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

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2
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1answer
59 views

How to get into the Python API of QGIS?

After a few hours I am about to give up on finding a kind of documentation for the QGIS Python API that actually works/gives the correct information. It is obvious that there is no actual code ...
1
vote
1answer
29 views

QGIS raster calculator using abs() function

Is it possible to use the Abs() function in the raster calculator in QGIS? I've tried it, but it didn't work.
1
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0answers
25 views

Cannot produce pie chart in QGIS 2.2

I have a shapefile to which I joined two tables from a MySql database. I used one column of the first table to color the polygons in my shapefile which works fine. Three columns out of the second ...
1
vote
1answer
69 views

How to convert float to raster in QGIS

I have downloaded bathymetric data into QGIS. In order to use it I need to conduct a float to raster conversion. I have not been able to find how to do this on any of the forums. I have unsuccessfully ...
1
vote
0answers
32 views

QGIS processing framework SAGA NaturalNeighbor in external Python Script - No Output

I want to build a little script, which generates a NaturalNeighbor grid based on a point Shapefile. The script runs within my PyDev environment without any error messages, but no outputfile is ...
0
votes
0answers
21 views

GDAL_Translate not compressing when NoData value is set

I am trying to compress a .TIF file using GDAL_Translate or GDAL_Warp. My Raster is 32mb to start with. When I use GDAL_Translate with the COMPRESS=PACKBITS option, it compresses to 1.9mb. However ...
2
votes
2answers
124 views

How to calculate area of shapefile with a merged layer

so i have 'save as''d the new project and layer with my new Custom CRS project string being '+proj=laea +lat_0=70 +lon_0=0 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs'. ...
0
votes
0answers
33 views

QGIS 2.4 How do I find and change measurement units? [duplicate]

I want to create 1,000m buffer around an object, but when I enter 1,000 as the distance I get something that looks more like a 100,000m buffer. I can enter 0.01 to get what looks like a 1,000m ...
0
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0answers
38 views

Specifying which fields in SQL Server table are lat/longs using QGIS?

I have successfully connected my MSSQL DB to my project and I am trying to add a layer to represent the data in a table. I want to make a density map using the lat/longs that are stored in two fields ...
0
votes
0answers
15 views

Calculation size limit to creating distance matrix using QGIS?

I have a shapefile of postal code for a city (Montréal). I would like to calculate the distance between all postal code. I tried to run the distance matrix after converting all postal code to a ...
0
votes
1answer
22 views

Can't save map with different projection in QGIS

I'm using QGIS 2.4 and am opening a shapefile I downloaded (specifically from: http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/110m/physical/ne_110m_coastline.zip). What I ...
7
votes
1answer
82 views

Adding Route Shapefile (PolylineM) to QGIS?

I'm new to QGIS (and to this amazing forum as well) and I already have an issue : I received a Route Layer in SHP format (PolylineM). I've easily loaded this file into QGIS but it doesn't seem to ...
2
votes
2answers
129 views

Exporting 16 bit single-band to 8 bit in SAGA/QGIS

Everytime with every function (e.g convert data storage type or gdal-translat -ot Byte) the output is a completely white map with a black border. only the "save as" export works, but the TIFF also ...
2
votes
2answers
70 views

Any idea how to export multiple KML files from one SHP layer?

When exporting one KML, it's exceeding the Google Fusion Table's max limit of 100mb per upload. Fusion Tables however lets users merge more than one KML for a merged max size of 250mb. Any idea how to ...
0
votes
1answer
21 views

Is there a way to use old Print composer templates in 2.0?

As the title says, the old templates do not work in 2.0. It started with having to redraw boxes, now it causes it to crash completely. Is there an easy fix. Can i download templates for use??
1
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0answers
47 views

Qgis Web Client feature jump to layer

It is possible to add a new feature to qgis web client? I would like to add jump/zoom to selected layer. I tried to add something like this using ZoomToExtent feature with fixed coordinates, but this ...
1
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0answers
23 views

Create “grid” of polygons with the same 3D area based on an underlying raster variable (e.g. DTM height)

This could apply to point or raster values but imagine a raster of a continuous variable such as height (DTM). Is there a way to create a complete coverage of polygons that will have an equal area, ...
1
vote
0answers
42 views

Is there a QGIS plugin that allows users to interface with a PHP form page?

