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

learn more… | top users | synonyms (1)

2
votes
1answer
147 views

How to fix the “The inserted Ring is not contained in a feature”?

I am trying to add a ring in a feature in a shapefile. This feature is a single part feature but has already a few rings. When I try to add the new ring, I have the error message : "The inserted Ring ...
3
votes
2answers
536 views

Can python read the value of a cell in a spreadsheet? [closed]

Can python read the value of a cell in a spreadsheet? The simplest example would be a script that ran a buffer tool on a given shapefile. For the distance parameter, instead of just using a number ...
2
votes
2answers
449 views

shapefiles in QGIS and ArcGis

Hi I'm working with a set of shapefiles and have some problems with the "align" of them in QGis when I load Openlayeres to reference some points. OLs has an straight horizontal baseline but the ...
2
votes
1answer
132 views

Can QGIS be installed on a Server

My question is whether QGIS can be downloaded and installed on a server for multi-user access. Rather than installing the software locally, can QGIS be stored on a server and accessed by many?
3
votes
2answers
400 views

Creating seperate layers out of one big polygon shape by using attributes

I try to explain may problem. I have a big polygon shape (> 200 fields). I have the owners of these fields in a column. I need the seperated shapes for each owner. Is there a tool to do that? Is it ...
1
vote
2answers
146 views

Making Multipart Features to Unique features

I have a layer with two lines crossing over each other. I create intersection point over them and then create a buffer for a specified distance and then using difference tool, I delete the buffer ...
1
vote
1answer
137 views

estimated population around a point qgis

I have a shapefile with points distributed in a polygon. The points are post office locations within a census district. How can I estimate if the post office is a representation of the concentration ...
3
votes
1answer
347 views

Calculate number of people within 50 km of a point

I have two data sets: World population (raster) in EPSG:4326, from http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density-future-estimates/data-download A shp file with points ...
1
vote
1answer
266 views

Where is the default QGIS Point layer style .qml file installed in Win 32?

Where is the default QGIS Point layer style .qml file installed in a Windows 32 bit installation? I have done a search on *.qml and can only find four python plugins styles.
5
votes
3answers
678 views

How to get a list of distinct values from a shapefile field using QGIS?

I have a shapefile whose features I can filter by specifying a where clause in the query dialogue. F.x. I have a field named 'city_name' and by stating 'city_name = "London"' in the where clause only ...
3
votes
1answer
122 views

How to set a default raster style?

Most of my layers in Qgis are shapefiles but I have some raster data which is terrain relief shadings that are GeoTIFFs. In order to save a lot of time with the default colour and density that Qgis ...
6
votes
3answers
1k views

How to create different diameter circles round points?

I want to map a tree survey. I am thinking that I will plot positional points of the trees and then add other data like tree type etc. to the attribute table later. Is there a way I can have an ...
11
votes
3answers
230 views

What is the most appropriate journal for publishing a paper about data collection with QGIS and mobile equipment?

I am a QGIS user, and a few months ago, we used QGIS on a PC Tablet to collect data on nesting birds on a cliff directly on the field. The principle is to have QGIS installed on a PC-Tablet with an ...
1
vote
1answer
82 views

What's the purpose of wms_metadata.xml and admin.sld?

I've installed QGIS Server and it works fine. But in /usr/lib/cgi-bin/ folder I've found 2 additional files - wms_metadata.xml and admin.sld. What is the purpose of these file? I've never used them.
10
votes
2answers
409 views

How to perform repetitive tasks in QGIS?

I am trying to do a treatment on many feature files, so I would like to automate it. In fact, I have one shapefile with the spatial distribution of some species, and one with vegetation type. I ...
2
votes
1answer
150 views

Why are some SVGs not displayed properly in print composer?

I am having weird problem with adding .svg to qgis print composer. I have done some smaller symbols before in inkscape and they work - however the latest one displayed itself as huge black square. I ...
4
votes
1answer
290 views

Is it possible to do spatial interpolation using points in a field?

I would like to use Quantum instead of ArcGIS to make field map but before, I need to know if its possible to do spatial interpolation with definited points in a field (ex. pH points). Is there a ...
1
vote
3answers
472 views

How to create one KML per polygon (from one Shapefile)?

