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

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116 views

How to enable Map Tip display text in qgis and qgiscloud?

I'm using the free version of qgiscloud and qgis 2.4. I noticed that if I'll use the HTML option in "Map Tip display text", the map in qgiscloud will only show the title of the layer when I ...
3
votes
0answers
79 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
112 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.
2
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0answers
25 views

QGIS is locking the clipboard from other application? (SitesPlus)

We are starting to use QGIS along with Sales Forecasting software Sites Plus by Gravitec. An ugly problem just popped up: Whenever QGIS is open, any attempts to calculate a data table in SitesPlus ...
5
votes
1answer
224 views

Interactively determining upslope and downslope areas on DEM?

I know SAGA GIS can be used to interactively generate maps of upslope and downslope areas for a cell within a DEM, but the output is pretty ugly. An upslope area is defined as all cells (for a ...
0
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0answers
106 views

How to save a WMS layer at multiple resolutions as .tif using pyqgis

How can I export a wms-map-extent as a .tif from QGIS? Is it possible to call the "Save as.." function of a WMS-raster-layer from pyqgis? (E.g. by simulating right-clicking the layer, choosing "Save ...
2
votes
1answer
109 views

QGIS show gdal_polygonized file in EPSG:54004 instead of EPSG:3857

I am polygonizing a TIFF with the gdal_polygonize.py and the resulting Shape is shown in QGIS in the wrong projection - EPSG:54004 instead of EPSG:3857. I have a TIFF in EPSG:3857 and polygonize it ...
3
votes
1answer
87 views

Calculating distances from points to the centre of cells

I am using QGIS 1.8.0 (using older version because I need the Qmarxan plugin which is not available for 2.4.0). I have a study area that has a vector laying of "planning units", or cells over the top ...
2
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1answer
77 views

How to use inbuilt tools in QGIS Modeler?

Is it possible to incorporate inbuilt tools like, for eg: vector grid of Research tools in QGIS model builder ?
2
votes
1answer
98 views

What's wrong with my expression to control label colors?

I am struggling to alter the label colours according to field values (as strings) in the attributes table. In my mind what I want is: If the string in column X = 'Proposed' Then label the point ...
2
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0answers
79 views

How to develop a real-time navigation App using QGIS API?

I want to develop a navigation application based on QGIS using C++, for live tracking. I think it is quite normal for GIS to do such things, especially QGIS as it is a very mature GIS platform. But ...
4
votes
1answer
123 views

Is there an issue with Zonal Statistics calculating wrong mean values?

I tried to solve the following issue by myself but without success. On the one hand I have a raster file which is the result of the processing "shapes to grid" tool. On the other hand I have a ...
2
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0answers
46 views

Why does my clipped raster seem to be slightly moved?

I'm having some problems with clipping rasters. I started clipping my raster using extents, but I saw that the clipped raster is different from the original raster. I created a virtual raster to use ...
0
votes
3answers
121 views

What Open Source Packages are available to provide routing

I am looking for ways to validate mileage charged by our contractors. They are paid from a central location to a customer, and then from the customer to a drop off location. I use QGIS for a bunch ...
2
votes
1answer
101 views

Cannot load postgis layer from sql string in pyqgis

I'm trying to load a layer using the following code in qgis python console: sql = "(select the_geom, ID from mytable)" uri = QgsDataSourceURI() ...
1
vote
2answers
87 views

How can you create a depth raster from a DTM and a polygon in QGIS?

