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

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0
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13 views

Updating a column in MapInfo based on Symbology or colour

I am transferring a large dataset from MapInfo (V 12.0.2) to QGIS (V2.8.1) and I want to be able to create a column in the MapInfo attribute table that differentiates features with different ...
0
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0answers
2 views

Problem with the rendering of SVG for layer symbols

I have a little problem with the rendering of SVG for layer symbol. I want to creeate a categorized symbol to show different style of buoy I have for that two icons the first is an half circle ...
0
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3answers
25 views

Grass toolbar for QGIS 2.10

I don't see the GRASS toolbar in QGIS 2.10 (Pisa). There are still GRASS commands in the Processing toolbox. I know there was some upgrade of GRASS for 2.10. Is the toolbar not available anymore? If ...
4
votes
2answers
51 views

How to run qgis scripts in parallel across remote server(s)

I have a stand alone python script using qgis that I wrote with the help of the SE question here The script takes three arguments being; an input file path, an output file path, and another input ...
1
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1answer
370 views

Export to Open Layers plugin doesn't work with Raster and WMS

i am trying to export a Qgis_2.4 project to openlayers using the "Export to OpenLayers" plugin. I cannot export raster layer. I am not getting any error message, but the raster layer doesn't appear ...
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0answers
13 views

Why do pixel (cell) values change for 32 real NDVI values when taking from Multispec to QGIS?

Landsat 5 values change from normal NDVI -1 to 1 when created in Multispec as a 32 bit signed data image. When adding the raster layer in QGIS, the value range changed to 0-255. How does one ...
0
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1answer
10 views

Opening MapInfo .TAB file containing text objects in QGIS?

Whenever I try to open a MapInfo .TAB file that contains text objects in QGIS, the text objects are converted to point objects. Any help, please?
0
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1answer
30 views

Loading Natural Earth *.prj file into QGIS 2.10.1?

I have found solutions for this problem in other versions of QGIS, but none that apply to the newest version 2.10.1. Whenever I try to import a Natural Earth Raster projection that is a prj file I get ...
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0answers
6 views

How get PostGIS DB name from QGIS layer

I'm writing a custom Processing script that needs to know which database connection a vector layer resides in. I can't find anywhere in the API a function to return this information from a layer. So I ...
0
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0answers
23 views

QGIS 2.10.1: Unable to stylize as pseudocolor render type

In a raster layer's Style Properties, I can choose pseudocolor render type, and choose a color ramp and classify the raster. However, when I click the 'Apply' button, or click 'OK', the ...
2
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1answer
13 views

Inserting image in an attribute table in QGIS Composer?

I'm trying to create second page of map atlas. In this page I need to show all records in the range of current atlas page. I've used Insert Attribute Table tool in composer and it worked. But I need ...
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2answers
16 views

How to put a frame around a legend using QgsComposerLegend?

I can already see this being a simple answer but I'm stumped with this. I want to create a frame around a legend created by a PyQGIS script Code snippet is: legend = QgsComposerLegend(c) ...
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0answers
11 views

QGIS.How to load a style from POSTGIS in PyQt

The thing is that I have four styles I have created in QGIS trough the GUI and saved into a postgresql database. I can see them in the table named layer_styles I have seen similar questions asking ...
3
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0answers
43 views

Soft edges for interpolation output

I've built the following heatmap using QGis 2.8.2's Raster->Interpolation feature. It looks almost the way I want: The background layer is Google Maps tiles by using the OpenLayers plugin. ...
1
vote
1answer
24 views

QGIS2WEB Plugin (openLayer3) for QGIS not exporting raster images

I am using the QGIS2WEB plugin for QGIS. I have added vector features as well as a raster image (.tif or .ecw) format. When I try to export the webmap, all the layers are visible expect the rasters. ...
6
votes
1answer
107 views

How to create an Atlas based on point attributes?

Essentially I am wanting to produce an atlas based on a categorical field in a point layer. i.e. I have a point layer of childcare providers with the categorical field "Provision". I've categorized ...
5
votes
5answers
580 views

How to create a label formatted like “ 1,000' ” from a numeric field?