I have a shapefile containing hundreds of polygons. I need to create a kml of each of the polygon. Is there any way that I may not have to deal each polygon individually and my polygon file may give ...
4
votes
1answer
211 views

QGis 1.8 fails to rotate point geometries with rule-based style

I have to do some visualizations in QGIS (1.8.0) and up to now I've been very happy with the new Dialog "Layer Properties -> Style", using the rotation-field to rotate Point-Geometries visualized by a ...
4
votes
1answer
108 views

QGIS printing to file, shading?

Hi I am not even sure how to ask this question and I have googled what i think is wrong with no success. When i create a map with different shadings on it, it looks perfect until it is wrote to pdf. ...
0
votes
1answer
137 views

Joining intersected polylines using rules based rendering [duplicate]

Possible Duplicate: Setting rendering order of line layers in QGIS I have trouble getting two intersecting polylines to look like they were joined at rendering. I am using rules based ...
4
votes
1answer
1k views

What is the best way to connect spatial data with attributes in Excel table?

I have many attributes which are stored in an Excel table. They refer to USA counties. I need to somehow connect those attributes to polygons in some format (don't know which is the best) and ...
2
votes
1answer
230 views

Problems with NAD27 projection in QGIS

I have some data that is in NAD27, but I am having a hard time displaying it in QGIS. I think that the problem is with the CRS. I cannot seem to find the correct NAD27 option. The closest one seems ...
4
votes
1answer
223 views

How can I avoid reprojection gaps when merging DEM rasters?

I have two raster DEMs in same resolution I want to bring together. I was using the merge-function in SAGA, GRASS and QGIS but I always get the following result: What do I need? Where could the ...
4
votes
1answer
757 views

Revealing the different layers of a shape file in QGIS

Shapefile I am referring to is 'NUTS_RG_03M_2010' which is together with several other Shapefiles available in a ZIP file on the Eurostat web site. the ZIP file the available map sets at Eurostat I ...
0
votes
0answers
133 views

How do you normalize a field in Qgis symbology?

I'm trying to normalize a field in symbology in Qgis but there is no normalization option like in Arc. I've tried to add a field to the attribute table and use the field calculator to do the ...
3
votes
2answers
145 views

How to modify two polygons which have common point and line at the one time

I would like to modify two polygon at the one time because these two data has same point and line. Is it possible?? In the present circumstance, I have to modify polygon one by one. First, I ...
1
vote
1answer
133 views

How to remove terracing from Civil3D GeoTIFF export?

I've received a GeoTIFF DEM that was exported from Civil3D and at every contour there is a distinct terrace created when I process an aspect or slope in QGIS with the GRASS plugins. I've looked ...
4
votes
1answer
129 views

Problem with custom projection definition in Qgis

I want to define a custom crs valid for Mexico. The context is that older cartography in Mexico is based on the NAD27 datum. I wanted to test the following proj4 string +proj=longlat +ellps=clrk66 ...
2
votes
0answers
670 views

How to join data from a CSV to a shapefile using QGIS

I'm new to GIS and new to StackedExchange. I need help joining a CSV of Accessibility data to a LSOA shapefile in QGIS. The process explained here does not work for me and I don't know why. The ...
3
votes
3answers
709 views

Auto-calculate field (area or formula)

I'm wondering if anyone has any insight into the potential to auto-calculate the value of a field, either area or distance (ideally) or a formula (based on the values of say 2 other fields, or an ...
2
votes
3answers
7k views

How to convert shape files (.shp) to Cad (.dwg ) format using Quantum Gis 1.7.0?

How to convert shape files to .dwg format using Quantum GIS 1.7.0 ? Thank you
2
votes
1answer
93 views

Can you change the location of .qgis from the home directory to another folder on Windows in QGIS1.8?

Is it possible to change the location of the .qgis folder to another location ( for example on a network drive H:\ ) in Windows?
1
vote
0answers
119 views

How do I fix this QGIS sextante error? NameError: name 'sextante' is not defined

A colleague of mine posted this the other day. We haven't got any nibbles yet and I wanted to elaborate on the issue. We are having trouble running the r.mapcalculator function and receive the error ...
1
vote
1answer
344 views

How to create layer from shapefile in QGIS?

