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

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4
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5answers
1k views

Is there a Log or Ln function in QGIS Field Calculator?

I can't seem to find any way to take the logarithm (natural or base 10) of a field in QGIS. I have gotten to the field calculator but there is not a button for log and I can't seem find any formula ...
3
votes
3answers
1k views

Georeference to x y coordinates with one lat long origin?

We are running parallel transect lines for a survey, which will roughly cover a rectangular area. When making the transects, we will periodically capture spatial locations of features and events we ...
4
votes
1answer
2k views

How to select and copy a group of polygons in QGIS?

I'm new to QGIS. I opened a few shapefiles that cover Europe. Now I want to select a smaller area and if possible copy the polygons in this area so I can work with a smaller set. How should I do this ...
4
votes
3answers
1k views

How to create a map of only one state in QGIS?

This is a very simple question but a Google search did not provide an answer. Basically suppose you have a map of the U.S. with states and county layers, as well as other layers like roads, etc. ...
6
votes
1answer
1k views

How to create a style file for QGIS from a plain text file?

Using QGIS 1.7. I have a plain text file, which lists 115 rgb values against a map code for a geological map. Viz.: $ head gsv1Msymbology.txt MAPCODE RED GREEN BLUE Oc 143 255 255 WAT 255 255 255 ...
2
votes
3answers
447 views

How to align TIF and GPX layers in QGIS?

My initial layer is an OS tif file, with its associated tfw. I can zoom into the area I want, no problem. The CRS is OS 1936 (and that's the project CRS as well). I download a 'track' layer from an ...
6
votes
2answers
1k views

Is it possible to show Pie charts in QGIS Legends?

I would like to display some pie charts on my map. They show in the map frame perfectly but in legend on the print composer I am unable to show the legend for the pie charts. QGIS just shows the style ...
3
votes
2answers
257 views

Hand fit curve and then apply to time series of rasters, make a map. How?

Maybe a data management problem, not too sure, but likely a challenge which someone has dealt with before. I have a time series of rasters. I can summarise the information by taking averages of each ...
7
votes
2answers
1k views

How to use a field-to-RGB mapping for symbology in QGIS?

Using QGIS version 1.7. I have a plain text file that lists a set of rgb values against a code. I want to use this colour table to colour a polygon layer by mapping one of its attribute fields ...
1
vote
1answer
120 views

Qgis or ArcMap ,find later added data from two layers?

i have two layer which consist of 2010 and 2011 years poi. and in qgis i want to find which poi have been added new in 2011 data .. or can we get result from arcgis or any tool ... thnks
9
votes
3answers
2k views

How to connect QGIS to SDE?

I read your amazing solution in this topic Is it possible to connect to ArcSDE using QuantumGIS?. Unfortunately I'm not so expert in open-source products (we use only Esri suite) and I need to ask you ...
5
votes
3answers
1k views

Developing Web Application For Map [duplicate]

I have huge data of maps usually most of the table are co-ordinates and the other are raster maps stored in SQL server 2008 and PostGres Server. I am using desktop application to analyse the data. ...
2
votes
1answer
267 views

How to modify area polygon in postgres? [duplicate]

Possible Duplicate: Automated correction of parcel geometry based on area measure I need a function to modify area polygon in postgres the major probleme is automated correction of parcel ...
4
votes
0answers
153 views

What open source solution would work best for auto extracting features from satellite images? [duplicate]

Possible Duplicate: Feature Extraction - Land cover I have been looking for an open source solution which would allow me to define a region (or collection of images) and extract features ...
5
votes
2answers
3k views

Where to store (premade) styles?

I have downloaded a set of premade styles (*.qml). Where do I have to store this files for usage?. I am using QGIS 1.7 for windows. thank you! Updates @Underdark, thanks for answering, if found ...
1
vote
1answer
945 views

How to create a PostGIS layer using QGIS API?