This question builds on a previous question I came across at gis.stackexchange: How to easily edit attribute data using Regular Expressions? Perhaps someone can point me in the right direction? I ...
1
vote
1answer
340 views

QGIS Invalid object name 'geometry_columns' QODBC3:Unable to execute statement

I was using Lisboa 1.8 with SQL Express and tables with geometry. Connections were working with 1.8 and are working with ArcGIS, so I know my tables and geometry are fine. I installed 2.4 Chugiak, ...
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0answers
14 views

how to make rectangle selection by mouse on my map(world shape file) in qgis in python

I want to make a rectangle selection using the mouse on my map (world shape file) in qgis in python and extract the lat lon of the selection area but I don't understand how to do it. I don't have any ...
5
votes
4answers
224 views

Is there a quick way to clear all attributes from a layer but leave the polygons in place?

I have a layer with several polygons, each of which has data in over 100 fields. I need to create a new layer with all the same polygons, but with all their data fields blank (set to 0, Null or empty ...
0
votes
1answer
19 views

How can I check in QGIS python if an atrribute is included in my layer?

I use the following code: for field in self.layer.pendingFields(): if field.name()=='elevation': do this else: do that Although there is an elevation attribute in my layer ...
4
votes
1answer
103 views
+50

Creating disease risk map in QGis

I would like to create a risk map using RFE Data and Tiffs but now I realised that I actually have no idea how. I have dowloaded .Tiff(Region), .hdr and .bil(Rainfall/RFE) files from the USGS page, ...
2
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2answers
3k views

How to access attribute data type in QGIS?

I've been developing a plugin on QGIS platform using PyQGIS. So far plugin does the following: You can select any feature of the already loaded vector layer in QGIS. After selection, plugin displays ...
2
votes
2answers
959 views

Calculate area covered by a particular raster layer within polygons in QGIS

I am trying to extract information on vegetation cover within a set radius of point locations (my sites). I have succeeded in creating a new vector layer of circles with a 5 km radius around my sites. ...
1
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0answers
43 views

Create Indexes Within a View? How could I Speed up Spatial Queries Over a View?

I´m trying to add a view from postgis using QGIS, what´s facile. The problem is that it´s taking too long to load it and to perform any kind of operation, for example, as simple as counting rows. It´s ...
1
vote
1answer
24 views

what is the “clip” feature for color ramps?

In the singleband pseudocolor band rendering, there is a boolean checkbox "clip". What does this do? I don't notice a difference in my maps and haven't found documentation for it. Thanks
4
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2answers
188 views

Boundary from Points

I have a point cloud and need to process a very detailed boundary around the outer points. Is there a tool in QGIS? Convex hull is not detailed enough. Thank you!
2
votes
1answer
21 views

QGIS: Finding electric network loops

With QGIS, how can we analyse an electrical network to find loops? Using Python is not a problem, however there is not a solution in the QGIS Python API. The QgsGraphAnalyzer has dijkstra and ...
0
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0answers
13 views

Problem using EPSG:3395

in my application I use OGC:CRS83 for the coordinatereferencesystem, but now I had to change it to EPSG:3395 when I call : mQgsCoordinate->createFromOgcWmsCrs("EPSG:3395") there is nothing in ...
2
votes
1answer
22 views

QuickOSM returns no result

I am trying to download the polygons for the Umweltzone Heidelberg from OpenStreetMap using QuickOSM in QGIS. I queried by name as shown in the screenshot: The corresponding OSM script looks like ...
0
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0answers
9 views

Unable to make qgis build in cmake

I am trying to build qgis without any change in source code which i have downloaded from github using clone and i have download OSGEO4W from qgis.org and the same is installed in c drive. I have ...
1
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2answers
61 views

One-to-many join in QGIS

I am looking for a possibility to make a one-to-many table-join in QGIS. I have a shapefile with postal codes and would like to join them with survey results (more than one). In other words, there ...
0
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1answer
21 views

What is the meaning of DN and DRVAL2 categorie?