I've been looking for several days for a QGIS plugin that allows users to interface with a PHP form page. Does anyone know something that works in this way?
3
votes
2answers
183 views

Overlaying polygon filled with solid colour with diagonal lines in QGIS

I'm making a vegetation survey map using the UK phase 1 survey colour codes. The code for marshy grassland, for example, is orange overlain with purple diagonal lines. For the moment I've created ...
2
votes
2answers
66 views

Select part of a polygon on one side of a line QGIS

I have a line shapefile of the outline of a water body. It was created by conversion of the polygon to line. I am looking to add a layer of 500m standoff from the shore into the lake. I have added ...
2
votes
1answer
72 views

Creating points from lines with length and rotation fields using script in QGIS?

I'm about to create a script wich creates points from lines on a specified layer with a length and a rotation field. Geometry: The point goes to the first vertex of the line Attributes: length ...
1
vote
0answers
30 views

How to get a dynamic picklist in QGIS

Has someone an idea how to get dynamic picklist widgets in the object window! Eg. You choose a country in a picklist so the next picklist only shows cities in that country! I know that you could ...
2
votes
1answer
81 views

How to import Excel data and display it on a state map in QGIS?

I want to import summarized data from Excel into QGIS 2.4. The date consist of US states and Canadian provinces paired up with a percentage. The data looks like this: State % CO 50.4 IN ...
0
votes
1answer
29 views

Any consideration of moving QGIS project file to SQLITE form XML? [closed]

Just curious, has anyone ever proposed storing the ".qgs" project file in SQLITE instead of XML? Seems like it might be faster, easier to parse, and you could hide the changes behind an API. But I ...
1
vote
0answers
42 views

Error when trying to visualize geography data with QGIS

I use PostGis, and want to use QGIS to visualize data. But I get error message when trying to show the points in the table. I create a table: CREATE TABLE poi ( id text NOT NULL, coord ...
1
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0answers
59 views

How to build QGIS on CentOS?

I'm trying to install QGIS, without success. I install all dependencies, but the compilation still sucks. My compilation log : [root@localhost build]# cmake .. -- QGIS version: 2.4.0 Chugiak (20400) ...
1
vote
1answer
27 views

Spatialite error: obsolete libspatialite

I am learning to use QGIS with the QGIS training manual (from the QGIS website). One of the excercises is to load vector data from a database (ch 3.1.3 in case you have the manual). When I try to do ...
3
votes
2answers
60 views

Unknown red rectangle appears in map window

I would like to know where this red rectangle comes from? It's not a polygon or a line, it can't be activated or removed or anything else. It just appeared during the project work (adding shp-files, ...
2
votes
1answer
24 views

Adding point data from text file when coordinates are in OSGB36

I have a text file in which coordinates are in the OSGB36 National Grid reference system used in Great Britain, so the coordinates are not in longitude and latitude (e.g. coordinates look like this: ...
3
votes
0answers
31 views

Find Polygon in “Layer A” containing Polygon in “Layer B”

I haven't found yet someone with the same problem, so I'm posting a new question. The topic seems quite standard, so I'm sure there's a way to do it in QGIS. I have two layers: Region Layer Postcode ...
0
votes
0answers
14 views

Update points in polygon

I want to update a column in point layer (sqlserver) where points are within a certain polygon. I want to use QGIS for this. Best regards Chr.
6
votes
2answers
331 views

What is the difference between Create Thiessen Polygons tool (ArcGIS) and Voronoi Polygons tool (QGIS)?