I want to create a new PostGIS layer and save changes made to it. Presently, I am connecting Python to PostGIS using psycopg2 but I want to know whether there is any QGIS API function available. ...
2
votes
2answers
1k views

QGIS Server Capabilities Response doesn't contain any Layers

This question is similar as this one QGIS Server not working (problem with fast CGI), but with more details: I installed the latest QGIS from trunk on Linux (Ubuntu 11.04) in the non-default location ...
4
votes
4answers
4k views

Convert ESRI Integer ASCII Grid to something useful

How could I convert a file(s) which is "DIGITAL Map data stored in ESRI ARCInfo Integer ASCII Grid format" into something the rest of us can use? i.e import into QGIS. The main file has no extension ...
4
votes
2answers
887 views

How do I specify a CRS for a fictional game map in QGIS?

I am about to start playing a steampunk RPG game called The Iron Realm, which uses a fictional world map. I have recently started using QGIS v1.7 and have no real experience with GIS sysstems. I have ...
5
votes
1answer
256 views

Seeing QGIS Python Commands

When learning MapBasic I found the most useful way to learn how to do certain tasks was to do them using the GUI and then watch the MapBasic window in MapInfo to see how they were achieved in code. It ...
2
votes
1answer
243 views

Typecast from circularstring to polygon in postgis

How can i type typecast a CircularString Polygon or Multipolygon in PostGIS? I am doing so because CircularString Datatype is not supported by QGIS and i have to create a circle or ellipse, and it ...
3
votes
1answer
234 views

How to Hide Toolbars from QGIS1.7 programmatically?

I am a beginner to QGIS 1.7 and getting problem in hiding the toolbar. I am using: fileTB = self.iface.fileToolBar() fileTB.setVisible(False) This does not work but doesn't give an error ...
1
vote
1answer
133 views

Blank Vector Selection Dropdown in QGIS GRASS Plugin

I realise there are some issues which getting vectors into the GRASS module in QGIS, but is the behaviour i am getting expected? I have loaded the vector shapefile via GRASS, closed G and reopened ...
4
votes
1answer
508 views

QGIS inside buffer with attributes

Fairly similar to ArcGIS: inside buffer with attributes? but in QGIS. It would be convenient if the buffer layer inherited the attributes of the parent. Also I am doing inside buffers (-ve distance ...
2
votes
1answer
4k views

Import MySQL Spatial vector layer in QGIS

I have a spatial table called 'places' in MySQL, with a spatial column 'pt' (point). I tried to import it in QGIS and no points appear. I created a view 'places_as_text' which reproduces the table but ...
0
votes
1answer
102 views

how to overlay GPX data on rasters in QGIS [duplicate]

Possible Duplicate: Overlaying GPX data on rasters in QGIS When both layers are displayed in QGIS, they are not even visible in the same display. The coordinates displayed for each are ...
2
votes
1answer
438 views

How do you change the Window Icons in QGIS 1.7

I am a beginner to Qgis 1.7, and I want to change the icon files in Qgis, (whereever we see the 'Q' icon I have to change that). I tried and I got success in the case of mainWindow, and also somewhere ...
4
votes
1answer
467 views

Is it possible to create color tables for floating point raster maps in GDAL?

I've got a script that dumps a floating point raster that I'd like to automatically color. Currently I load this raster in Arc or QGIS and manually create a color table every time I re-run my model. ...
3
votes
1answer
849 views

Distance between points and polygons in QGIS / PostGIS

I need to work out the distance between a table of polygons and a table of points. The table of polygons has different site boundaries, and the point table has points relating to each of the site ...
0
votes
1answer
1k views

QGIS and MapInfo Projections - EPSG 27700 (British National Grid)

I have some data in a PostGIS table with the projection EPSG 27700. If I export this data from QGIS (v1.8) to MapInfo TAB / MIF when I open the data in MapInfo it has a shift on it. Does anyone know ...
3
votes
1answer
2k views

Add or Import Metadata to a shapefile

Is there a way to add metadata to a shapefile in Qgis? I have the shape file and an xml metadata file and I want to import in shape file.
7
votes
4answers
7k views

How to fix QGIS error “Entry Point could not be located”?