I try to find the meaning of the categories DN and DRVAL2 when I used them in the command: lrenderer = new QgsCategorizedSymbolRendererV2("DRVAL2" , Categrories ); Is there any tutorial or ...
1
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0answers
17 views

Error in Editing Point Shapefile: I can't add a new point feature

I want to add a point to a point shapefile. I place the cursor in an empty field. The strange thing is that the point of the point shapefile that is nearest to the cursor is highlighted. If I click ...
8
votes
3answers
942 views

Can QGIS Read Spatialite Views?

I have a spatialite database I created that spans several years of crime data. To facilitate a real-world scenario where I may simplify the interaction for a user by introducing a View that simply ...
11
votes
1answer
2k views

How to create desire lines in QGIS?

How can I show the flow coming from an Origin-Destination matrix as desire lines? I need a result like the one in the picture below. I need to scale them proportionally to its value (coming from a ...
0
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0answers
25 views

QGIS version migration of Styled Layer Files

I have a stand alone application which reads SLD files, to draw something on a map canvas (development started under QGIS version 2.0.1). Unfortunally I have to deal with these old SLD files version ...
1
vote
2answers
27 views

QGIS 2.10.1 (64bit) rotation field setting missing

I cannot find the the rotation field setting under the properties-layer settings-advanced (for styles) menu in the new release of QGIS (2.10.1 64bit). The only setting what is available there is the ...
2
votes
0answers
27 views

How to rename field names in a shapefile attribute table without table manager using python

By using the table manager we can rename the field names but i want to rename of fields using python. How can i do that?
2
votes
1answer
24 views

How to break a closed line when intersect with polygon

I have a number of polygons (in lines shape) which represent the new condition of an area and a numder of polygons (in polygon shape) which represent the old condition of the same area. How can I ...
1
vote
1answer
26 views

How to render the Sea depth level in different color?

I would Like to adapt an old code in c++ using the api qgis 1.6 : const QgsRenderer* lrenderer = pLayer->renderer(); if( lrenderer == NULL ) lrenderer = new QgsSingleSymbolRenderer( ...
1
vote
1answer
21 views

QGIS Print composer dynamic labels

I have created an Atlas. One of my layer contain height restriction for bridges. I wish to create a label that show the lowest height restriction. I need to get the height values from my table that ...
1
vote
1answer
15 views

How to read non-spatial data using PyQgis?

I'm generating maps with QGis. What I do is generate a bunch of non-spatial data on a set of cities (using VBA), and still using VBA, generate a python code that will automaticaly output general map ...
0
votes
1answer
15 views

GPS points of a vehicle snapped to a specific polyline path [duplicate]

So I have been capturing bus GPS locations for a while now, and I am became interested in snapping them to their corresponding polyline (route). While at first this seemed like an easy enough task I ...
1
vote
1answer
39 views

Orphan road segments

I am working with OSM road data for a developing nation. Included in the dataset are various small networks of roads that are orphans or islands i.e. not connected to the main road network. For ...
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0answers
14 views

Has there been any further development in the integration of QGIS plugins to Processing Modeler? [duplicate]

I have read that there is no ability to use QGIS (2.8) plugins when building a model in Processing Modeler. All of these posts were a few years old so I was curious if there was any development or ...
1
vote
1answer
17 views

How to Convert Just a Sulawesi Map to Leaflet

I'm still develop a Web GIS that show population distribution in form of heat map. I'm use Quantum GIS with Open Street Map & Q2Leaflet Plugin as a tool to accomplish it. The problem is, I just ...
1
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0answers
40 views

Repeated GPS coordinates in data are creating stacked points on map in QGIS

I have 30+ events of data collection for each GPS location (previous person on project has simply added new rows for each data collection period). When I import the excel file (via CSV format), each ...
2
votes
2answers
1k views

Different NoData values when processing a GeoTIFF in QGIS and bringing it to ArcGIS

I'm trying to process a GeoTIFF in QGIS 1.8 using SEXTANTE and GRASS via the r.neighbors tool. I'd like to process the image, then be able to utlize it in ArcGIS. The problem I'm running into is ...
1
vote
2answers
47 views

How to sum values of overlapped pixels in thousands of rasters layers and clip it using a polygon in QGIS?

I have a lot of rasters files (more than 6000), each one represents the presence and absence of a species (1 for presence and NoData for absence). The set of rasters covers the whole Latin America ...