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

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7
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4answers
4k views

How to convert raster to point in QGIS

I wanted to convert Raster into Point Vector in QGIS. Is it possible? QGIS have option to convert it into polygon but i didn't found any tool to convert it into point. can anyone help me?
0
votes
0answers
44 views

How to perform Visibility Analysis using QGIS? [duplicate]

How can I calculate Visibility using QGIS? I have not found any suitable plugins for QGIS to do this.
2
votes
1answer
125 views

QGIS; Is it possible to show layer name in attribute table in print composer?

When adding attribute tables in the print composers it is not possible to distinguish between various tables from various layers; each table is generic and does not indicate which layer the table is ...
0
votes
1answer
74 views

Setting up Raster Calculater for QGIS Python Console: ImportError?

I'm trying to follow the instructions here How to evaluate raster calculator expressions from the console? to set up the python console to to use the raster calculator. I tried: from qgis.analysis ...
1
vote
1answer
465 views

QGIS raster calculator “not equal”?

Is there a syntax for "not equal" in the QGIS Raster Calculator? If so, what is it?
2
votes
2answers
454 views

Editing vector data over the net: WFS or PostGIS?

I'm using QGis to update the attributes of a large vector dataset (~20,000 polygons) stored in PostGIS. I'm going to have to do that to other large datasets so the idea is to bring in more people, ...
3
votes
2answers
230 views

Why can't I open a .xls with QGIS in OSX?

I'm trying to open an .xlswith QGIS 1.8 in a Mac, I'm loading the vector layer from Add new vector layeretc. etc. the procedure works in Windows but not in Mac where I have an error Invalid source ...
2
votes
2answers
955 views

installing older version of QGIS on Ubuntu

I recently installed the latest version of QGIS (2.0) on my UBUNTU 12.04. But am not very satisfied with it. I would like to uninstall it and reinstall QGIS 1.8 v on Ubuntu. Am unable to do so. It ...
1
vote
0answers
36 views

Map algebra from QGIS python console? [duplicate]

What command do I use to do map algebra on rasters from the QGIS python console?
1
vote
1answer
70 views

Problem about exporting the project

I'm working on a project using QGIS. I have 3 layers in the project, city boarder, the location of the natural monuments, and a layer as background card. I am going to have these three layers in my ...
0
votes
1answer
198 views

Problems installing the Astun Technology Loader in Windows 7

I previously asked a question Using OS Mastermap SLDs in QGIS I got several answers suggesting that I use the Astun Technology Loader. There are details on how to do this ...
11
votes
1answer
826 views

PyQGIS file lock release

I was wondering what triggers the release of file locks in pyQGIS? I am trying to delete a few data sources (used temporarily) by calling QgsVectorFileWriter.deleteShapeFile, but I have to quit QGIS ...
0
votes
1answer
519 views

How to check if REST plugin is installed for GeoServer

Hi I am having trouble uploading vector files onto GeoServer 2.4 using 'Import Vector' in the QGIS Processing toolbox. After reading around about the 'REST' plus in I went to: http:// Also when I run ...
0
votes
1answer
663 views

Using CASE expression in QGIS data defined properties

I try to use CASE expression in my data defined properties, like this: CASE WHEN "ASULKM1999" > 100000 THEN 5 END ASUKASLKM is population information and "5" will be size of point symbol. ...
0
votes
0answers
225 views

How to use relative path in mac for open internal and external file?

I would like that my project would be portable, I mean that I can share it without lose all the path I have in my project. This seems not so easy and many times I have to re-set all the path when I ...
0
votes
0answers
119 views

Doubt in Field Calculator

I am working in an project.I have a point Shapefile its projection is NAD83(HARN)Pennslyvaniasouth(ftUS)*EPSG3365* when I measure its distance(between two points) it gives me the answer in feet .yes ...
4
votes
3answers
2k views

How to change layer transparency without changing border lines?