I have a road network shapefile that I want to use to create multiple maps from it, each based on some selection of original shapefile. For example, I want to show all highways with some custom ...
0
votes
1answer
200 views

How can I find and fix broken raster metadata using QGIS?

I have a raster (TIFF) hillshade image that I would like to use in a mapping project. However, I'm having a hard time lining it up properly in QGIS. Through a series of investigations, I have ...
1
vote
1answer
289 views

How to create new columns in QGIS by writng Conditional query on other columns of attributes table

First of all, sorry, I couldn't phrase my question better. So I want to be able to add a new column in my attributes table, say B, and it's value should be 1 if Column A's value is 1 and 0 if Column ...
2
votes
2answers
80 views

How to 'trace' areas from the layer below?

I have some Ordnance Survey vector data for my local area. I want to create a new layer and on it 'trace' some of the areas, fields, verges etc from the layer below with the intention of then ...
0
votes
1answer
266 views

How do I add a Corel Draw map as .dxf file to QGIS and how do I georeference it?

I have a vector data map of Poland, which I exported from Corel Draw. I can display the map in QGIS. At first the boundaries and subdivisions are only displayed as lines, after saving the data as ...
1
vote
1answer
77 views

I have a .sid image but can't figure out the CRS

There is a .map file: OziExplorer Map Data File Version 2.2 Tiritir_2.sid C:\OziExplorer\Maps\Islands\Tiritir_2.sid 1 ,Map Code, Geodetic Datum 1949,WGS 84, 0.0000, 0.0000,WGS 84 Reserved 1 ...
0
votes
0answers
129 views

Qgis ,Area Management of Dealer Network - Analysis of Population versus dealer location and sales performance

I want to analyse a Dealers retail sales performance by location , measuring sales versus population in total and social class etc. I have the shape file for the population of Ireland which includes ...
1
vote
3answers
2k views

QGIS Raster Calculater Syntax

I am trying to use the raster calculator in QGIS to combine a number of rasters. I want to calculate a mean, this is easy: (raster_1@1 + raster_2@1 + raster_3@1) / 3 I then want to create a max. ...
1
vote
1answer
484 views

Create buffer-lines in QGIS alongside Vector lines

I am currently doing a map of a farm, to see which roads needs to be repaired. Those roads are either one sided fenced, on both sides fenced or not fenced at all. I want to make buffer lines around ...
0
votes
1answer
283 views

Error running mapserver export in quantum gis

I have a project in Quantum GIS that I need to export to a .map file using de plugin mapserver export. I fill all the forms but I get this error when running the app. Any ideas of what is ...
1
vote
1answer
240 views

Automatic bulk snapping with FOSS

I'm looking for a tool that would be able to automatically snap features closer than a given distance. Is there such a tool/plugin for QGIS/GRASS/OpenJump? Would it be possible to achieve that with ...
3
votes
3answers
343 views

How do I sort polygons by their latitude?

We have a set of polygons which we would like to sort and number according to their latitude. This will make it easier for local authorities to relate to the numbers of the objects. I have looked ...
2
votes
1answer
450 views

Output of QGIS raster clipper not as expected?

My goal is to clip a raster with a polygon in QGIS 1.8. Based on an article I read, this should be a pretty straightforward task. However, the output appears to be empty. The raster produced is the ...
1
vote
1answer
638 views

How to draw grid cells in QGIS?

I have one ASCII text file with eight columns. The first four provide the x-coordinates (e.g. longitude) of the four corners of a grid cell, while the last four provide the y-coordinates (e.g. ...
6
votes
2answers
630 views

How Can I Make QGIS Stop Blinking Every Time I Pan?

The way QGIS draws the canvas when panning is quite annoying. If I pan the map even a little bit everything goes blank for a second or two before the layers are drawn. It looks like this happens only ...
3
votes
1answer
81 views

Get rid of raster grid cells that are less than 1

I'm using QGIS to work with raster data. I have a raster dataset of a country where each grid cell is assigned a number 1-100. However, the raster is in the format of a rectangle based on the extent ...