Is Thiessen polygons the same thing as Voronoi polygons? I am using ArcMap 10 and also QGIS 2.4 and I would like please to know the exact difference (If any) between the two methods.
1
vote
1answer
47 views

Is it possible to create a GPS track in QGIS and if so, how? (beginner question)

I'd like to use QGis as a trip planner. Once there's a topographic map on the screen - from whatever source - I'd like to point-and-click a track over that map, then export it in a common GPS format ...
1
vote
2answers
95 views

Export polygon in geojson as multipolygon

Anyone knows if is there any way to export a polygon layer in geojson, as multipolygon? I have a multipolygon shapefile. But there are single and multi polygons. When I export it to geojson, I got ...
1
vote
1answer
19 views

Find Polygon in “Layer A” containing Polygon in “Layer B”

I haven't found yet someone with the same problem, so I'm posting a new question. The topic seems quite standard, so I'm sure there's a way to do it in QGis. I have 2 layers: Region Layer Postcode ...
2
votes
2answers
31 views

Custom projection problem with proj.4

I have some vector files that come without projection. So I have to define my own projection in QGIS. The information that comes with the data reads as following: Projection: Lambert Azimuthal Units: ...
2
votes
1answer
66 views

Import MySQL data to QGIS with a plugin

Does anyone know about a plugin that can import a MySQL database into QGIS?
4
votes
4answers
120 views

Create a rectangular buffer from point shapefile using QGIS/GRASS/SAGA GIS/R

I have a points shapefile and I want to create a rectangular buffer (22 x 16 km) around each point. My goal is to create a 16x22 km grid where each of the points is the centroid of the grid. Seed the ...
2
votes
0answers
16 views

QGIS view selected layers, manage views

I have a QGIS project with a large number of layers. Is it (without using Postgis) possible to define "Views" which include different subsets of the layers? For example: View 1: Layers WMS ...
2
votes
0answers
25 views

Extracting gridded data from polygon vector layer

So I've spent a few enjoyable (and frustrating) days teaching myself the basics of QGIS and fiddling around to try get some data output I need to drive some calculations. Sadly I'm not having any joy ...
2
votes
0answers
32 views

How do you create either a geotiff or a .tfw in QGIS using python?

Probably I just don't understand the API documentation, I don't use object oriented programming to its full capability. I do see this has to be done from a composer object in order to automatically ...
1
vote
2answers
44 views

Turning Polyline with Multiple Segments into One Single Line

Using QGIS Valmiera (MapInfo and other software is also available) Is there a way to convert a polyline with multiple segments into a single line? I.e. by taking the first point and the last point of ...
1
vote
0answers
33 views

Error on 'Extract raster values to CSV' in batch process in QGIS

The Extract values (csv) contained a bug in the script. The below link shows how to correct the bug. Error on 'Extract raster values (CSV)' - Error executing algorithm 1 'Dataset' ...
2
votes
1answer
34 views

How to write a custom canvas item for SVG marker by subclassing QgsMapCanvasItem in QGIS?

I want to subclass QgsMapCanvasItem for SVG marker in QGIS, I looked up a similar topic in stackexchange and QGIS mailing list, I found that this is similar to mine, I did exactly what @Nathan W did. ...
2
votes
1answer
33 views

Displaying Grid line on QGIS Print composer?

I am using QGIS 1.8.0 Lisboa. I am making a print composer map that displays the grid lines as reference for the coordinates. But it doesnt display anything (gridlines) on the print composer map. ...
2
votes
0answers
33 views

Automatic generation of equidistant points inside a polygon in QGIS?

I'm trying to find a way to generate a layer of points inside a given polygon of, for instance, 100 m x 600 m. Every points must be distant from the others and from the polygon borders of (e.g.) at ...
1
vote
0answers
44 views

What kind of methods are most commonly used to interpolate a relief?

I have got a topographic plan with height measurements which I converted to point shape file with height value in attributes. I was wondering, what kind of methods are most commonly used to ...
2
votes
1answer
58 views

Why are my DMS points plotted way off from their true locations?

I'm having a bit of a nightmare plotting some GPS coordinates in QGIS. My coordinates came from a PDF so it took a little wrangling to extract the from the PDF and convert them to a CSV file. I've ...
1
vote
1answer
38 views

QGIS attributes pop-up window is empty

I have a problem with QGIS (2.2 and 2.4). Sometimes, when I'm going to insert some new features on a layer, the pop-up window that appears at the end is empty (all gray, no attributes are displayed). ...
0
votes
1answer
105 views

OpenLayers does not appear in the QGIS plugin menu [duplicate]

I have installed the OpenLayers QGIS plugin, which features external map layers in QGIS. Quoting the official page: OpenStreetMap, Google Maps, Bing Maps layers and more In QGIS, it seems that ...