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

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5
votes
1answer
303 views

How do “join field” and “target field” work?

New user. This should be simple, but I can't figure out how to perform this basic join in QGIS. (It works in Cartographica.) My shapefile (IL_BNDY_County_Py) has two fields/columns in its attribute ...
0
votes
0answers
52 views

How to extract elevation data from DEM along a polyline [duplicate]

I've been trying to use qGIS to extract and save as an attribute the data elevation along a line, knowing that something similar is available in ArcGIS using the Spatial Analysis tool. So far, ...
2
votes
1answer
460 views

QGIS Routing between two Points without Roads

I'm using QGIS 1.8 and i need to analyze possible routes for roman roads. Is there a Possibility to show routes which comply special criteria, e.g. straightest way between two points, or path which is ...
2
votes
1answer
1k views

How to convert lines from dxf to polygons?

I have several dxf files. Each file, contains the 0 layer. The 0 layer contains lines (which make a closed polygon). In each dxf the lines have their color and line width. I do not have autocad or ...
4
votes
1answer
274 views

How to auto-start a pyQGIS thread?

having build some (two) minor plugins, it's now time for me to link a few (perl-) applications to qgis. As there is no perl-interface in qgis I thought the best way to link both worlds together is a ...
3
votes
2answers
155 views

I am unable to draw a shape layer

When I add a new shape layer or want to edit an existing one, nothing is happening. I even don't see the dots where I'm clicking. Maybe the problem is I deleted some layers (by opening the .qgs as a ...
1
vote
1answer
412 views

How to Georeference a tiff with correct coordinate system

I am having difficulty in georeferencing an existing tiff (already has georeference information - but is out of alignment). Using the georeference plug-in I can create the map's GCP in the 4 corners ...
2
votes
2answers
163 views

QGIS 1.8 on Ubuntu 12.04 doesn't transform CRS properly

I have a weird QGIS-Problem that only occurs in Ubuntu 12.04, but not in Windows 7. I've also tried this on different Ubuntu-Computers. When I try to transform a layer with WGS84 to a different ...
2
votes
2answers
2k views

How can I link java with QGIS?

I want to create a Desktop project on Java which shows radiation dispersion. How can i Link java with QGIS? Is there any tutorial site i can get reference from?
3
votes
1answer
278 views

How to connect waypoint pairs and calculate length?

I want to make a path out of points and calculate the distances of each single line. I have a point layer with waypoints of a research vessel. The way points have in the attribute table a date and a ...
4
votes
2answers
274 views

Connect to PostGIS using SEXTANTE in QGIS

I have a localhost PostGIS database that I would like to use with SEXTANTE in QGIS. I can connect to the database just fine using "Add PostGIS layers...", but when I try "PostGIS execute SQL" in ...
1
vote
1answer
40 views

How to report issues with QGIS documentation?

I stumbled across a gotach while installing mod_fastcgi on MacOs 10.8 (mountain Lion) -- there is a bug in 10.8 in the apache build env which breaks the install instructions here: ...
4
votes
2answers
546 views

Can't select layer to upload to GPS

I'm trying to upload a vector layer to my Garmin GPS unit. I've saved it as GPX (WGS 84); opened the GPS Tools dialogue in QGIS 1.8; selected the "Upload to GPS" tab; and clicked on the "Data layer" ...
0
votes
0answers
539 views

QGIS 1.8.0-Lisboa DBmanager (OSx) can't connect to remote PostGIS 2.0.2 database (Debian)

The PostGIS database is remote but I have made changes to the Postgresql config files and can access it remotely via pgadmin. When I open DBmanager in QGIS I see a note on the bottom that says ...
3
votes
1answer
900 views

Handle add new feature event and/or access feature before commit?

Is it possible with PyQGIS to catch "add new feature" event before commiting changes on the layer? or at least to access new features before commit.
8
votes
2answers
541 views

How to avoid duplicate GIDs when copying features from one PostGIS layer to another?