I have a DTM raster and a flood outline in polygon format - how do I create a depth raster for the flood outline (i.e. flood level minus DTM level)?
0
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0answers
43 views

How to reference a number variable in r.mapcalc within QGIS graphical modeler

I need to run the following formula in r.mapcalc: (xor(abs(A-B),abs(A-C))>120)*A I would like to however use a user defined number input variable instead of the 120. I already have this variable ...
3
votes
1answer
52 views

In QGIS, is it possible to save graduated styles to use on different columns? [duplicate]

I'm using QGIS to produce thematic maps of 9 quantities (given in 9 columns in the attribute table) which have values broadly within the same range and I would like to plot them using the same ...
2
votes
2answers
73 views

kml does not overlay correctly in QGIS

In QGIS, when I insert a kml contour that was created in Google Earth, it appears misaligned in respect to all the other layers. Note in this image how the red contour is moved upwards with respect ...
0
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0answers
48 views

insert row into postgis query table in QGIS

I find I am using QGIS (2.4) more and more as a client for PostGIS database tables with geometry, but also for tables without geometry, partly because it's good just to use the one application and ...
2
votes
0answers
84 views

How to design labels which look like a fraction (with a fraction line)?

I want to create labels like a fraction using data from two columns. I have tried to use: "Field" || '\n' || '――' || '\n' || "Field2" but it doesn't look good. How can I do it using other method? ...
2
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0answers
37 views

Creating Form in QGIS

I want to create a form for editing attributes in QGIS. I have a lot of question and hope somebody can suggest how they work or where I can read about the next elements of form: Classification List ...
1
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0answers
63 views

How to create a svg item onto Map Canvas in QGIS API?

I'm working on a project with QGIS-2.4.0 API using C++. I need to load some svg files to the application for displaying as symbols. QGIS API has a class named QgsMapCanvasItem, which is an abstract ...
2
votes
1answer
179 views

Setting up QGIS Server at low cost for small user community?

I want to setup QGIS Server at a low cost for a small user community (mainly me). Parameters: Some data is private so something like qgis cloud not an option (not enough money for paid option). ...
1
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1answer
68 views

How to use bold text in QGIS font marker symbol?

Is it possible to use bold text with the Font marker symbol in a QGIS (point) layer?
0
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2answers
91 views

How to style graduated using size-scale field

Is it possible to style based on size-scale field using graduated symbol but instead of using color ramp, I would like to display its size. I would also like to display this in the legend in the map ...
3
votes
1answer
128 views

Dark Object Subtraction QGIS

I'm trying to do Dark Object Subtraction (DOS) for a Spot2 and 4. I have calculated the TOA reflectance and now want to get the at surface reflectance. Using QGIS I would like to know how I can do ...
1
vote
1answer
131 views

What's the reason for this Invalid Layer “Cannot open GDAL dataset …” error

When adding a rasterfile with QGIS python console there appears an error when the first letter of a rasterfile to be added is not written in capital letters. Why this behaviour? Example case1: ...
2
votes
1answer
33 views

How to store a password during one QGIS work session?

I'd like to get into qgis-plugin development, but am rather new to both python and QGIS development. I intend to write a plugin which connects data from a mysql database to shapefiles. As the data is ...
3
votes
2answers
43 views

QGIS doesn't create the correct projections when creating new shp files

I received shapefiles exported from ArcGIS with EPSG:2227 as the CRS, which should be: +proj=lcc +lat_1=38.43333333333333 +lat_2=37.06666666666667 +lat_0=36.5 +lon_0=-120.5 +x_0=2000000.0001016 ...
9
votes
0answers
156 views

How do ESRI and QGIS calculate scale values of geographic projections? [closed]

Does anyone know how (from which location) scale values are calculated in ESRI products and QGIS for geographic projections? The only thing I've noticed is that QGIS is changing scales when you pan ...
3
votes
2answers
342 views

How to calculate the square root of a feature attribute?

