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

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140 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 ...
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0answers
53 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 ...
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0answers
142 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 ...
4
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3answers
156 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 ...
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1answer
70 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 ...
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1answer
51 views

Why is the SelectionChanged signal triggered every time i click on the layer?

i'm making some experiments with the SelectionChanged signal of a QgsVectorLayer. i try this piece of code : curLayer.selectionChanged.connect(self.test) and "test" print a warning message. The ...
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0answers
57 views

How to programmatically interrupt QGIS initialization and startup

I'm wondering how to interrupt the initialization of QGIS 2.0 on Windows XP before start up. I've put a dialog in one of my plugins that shows up on start up. However, I'd like to make a quit button ...
2
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0answers
113 views

Saving/Loading QGIS style .qml and avoid specified symbology

Is it possible to save QGIS styles without the symbology style? This may seem like a strange question, but I am trying to automatically set the ValueMap widget under layer properties via a plugin for ...
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2answers
65 views

How to calculate regrowth area?

Thanks to Best Landsat-5 TM band combination for detecting fire scars I am able to calculate burnt area in an absolute way (Normalized Burn Ratio). Does a ratio or delta operation exist to calculate ...
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0answers
107 views

How to compute the ls factor equation for USLE model in qgis grass r.mapcalc

To compute the LS factor for the USLE model, the following equation easily works in ArcGIS. How can I perform the same in QGIS under GRASS r.mapcalc? LSfator = Power (("flowaccNW") * ...
2
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1answer
115 views

Add XY Column in QGIS [duplicate]

Following on from a previous question of mine, where I was given coords in degree-mins, I have successfully converted them to decimal degrees, thanks for the help. I have created a CSV file from ...
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1answer
193 views

Does the experimental QGIS2leaf plugin not work on mac OS?

I am trying to get the experimental QGIS2leaf (Leaflet web maps) plugin to work on my macbook air (2012, Mavericks OS), but when I open the outputted index.html file, no interactive image shows up in ...
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2answers
257 views

How to delete column/field in PyQGIS?

How to remove or delete column fields in a shape file using python?
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1answer
165 views

Pulling CSV file directly from website into QGIS?

I want to be able to automatically update my csv files in a QGIS project. My organization has an online database that can easily export csv files. These csv files are constantly updated with new ...
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1answer
178 views

How to perform an attribute-weighted sum of multiple polyline features from a single vector layer?

I have a shapefile of ~8000 polyline vector features representing traffic journeys on road routes. Each has an attribute representing volume of traffic for that journey. The routes are all generated ...
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1answer
93 views

QGIS Filters and Queries

In QGIS is there a way to filter a layer using the Query Builder to show all values which include a particular phrase. For example I have a list of organisations and I want to filter all those which ...
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0answers
68 views

Lat Long to Useable values in QGIS

I am using both QGIS 1.8 and 2.0. So either is helpful. A client has given me locations of trial pits but i cannot load them into QGIS no matter how hard i try. For example, 50°24.711 North ...
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1answer
106 views

Apply new style to selected features in QGis

Let's assume that I have selected some features in QGis. Now all the features in that vector layer already has some style applied to it. Now, I want to apply some new style to the selected features. ...
3
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1answer
42 views

How to select more than one feature using values?

What should I do if I want to select more than one feature using values ? For selecting a single feature, I enter an expression like this which works: "LINK" = 28 Assume LINK as a field in the ...
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1answer
153 views

How to increase the resolution of a 3D image in QGIS GRASS NVIZ

I'm trying to display 3D data in NVIZ within QGIS, but the result appears very low resolution in comparison to the same data in ArcScene. Any ideas as to how to improve the quality would be greatly ...
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0answers
244 views

How to convert data type from float to integer in QGIS?

Currently I am working on importing data from MSSQL to Qgis 2.4. In imported database table attributes are shown in the format of integer ( in attribute table it showing like 48.23 and 16.20 in ...
2
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0answers
125 views

Is it possible to change the default raster style of newly created rasters in QGIS?

If I do calculations on rasters with the raster calculator or other tools, the resulting rasters displayed in my canvas are always in the same default style (singleband gray, black to white...) so ...
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1answer
70 views

PyQGIS: feature added signal throws an error message

For my PyQGIS plugin 2.2, I try to: def logFeatureAdded(self,layerId,addfeatures): message = str(layerId) + " has features added: " for feature in addedFeatures: message += str( ...
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0answers
65 views

How to add a TIF raster layer programmatically?

This is my code whenever i try to load .tif image it shows layer is not valid,QgsRasterLayer always return invalid layer (I am using linux 12.04). QString myFileName = ...
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0answers
131 views

How to group a multiple rasters in MapServer?

I had a map files for each state (raster file) of India. Now I want group all mapfiles to show a single raster or single map file? How I can do in using qgis or any platform?.
2
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1answer
154 views

How to do a “fuzzy” intersection?