When I enter new elements (features) in another Postgres layer, I can do it in two ways: Drawing new element(s) (with 'Add feature') which I do rarely or Copying (or cutting) some elements from ...
0
votes
1answer
201 views

Postgresql on Ubuntu Server and QGIS [closed]

Complete newbie... I taught myself the basics of GIS on the job with ArcGIS 9.3. I have been plating with QGIS and have gotten the basics down on both. I am not well versed in the terminology related ...
3
votes
0answers
145 views

Is there a tool for automated quality assurance for vector data captured on raster data?

I wonder whether is any tool(or script) in ArcGIS or QGIS which allows to make an automated quality assurance for vector data captured on raster data? vector data on binary raster:
1
vote
1answer
141 views

“ERROR: invalid input syntax for integer” importing data from Spatialite into PostGIS through DB Manager

I am trying to import data from Spatialite into PostGIS through drag and drop in DB Manager but all I received was an error: Feature write errors: Creation error for features from #1 to #202. ...
3
votes
1answer
205 views

How to display only one representative contour line in legend?

I have a layer of topographic contour lines, graduated by color (using QGIS). My legend wants to display every level and its color. This is not feasible. I need to simply show one representative line, ...
6
votes
2answers
2k views

Why do my Shapefiles not align correctly?

First: I'll summarize what I understand so far so please confirm or correct me. When On-the-Fly is selected a layer is re-projected from that of the layer's CRS to that of the project CRS, IF ...
3
votes
1answer
888 views

How to get the distances (shortest path) between all pairs of points in the river network?

I have 2 vector shapefiles (one line, one point), and I have tried at least 4 ways to try to get the distance matrix at one time (and most concern the directions of each river segment) quantum ...
4
votes
1answer
413 views

How change border line to no pen with python console?

From Python console I load a shapefile with qgis.utils.iface.addVectorLayer. How I can remove border lines (change to no pen) in the active layer?
4
votes
1answer
155 views

QGIS field calculator and Postgres permissions

I’ve given user x the following GRANT ALL ON ALL TABLES IN SCHEMA y TO x; GRANT ALL ON ALL SEQUENCES IN SCHEMA y TO x; GRANT ALL ON ALL FUNCTIONS IN SCHEMA y TO x; However in QGIS they dont have ...
2
votes
1answer
890 views

QGIS opening shp file: why does it crash?

I am trying to open a shp file from the EEA (Urban Atlas), and with some of the shp files qgis keeps crashing as soon as I try to load it. QGIS 1.8.0 is running on Windows 7; I reinstalled QGIS, ...
5
votes
1answer
158 views

What projection is this and how to use it in a GIS?

I have a request to do a map in non-standard projection: (source: http://www4.agr.gc.ca/AAFC-AAC/display-afficher.do?id=1263246127905&lang=eng) I couldn't manage to find it my materials. As well ...
6
votes
1answer
532 views

How to add attributes in proportion to intersecting area from another layer

I am new to using QGIS. I have two polygon layers: Voronoi of Access Points Census block maps with population I want to get number of people covered by each Access Point (Assuming uniform ...
5
votes
1answer
770 views

Pansharpening in QGIS

I was wondering if anyone has successfully been able to perform an image pansharpening within QGIS? I have utilized OpenEV to do this, but the results have been very pixelated. Any info would be ...
2
votes
0answers
52 views

vector cropping failure

I’m trying to crop a vector contour layer using the instructions given at http://lists.osgeo.org/pipermail/qgis-user/2012-February/015294.html . I created a polygon in a newly-created vector layer, ...
6
votes
3answers
2k views

How to create a polygon with specified dimensions?

I'm editing a shapefile in QGIS and want to draw in a rectangle with specified dimensions(Say 101ft by 305ft for example). Is there a way in QGIS to make draw a rectangle with out actually have to ...
1
vote
1answer
152 views

Get feature while editing

I have created my custom form for features editing, using layer.setEditForm("form.ui") and layer.setEditFormInit("init") properties. init method receives dialog, layerId and featId as arguments. ...
0
votes
1answer
155 views

Can you reduce the number of contour lines? [duplicate]

Using QGIS, is it possible to reduce the number of contour lines in a hypsography (topographic) layer? Mine has them every 5 meters, which is more than I need and it makes the map awfully busy.
2
votes
0answers
190 views

oil palm stand census algorithm

Anyone have experience in oil palm stand census using tree detection algorithm from satellite images in ArcGIS or QGIS? any references for usable algorithm? What is the accuracy? thanks for help.
0
votes
1answer
382 views

