supported by QGIS?

I have to merge (Dynamic Traffic FORMAT) DTF file into QGIS. This data is only available from NAVTEQ or TOM TOM. When I have searched ArcGIS network analysis tool, there is a clear option for adding a ...
3
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0answers
156 views

QGIS does not read ESRI Geodatabase correctly

I have a geodatabase from the EPA that does not seem to me reading correctly with Quantum GIS. When I open the attribute table the first two columns have the same data. The first column is CERCLA_ID ...
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217 views

Create a path following a road, interpolating from a set of points

I have several hundred vehicular routes within a city from which I wish to create shapefiles. These take the form of directions such as "From Green Street, turn left into Brown Street, Right into ...
3
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307 views

QGis Save Raster as Rendered Image

In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image". When selecting the Rendered ...
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0answers
118 views

Can extracting raster values work in polygons' CRS without raster resampling?

I am trying to extract raster values using polygon layer with different CRS. Raster is in WGS84 (EPSG:4326) and the polygons in UTM (EPSG:23031). 1. If I want to work in the projection of the ...
3
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213 views

Multiple text formats in a qgis label

Is there any way to have multiple text formats in a single qgis label? I am making a map that shows mountain summits. Many of these summits have more than one name and I would like to show each name ...
3
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0answers
120 views

Why are my raster mean and standard deviation -1?

I have a set of about 25 rasters whose descriptive statistics I have been examining. The data in the rasters were calculated in Python and the rasters were created using Python-GDAL. In all but one ...
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0answers
35 views

Why are there changes in location when printing inserted points?

Añadí una capa de texto delimitado por comas y luego agregue una imagen satelital de google earth. Realizo un diseño de impresión y al imprimir cambia la ubicación de los puntos en varios metros. Cual ...
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0answers
313 views

Problems printing OpenLayers Pluggin Maps To Scale

It the print composer I can print all maps to scale and satisfactory. However, when I add the OpenLayer, usually Bing Aerial, to the project I cannot print it out to scale. I click the scale box, ...
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382 views

Error in uploading data in QGIS cloud

I want to publish my .shp file using QGIS Cloud plugin. I signed in to qgiscloud.com (free). On create new database it will auto create dbname='fbeudp_mfaphk' user='fbeudp_mfaphk' ...
3
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76 views

How to analyze the signatures for a Landsat clasification with Sextante in Quantum Gis

I’m defining my training data for a Landsat classification. I´m digitalizing the polygons with the field data in QGis and I want to analyze the signatures of the Landsat images to avoid errors. In ...
3
votes
0answers
187 views

Can you set a QGIS print composer to render the map as default?

I have set up a number of templates for the print composer in QGIS. In the Print Composer, there is the option to have the map image displayed in 3 ways: as a blank rectangle with no updates until ...
3
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0answers
100 views

Can layers from Spatialite db be used as input for a Sextante model?

I'm trying to build my first models in SEXTANTE and already fail at the start. It seems not to be possible to add a vector layer which derives from a database. Orginally, the layers are from a .mdb. I ...
3
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0answers
116 views

Is there a tool for automated quality assurance for vector data captured on raster data?

I wonder whether is any tool(or script) in ArcGIS or QGIS which allows to make an automated quality assurance for vector data captured on raster data? vector data on binary raster:
3
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0answers
145 views

How does Zonal statistics handle pixels that are on the border of the polygon?

I am using the plugin zonal statistics to calculate the sum of the raster cells within polygons. How does this plugin handle pixels that are on the border of the polygon, are those cell values ...
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0answers
315 views

How to import PostGIS layer with geography type to QGIS?

I tried to import in QGIS a layer from a PostgreSQL table with a geography type column created through the extension PostGIS. I noticed that QGIS doesn't seem to like the geography column... Here ...
3
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0answers
764 views

How to join data from a CSV to a shapefile using QGIS

I'm new to GIS and new to StackedExchange. I need help joining a CSV of Accessibility data to a LSOA shapefile in QGIS. The process explained here does not work for me and I don't know why. The ...
3
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0answers
181 views

How to achieve better Dissolve results?

I applied the Vector>Geoverarbeitungswerkzeuge>Auflösen (Dissolve) on a zoning plan (see picture zoning plan). I used the attribute village name as the dissolving criteria. The resulting geometry for ...
3
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0answers
219 views

How to Create a Vector Field from Separate u and v Data Files?

I am using Quantum GIS and trying to create a vector field using data from two separate netcdfs. One contains the u data, one contains the v data. Can this be done, and if so, how? Thanks. Jason
3
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0answers
295 views

Building Qgis-1.8 on Scientific Linux - a sip error occured

I'm on Scientific Linux 6.3 and after trying to build Qgis 1.8 fter "ccmake" I got the error: [ 89%] Built target translations [ 89%] Generating analysis/sipanalysispart0.cpp, ...
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118 views

Why doesn't Polygonizer copy the line ids to my polygonized shapefile?

I am trying to convert a line shapefile into a polygon shapefile using Polygonizer plugin, and when my new polygons are created all the cells in my id field are "Null", although I have clicked "copy ...