I have two layers that look like this: I want the intersection (or whatever the correct term may be) to look like this where the output polygons are the same as the original base layer, just with ...
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0answers
176 views

Merge/mosaic categorical rasters in QGIS/GDAL

I am attempting to make yearly bins of some monthly MODIS data for all of the US. The cells of the raster are defined with Julian dates indicating the date at which a burn event took place. After ...
3
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2answers
240 views

Use Values from Raster Statistics (e.g. sum of all cells) in Raster Calculator

I need to do calculations on raster layers which require the sum of all cells of the raster. I've used the zonal statistics tool for that but it gets a little annoying to do those extra steps (run the ...
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1answer
182 views

Suggestions on Imagery type for ArcGIS for Server (Without Image Extension)

I am exploring the best options to serving raster imagery on ArcGIS for server 10.2.2. As a background, I currently have roughly 200 .jp2 files of about 3mb each. All of these files are currently ...
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0answers
71 views

Developing a Slope Map of India [closed]

I am working on developing a Slope map of India (for my research), where I collected DEM from Bhuvan and tried to mosaic and then perform terrain analysis. But I am unable get the output since the ...
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2answers
194 views

Display Point Labels in QGIS

I have coordinates and points from that coordinates. so what do i need to do to show point numbers on the map? Thanks. It's my second day with QGIS
2
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2answers
131 views

How to write a (memory) layer from QGIS to PostGIS?

I am looking for an "elegant" solution to write, from a python script, a layer from qgis and into a new table of a PostGIS database. I thougth that this might be solved by QgsWriteVectorLayer, but I ...
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0answers
73 views

Is there a way to take control of the mouse pointer using python in QGIS?

i would like to take control of the mouse pointer in QGIS (for example constraining it to a given extent...) Is there any way to do that using PyQGIS ? Thanks !
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2answers
815 views

Is there a way to get Z value from 3D multipoint shapefile in QGIS?

Is there a way to get Z value/height/altitude from 3D multipoint shapefile in QGIS? All I found is way through SpatiaLite or PostGIS as explained here: ...
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0answers
35 views

Rotate polygon preserving topology in QGIS?

Is it possible in QGIS? What I need is: 1) Rotate a polygon inside another one (bigger), obviously the polygons are not overlapped. 2) Rotate a given polygon in a topologically correct layer (like a ...
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1answer
196 views

mmqgis plugin not showing up in plugin dropdown menu

I have installed the plugin from the plugin dialog box, but I am unable to figure out exactly how to run the plugin.
5
votes
2answers
144 views

CRS for submission to Minnesota DOT

Does anyone have experience using QGIS to submit shape files to the Minnesota DOT (MNDOT)? I am using EPSG:26915 but got rejected due to an error in the CRS. MNDOT Specs call for "UTM coordinates, ...
2
votes
1answer
226 views

*Value relation* widget in QGIS

I cannot understand what the Value Relation widget of the Fields menu in QGIS actually does. For example: I have a point layer with some columns (ID, value1...) and a table (so just a dbf file) with ...
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1answer
419 views

Can QGIS open a SDF file created by HEC RAS?

I used the "export GIS data" option in HEC RAS and got a SDF file. Is it possible to open it in QGIS?
3
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1answer
1k views

How to install LAS tools in Processing for QGIS 2.4?

Does anyone know were the processing menu moved in QGIS 2.4? Specifically I am trying to install the Lastools box for QGIS following these instructions. ...
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1answer
74 views

Creating a new shapefile based on an existing problematic shapefile

I have a large floodplain shapefile and would like to create a new shapefile based on coverage. I'm having major problems with the original (intersections and other errors) which I've been unable to ...
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0answers
59 views

QGIS DEM Output cell size does not match DEM input cell size

As my first post I offer a humble apology if this is such a basic question as to make any of you cringe. I feel like I have exhausted my search skills and read through the QGIS documentation ...
2
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1answer
84 views

Query DEM Elevation at Point in QGIS

I'd like to be able to pull up a DEM (or create a mosaic of them) and simply query the elevation at points I click. Is this possible using QGIS?
2
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3answers
509 views

How can I work with very large shapefiles (~1 GB) in QGIS?

I'm performing some basic spatial analyses on a large database of traffic injuries in California between 2003 - 2011. Because the dataset is large (nearly 1 GB of points), I'd like to first cut it ...
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0answers
29 views

Will QGIS fulfill my requirements? moveable, rotatable, draggable, complex, interactive icons

I'm trying to compile a list of mapping software that will fit my requirements for a desktop application I want to build. I'm trying to build something similar to MissionPlanner: ...
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0answers
35 views

Is there a Targer-like tool for QGis?

I'm trying to make subsurface drillhole and I heard that Target (an AutoCad tool) can help me with this task but the issue is that I work with QGis.
2
votes
1answer
162 views

QGIS distance from points to nearest line

How can I get the distances from each point at a shapefile to the nearest line from another? I've tried to follow the directions from Measuring the distance between lines and points in QGIS and ...
2
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2answers
911 views

QGIS Raster Calculator: Need values to be set to 0 instead of no data

I have a landcover map with different values for the landuse options e.g. 190 for commercially used areas. Now I want to extract only these areas using the Raster Calculator with the expression ...
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0answers
51 views

Tagging polygons within larger polygons (spatial join)

another QGIS newbie here. I have a number of smaller polygons which perfectly aggregate to a larger polygon. I want to "tag" the smaller polygons with the ID of the larger polygon they make up. ...
4
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1answer
122 views

In which way is height information stored in a DEM?

I'm struggling with different DEM data, because I don't know how to convert the height information in meters. When I load ASTER and SRTM tifs in QGIS, it shows me the spectrum of the grayband (0 to ...