Today, after returning from vacations, I started my QGIS 1.7 and got this terrible message: Help, anyone?
5
votes
2answers
1k views

Quickly create contour polygons from cost points using OSS for web app

This is related to a previous question I've asked: Create filled contour map with GRASS I've created a point layer using OpenStreetMap data and pgRouting's driving_distance() function, where the ...
9
votes
1answer
1k views

How to add features to a PostGIS layer using Quantum GIS?

I am using Quantum GIS and the PostGIS dbms. I am able to call the PostGIS layer into QGIS but i am unable to add feature to it. I am using the method of adding features to a Shapefile but still it is ...
9
votes
3answers
4k views

How to create polygons with straight lines and right angles in QGIS?

I am running QGIS 1.7.0 on Mac OS X 10.6.8. When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles? For ...
3
votes
1answer
105 views

Looking for HowTos or Examples of Presentation Platforms targeting Management/Clients

Any good ideas about using Google Earth to present self contained geospatial data&app to a client or senior management? The broader issue being explored here is that many of our clients are not ...
26
votes
3answers
6k views

How to generate Tiles with QGIS

Is it possible to generate map tiles from QGIS? I guess QGIS Server must have a way to do it, but is there a way to just generate the tiles and save them to disk? With the new symbology renderer and ...
2
votes
2answers
234 views

Is there a way to save manual QGIS changes to Postgis to SQL script?

I am manually editing a Postgis layar with QGIS and would like to export these manual changes in the form of an SQL script. This way: I can do it automatically next time i need to it is easier to ...
6
votes
2answers
1k views

Formatting Dates in QGIS labels

I would like to display a date field as a label. The data is from a shapefile. The field in question is a date field. When I use the date field for the label, it displays in the yyyy/mm/dd format. I ...
2
votes
2answers
240 views

File paths in a PostGIS Table in QGIS

I have a PostGIS table which I have stored the location of some viewpoint photographs. I would like to store the location of the photo file in a field, but when I add a file path in the attribute ...
6
votes
3answers
4k views

Why don't my Shapefiles and OSM data overlap in Quantum GIS?

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine Open Street Map data along with data provided by the City of Vancouver. But the City ...
4
votes
2answers
912 views

How to merge street layers in QGIS for exporting to PostGIS?

Is there any way of merging lots of street data in QGIS and getting one layer for exporting it to Postgresql? I know one method using mmqgis "Merge Layer" tool. It works in Ubuntu but not in ...
0
votes
1answer
1k views

How to solve an installation problem involving QGIS, Python, and a plug-in?

In an attempt to get the plugin "Profile Tool" working, I installed geoslib and python Shapely 1.2.10 module as requested using following: sudo port install geos Then install Shapely once ...
4
votes
2answers
491 views

Invalid Geometry Error after ST_ConvexHull

I've a Postgis table of around 80,000 points and want to be able to populate a second table summarizing the data with convex hulls based on points with a common attribute. For example, the data ...
2
votes
1answer
206 views

QGIS 1.7 + MacOS 10.6 : georeferencing from map canvas bugs

I am experiencing issues with the gdal plugin to georeference a raster. It works fine when I enter the coordinates manually but it does not work when I try to link the plugin with the map canvas. ...
2
votes
1answer
376 views

How to move labels in QGIS using the old labelling method

I would like to use the new labelling method in QGIS, however it does not display labels for all of my polygons. If I use the old labelling method (in the properties dialog) the labels display fine. ...
35
votes
8answers
13k views

QGIS and gvSIG comparison

Many debutant GIS users are asking me which one is better QGIS or gvSIG. Since I use Qgis and I don't have any experience in gvSIG, I aways say that both are very nice softwares and the chose is a ...
6
votes
3answers
1k views

Can Polygons be generalized to MultiPolygons in GeoDjango?

I set up a model with models.PolygonField in geodjango, using postgres as database. I try to import shp into postgres. The problem is, shp (compiled with QGIS) mixes polygon and multipolygon, hence it ...
11
votes
3answers
5k views

How to move vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it? Preferably using QGIS.
28
votes
3answers
7k views

Visualising WKT geometry string in QGIS

A very simple question: Is there a simple tool in QGIS to graphically visualise geometry formatted as text? Example geometry: "POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 ...