I have a raster image of elevations. I have added a vector shapefile that contains local political divisions. I want to keep the elevation colors, but I want to keep the black lines representing the ...
1
vote
2answers
273 views

How do I Fix Projection Issues in QGIS

I have some exiting shape files that supposedly have a CRS of OSGEO:41001. If I import new data, and set the CRS to OSGEO:41001 they do not align. If I change the CRS of the new layers to ...
6
votes
1answer
2k views

How to transfer styles from QGIS to ArcGIS?

We have a QGIS project that has symbols for a lot of different lines. Data comes from a geodatabase that is accessible to both QGIS and ArcGIS. We now want to use the symbology of the QGIS project to ...
0
votes
1answer
58 views

Is the rule-based styling not supported on the server?

I have been using the rule-based option to style some of the layers (from a postGIS database) in my qgis project. Then I put the project on the server and when I checked the WMS connection in QGIS, I ...
2
votes
1answer
3k views

Saving vector layer with specific symbology using QGIS?

I am creating a polygon feature layer with soil classes in QGIS. I need to share this layer with some colleagues and I need the layer to maintain the color ramp I have created. Is there any ...
2
votes
2answers
532 views

QGIS 2.0 Atlas Generation: Can I force the selected feature to be the last one rendered

I have a layer with a number of features that represent zones which share some boundaries with others. I am using Atlas generator to produce a set of maps, one for each zone extent. The zones are ...
2
votes
2answers
346 views

Merge point features within a given radius [duplicate]

I have a file in QGIS with 5000 points. Some of the points are really close to each other (5m). How can I cluster the point features to one point feature if they are within 5m? The new points should ...
0
votes
0answers
109 views

QGIS, SpatiaLite and GPS integration

I have QGIS an, access database and a Haicom gps all connected and running on a windows 8 machine. I want to integrate all 3 items so that while in the field i can enter information into the ...
3
votes
3answers
3k views

How to resize the map item in QGIS print composer without changing scale?

Is it possible to lock the scale in the QGIS 2.0.1 print composer? Every time I resize the map, the scale is adjusted. This makes trying out different map layouts really annoying.
1
vote
2answers
649 views

Calculate logarithm of a raster?

I'm trying to calculate the logarithm of each cell in a raster. Is there a way to do this with F/OSS GIS? gdal_calc.py only has basic operators and the QGIS raster calculator feature doesn't seem to ...
3
votes
2answers
381 views

Calculate distance in QGIS, wrong geographic projection?

I'm trying to do the following: I have 2 shapefiles, one containing all the public schools in NY, another one containing the hotspots in NY (both in points form). Now what I'm trying to do is ...
1
vote
1answer
346 views

How to get the direction raster from r.walk or r.cost

I am trying to use r.cost and r.walk and r.drain to calculate the shortest path from an archaeological site to the nearest basalt source. I am using all this algorithms with the processing toolbox (I ...
2
votes
1answer
889 views

How to create a symbol with graduated marker size and line width in pyQGIS?

I am using QGIS + pyQGIS + Python. Layer geometry is line. Each line has a magnitude and a direction (from 1st node to 2nd node). What exactly I want to perform is "graduated width marker symbology ...
2
votes
2answers
205 views

Save multiple selection sets in QGIS

I'm looking for a feature in QGIS but I am not sure if it exists. I don't know the name of such feature, but I call it multiple selection sets. It exists in TransCAD and I find it very useful. It ...
0
votes
2answers
1k views

Using OS Mastermap SLDs in QGIS

In an answer to a question asked by @Canningmister, @tjmgis posted an excellent answer Styling OS Vectormap Local in QGIS? about making OS SLD files work in QGIS. As an amateur user who uses QGIS to ...
0
votes
2answers
444 views

How to derive point height from contour data?

I got vector layer that represents height over sea level. Then, I also have different vector layers. Is there any good way of using QGiS or things related to calculate sea level for those points? ...
2
votes
4answers
1k views

QGIS Polygon precision

Is there a way to edit the precision of polygon points in QGIS so that each coordinate has the same number of decimal places? For example, the coordinate 23.18273917, -84.29172638491 would be ...
2
votes
1answer
1k views

How to zoom to the extent of Qgsvectolayer qgis?