Using macports python 2.7 with macports qgis

I installed qgis through macports on my mac running OSX 10.8.2 but when I run the application (qgis 1.8) it says that I don't have python-gdal installed. I searched google and it appears that it is ...
0
votes
0answers
57 views

Adding a new attribute to shapefile from Excel sheet [duplicate]

I have a shapefile in QGIS and I needed to add a attribute to the attribute table. The problem is that I have the information I need to add in an Excel file. How can I add the information from the ...
1
vote
0answers
141 views

How can I create a multi layer exportable file (.xcf .psd) from multiple raster image in QGIS?

I have many raster file of the same zone but in differents spectral bands. I would like to create an exportable file of a small portion that can handle different layers. So in practice I would like to ...
3
votes
2answers
561 views

Where is QGIS installation path in Ubuntu

I can't find the QGIS installation path in ubuntu 12.10
2
votes
0answers
224 views

Plot csv data on a map

My boundaries shape file has the following attributes; CODE, PROVINCE, AREA, SHAPE_LENG and SHAPE_AREA (note that there are no geo- coordinates). My data on the csv file has the following fields; ...
2
votes
1answer
169 views

Keep .gdb structure to postgresql + PostGIS (Feature dataset)

I have a .gdb file with a specific structure. I will extract all shp files for uploading to a postgtresql db. But I want to keep the structure of gdb. How can I keep this structure to ...
1
vote
0answers
51 views

how can i plot news stories to show how many stories include each country on a map of the world

We have a table that shows the number of news stories that include particular countries over a set period of time there are three news channels that we have this data for and we would like to show/ ...
5
votes
1answer
2k views

Save Visible WMS layer to file

Is there tool to save currently visible WMS layer to file in QGIS, or some place in QGIS where you can get needed xml to fetch it using gdal ?
2
votes
1answer
196 views

QGIS: Label every other feature

How would I go about labelling every other feature in QGIS (1.8)? For example I have a set of contours every 10meters from 0m to 100m. How would I label only every 20meter contour? e.g. label ...
3
votes
2answers
287 views

Layer not aligning after georeferencing using BC Albers

I'm currently having trouble with the georeferencer... after what appears to be successful georeferencing, the map image layer does not align to the vector data. I'm trying to use BC Albers ...
1
vote
2answers
163 views

QGIS Holux gpx file doesn´t show up

I´ve got a problem with displaying the imported gpx file. The gpx file is created in Holux Funtrek 130 PRo. The map I use is from Openstreetmap, I am sure it is the right map from the location I ...
11
votes
3answers
853 views

Contours: Interrupt contour lines beneath a elevation number

Is there a way to interrupt a contour line beneath a elevation number? Thanks!
1
vote
3answers
313 views

How do I active “Open GRASS tools”-button?

I have opened to GRASS layers and need to use the "Open GRASS tools"-button. This button remains unactivated somehow. Whilst the "Edit GRASS vector layer" right next to it works perfectly fine. What ...
3
votes
2answers
259 views

Merging polygons at county level to state level

I have a shapefile that represents counties (admin 2) only, but I need to create a state level (admin 1) polygon file (I'm using QGIS). I will need to sum up (or average) the relevant data at each ...
1
vote
0answers
135 views

Looking for similar tool (like ArcGIS Diagrammer) in open source for QGIS?

Is there any diagrammer tool available (similar to ArcGIS Diagrammer) for QGIS? thanks in advance : )
0
votes
0answers
119 views

Unable to open old qgis files into the new version ( 1.8.0)

I have downloaded QGIS today for my school work also my Qgis version is 1.8.0 and my school's QGIS version is 1.7.0. So My new Version QGIS cannot run the QGIS file they have send me So Please help ...
1
vote
1answer
321 views

Merge 2 layers based on an attribute column in QGIS [duplicate]

I have a vector shapefile map that is divided into polygons. I want to add 2 columns to the attribute table with the eastings/northings coordinates of each polygon centroid. So far what I've tried ...