I have a polygon shapefile with over 16k features. Each has an attribute (Double, Precision(10) Scale (2)) that I am trying to calculate the square root of, and store in new field. Is there a tool, ...
1
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0answers
29 views

Can HTML annotations be autogenerated for each location in QGIS 2.4

Can HTML Annotation Boxes be autogenerated on the whole map, linked to locations, and always have the same html file loaded for all of them?
1
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2answers
73 views

Creating counties in QGIS

I have a raster map (a photocopy I took from an Atlas), and a vector map of the UK. The raster map shows pre-1890 Scottish county borders. I have geocoded the map so that the raster borders overlap ...
1
vote
1answer
111 views

Reprojected Shapefile does not align with Openlayers Plugin [closed]

I am based in NSW, Australia. I have a shapefile that when I underlay with the openlayer plugin (google satellite), the shapefile is skewed despite all my efforts to correct it. I changed the ...
0
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0answers
19 views

unable to open the QGIS Tab

I have download the QGIS Softarwe of “gis-osgeo4w-1.7.3-00624b3” and “QGIS-OSGeo4W-1.8.0-2-Setup” both from net and installed both in my system, My system is running window07 professional Service ...
1
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0answers
20 views

QGIS Equivalent of MapInfo's 'Combine Objects using Column' [duplicate]

MapInfo has a function that takes a table, and creates a new table populated combines them by a specified value. So, combining on the name field, and specifying that the Area field should be ...
3
votes
1answer
320 views

Adding an “m” to the end of every number in a row

What function do i need to use to add an space and an m after every item in a row, using the field calculator in the attributes table. I have a load of numbers (as strings) and would like to add m ...
0
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0answers
44 views

Splitting existing polygons with existing polylines(roads) with GME tool “split polygon by lines”

After reading through many of these articles i believe the GME tool "split polygon by lines" should be useful to my problem. I have a polygon that needs to be split by a road layer. When i run this ...
3
votes
2answers
195 views

Converting huge multipolygon to polygons

I have a shapefile with some huge multipolygons, with 100.000's of parts. What would be the easiest way to split them to singlepart polygons? I'm looking for something like QGIS ”Multipart to ...
1
vote
0answers
61 views

Why a shapefile of a geological map is not the fault lines are displayed in QGIS?

I am a new user of QGIS 2.4. I do not display correctrly geological SHP layer. This shape contains polygons with shapes, fault lines, dips, volcanic structures, shoreline types, geological boundaries ...
0
votes
0answers
14 views

Make the foot of the histogram coincide with the point in QGIS

Is it possible in case of histograms in QGIS to make the foot of the diagram appear above the point or always make them appear above. My issue is that I see the option that maked them appear around ...
1
vote
0answers
111 views

Unable to access R from QGIS 2.4

I have been unable to run R from within QGIS on my computer. I have R version 3.03 installed and QGIS 2.4 on Windows 7. R is located at C:\Program Files\R\R-3.0.3\bin\and this is the path e specified ...
2
votes
1answer
72 views

QGIS Intersection problem

The QGIS Intersection tool is not working for two shapefiles in Version 2.2 or 2.4 (haven't tried earlier versions). I get a new shapefile with all the attributes, but no features. However, when I use ...
2
votes
0answers
21 views

QGIS WEB Cliente para windows 7

Bom dia, estou com alguma dúvidas a respeito do QGIS WEB Cliente que não consigo achar uma solução. Eu sei que tenho que fazer a instalação do Qgis Serve como esta escrito neste tutorial Anita Graser ...
1
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0answers
43 views

Is there a way to automate POI collection from websites?

I am searching for an easy method to get lots of points geotagged/georeferenzed into several shape files. I am working at a project where I need to collect all parcel shops in germany (but I will try ...
0
votes
1answer
72 views

QGIS Python console - save image from bounding box

I want to save an image from QGIS but the save image functionality feels limited. My question is if it's possible to use the python command line to save an image at a specific zoomed in scale and to ...
1
vote
1answer
43 views

pyQGIS - Data Source is Invalid

Why I am getting Data Source is Invalid in python console of QGIS when running: vlayer = QgsVectorLayer("home/sanjayr/Desktop/india-latest.shp/buildings.shp","sanjay","ogr") I am using QGIS 2.4 on ...
3
votes
0answers
62 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 ...
2
votes
1answer
67 views

How to convert unix time to qt time type?

How can I convert unix timestamp to qt time type using qgis field calculator? I would like to avoid importing my table into excel and convert the timestamp to qt time type.