Anyone know how to zoom to the extent of a Vectorlayer in qgis using python plugin?
1
vote
1answer
473 views

Simple Spatial Join of Point Feature to Polygon Target Feature Not So Simple (Source Files Included)

I have what should be a simple task to perform: join ~47K census blocks from the PL redistricting files with pop and racial data joined to Chicago Public Schools High School boundaries to get an ...
1
vote
2answers
222 views

How can I add a pdf as hyperlink for a point in QGIS? Can I do the same in GVSIG?

I am working on a project for which I would have to make a map displaying all archaeological sites of the city; it will later be used and accessed by my office's stuff only. In the end, when clicking ...
1
vote
3answers
2k views

Seeing lat, lot coordinates in raster and getting pixel value

I am new to QGIS and I have a simple question. How can I get the pixel value at a given latitude and longitude coordinate in a satellite raster image? Related to this, I cannot see the latitude and ...
2
votes
3answers
448 views

Problems displaying reprojected WMS in QGIS 2.0.1

I'm loading a WMS layer in QGIS 2.0.1 using the coordinate reference system SWEREF99 TM EPSG:3006, a Swedish crs. The layer displays in the map but when I zoom in to Sweden using the Zoom in-button I ...
4
votes
1answer
329 views

GDALWARP and OGR2OGR / CS2CS not agreeing on transformation

I am trying to transform some data (both raster and vector) from WGS84 to a Croatian Coordinate system defined by: +proj=tmerc +lat_0=0 +lon_0=15 +k=0.9999 +x_0=5500000 +y_0=0 +ellps=bessel ...
0
votes
0answers
36 views

qgis build under ubuntu 12.04, but all the python plugins are not there

All the .so plugin show correctly, only the python plugin do not. I am confused and do not know how to fix this. I think there must be some python problem . The build process is successful.
0
votes
1answer
1k views

How to display coordinates of a point in a projected cooridante system?

I want to check the coordinates of a point. On selecting this point in ArcGIS it displays a latitude and Longitude . In ArcGIS I found an option in 'Identity Tool' that the Latitude and Longitude ...
0
votes
1answer
109 views

WMS orthophotos not visible on screen

Using QGIS on Windows XP based desktop. I have been loading orthophotos from a WMS server up to yesterday morning. Today QGIS correctly connects to the server and apparently loads some bytes, however ...
7
votes
1answer
4k views

Distinction between Difference and Clip tools in QGIS?

What is the primary distinction between the Difference and Clip geoprocessing tools in QGIS?
2
votes
0answers
164 views

How can I improve the resolution of a vector grid made in north pole stereographic projection?

I've been struggling with this for a while and wondered if someone could lend a hand. I have a map which already has sampling points from centroids in a 35x35km grid that was created in north pole ...
2
votes
1answer
1k views

Field Calculator returning incorrect length and area values

I can get accurate lengths of line features and areas of polygon features using the "Measuring Tool" in a QGIS project. However, when I attempt to generate length or area data in Attribute Tables ...
1
vote
0answers
136 views

qgis 1.8.0 crash when starting qthread

I am trying to update a vector layer attribute table using QThread. i connect a pushbutton click with a slot to start the thread: def EGSupdateAttributeTable(self): AttUpdateEGSThread = ...
1
vote
1answer
87 views

Re-sizing Raster file pixels

I have 2 JP2 aerial imagery files that are incorrectly sized. They are 100x larger than the other aerial images but correctly geo-referenced (starting x, y co-ordinates). I believe the issue is their ...
0
votes
1answer
43 views

Apply style to second field

I created a point shapefile in QGIS 2.01. Then, I changed the style of the points so they display the contents of the Acceleration field in the attribute table. Works exactly as I require. Now I ...
1
vote
1answer
282 views

QGIS EasyPrint alternatives for v2.0.1?

I recently upgraded to QGIS v2.0.1 and noticed that the EasyPrint plugin is not supported for the latest version. Will this plugin be updated to work in this version, or are there any alternatives ...
1
vote
0answers
132 views

How to auto-fill a new point vector in a vector layer?

When I work in-situ I manually add points in my shape-file. I would like that when I add a new point some attributes would already filled with values calculated programmatically. E.g in my first ...