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

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4
votes
1answer
658 views

How to set up Python 2.7 to work in both QGIS and ArcGIS?

I have both ArcGIS 10.1 and QGIS 1.8 installed and both include Python 2.7 in slightly different setups and in different folders (c:\Python27\ArcGIS10.1\ and c:\Program Files (x86)\Quantum GIS ...
4
votes
2answers
108 views

“GIS” Mapping on Monument - Scaling

I have a Baroque tombstone for which I have to map the damage phenoma. Normally one can use a vector drawing programm but one has always two boundaries between the different polygons. Questions: Is it ...
1
vote
0answers
106 views

Problem using grid with a vector layer

I need to establish a model of maritime pollution and I try to use the grid option to work on ocean sectors. I tried to use my grid on a vector file, .shp, with points. Each point is a maritime ...
5
votes
1answer
3k views

How to select points within a polygon from another layer?

I'm using QGIS 1.8 with a PostGIS database and I have three postgis-layer in qgis a lines layer, a points layer and a polygon layer. What I'm trying to do is to select a polygon in the polygon layer ...
2
votes
3answers
1k views

How to convert a txt file to shp?

I've got a txt/csv file with the utm coordinates and the hights. Now I want to upload this into qgis. This is not a problem so far. The problem is to create a shapefile out of the data with an ...
1
vote
1answer
229 views

Pseudo Mercator error?

I'm mapping on QGIS, I have a vector layer and his CRS is on EPSG:4326 - WGS 84, but also I wanted to put a satellite image, so when I do it, the image use WGS 84 / Pseudo Mercator. The problem is, ...
1
vote
1answer
227 views

How does QGIS calculate the area of a polygon?

I am working on a project that requires the calculation of the area of a polygon by two different methods. I need to know what algorithm QGIS uses to calculate the area of a polygon. I know ESRI ...
0
votes
0answers
116 views

Use QuantumGIS to bulk-import csv files

I have a large set of .csv-files containing geographic information. Every dataset consists out of 2 .csv-files! This is my folder-structure. All files in Tracks are formatted equally and all in Routes ...
2
votes
1answer
86 views

Can I use the globe plugin on a Windows OS and where can I find the plugin for QGIS?

I am trying to add my layers (health facilities and pertinent infrastructure within a region) to a 3D image of the landscape and someone recommended I use the Globe plugin. I can not find the Globe ...
3
votes
1answer
59 views

what is the minimum to install of QGIS for it to work?

This may sound like a daft question, but I'm looking to understand what the minimum parts of the install procedure I need to install to get QGIS to work (i.e. can it be installed without GRASS etc?) ...
2
votes
1answer
161 views

Why are towgs84 definitions missing on Ubuntu 12.04 compared to Windows?

Why for some of my most used CRS the 'towgs84' part of the definition of the layer spatial reference system is missing, compared to the QGIS for Windows? EPSG 3004, 23032, 23033 when used with QGIS ...
-1
votes
1answer
375 views

CSV with latitude and longitude to a spatial points with QGIS 1.8

i have a csv file with latitude and longitude of several addresses and a shape file of a region. I want to plot this points of the CSV file into the shape file. But I don't know how to transform these ...
2
votes
4answers
1k views

How to convert KML with tracks to Shapefiles?

I downloaded a KML track from Google Latitude. The service allows to download the tracked route from the user's profile providing a link such as: ...
1
vote
1answer
367 views

How to export a .sid image as high DPI .tiff or .bmp from QGIS?

I have 2 50 cm resolution areal photographs in .sid format. How can I export these layers as a regular image format (like tiff or bmp) which I can then open in any simple picture viewer program? I've ...
4
votes
1answer
132 views

Can QGIS perform graphic clipping?

In ArcGIS for Desktop there is an option to graphic clip inside the data frame - this clips the feature you're viewing without actually clipping the feature into a new feature. Does Quantum GIS have ...
3
votes
2answers
1k views

Colouring areas between (vector) contours?

Is it possible to colour areas between (vector) contours without making it a DEM first? Joshdoe seems to have done so in Create filled contour map with GRASS but does not say how.
0
votes
0answers
34 views

Change text format and visibility

I need better visible names of towns, because at the big scale is bad reading --> i want to setting visibility and format. For example name "Ústí nad Labem" is good visible but another big city in my ...
1
vote
1answer
136 views

How to symbolize more than one attribute simultaneously in QGIS?

Each symbol can show different properties such as temperature and pressure, etc. I want to change the symbol color according to one property and size with another one. How can I do it in QGIS? Thanks! ...
0
votes
1answer
131 views

Problem executing Mean Shift Segmentation

I have a problem executing the Mean Shift Segmentation in QGIS with Orfeo Toolbox. I put all the parameter to execute and then, nearly 5s after appear the message that SEXTANTE could not open the ...
1
vote
2answers
514 views

How to calculate Image boundary / footprint of satellite images using open source tools?

I'm referring to this question&discussion: How do I create a shapefile showing footprints of Rasters? I need to create the polygon outlines of several single layer raster images, not the ...
1
vote
1answer
523 views

How do you scan/quantify vegetation using satellite images?

I am relatively new to GIS (about 4-5 months in) I did not receive any formal education about this so I am completely clueless about how to go about measuring/quantifying vegetation using satellite ...
1
vote
4answers
3k views

Get pixel value from a raster in a xy table

I'm trying to find a way to convert a raster (in my case it's a Landsat satellite image) into a table with 3 columns which would represent: 1) x coordinates (the so called "xllcorners" in ASCII ...
2
votes
1answer
140 views

Can QGIS get the GPS Coordinates via the 'Windows Location Provider'?

Can Quantum GIS get the GPS Coordinates via the 'Windows Location Provider' in Windows 7/8 instead of reading a virtual com port? If not, could this be developed as a Windows-specific plugin? (Is ...
4
votes
3answers
290 views

How to create scattered points in polygon

I have few polygons and I want to create few scattered well distributed point within the polygon. I am used to with ArcGIS and QGIS platform. How can I make it?
2
votes
2answers
515 views

How do I import UK Environment Agency Lidar data (.asc) into Quantum GIS

I have downloaded Lidar data from the UK Environment Agency as ESRI ASCII files but being a complete novice as far as GIS is concerned I do not know how to view them. Quantum GIS was recommended to me ...
3
votes
3answers
1k views

Obtain all elevations points from a raster DEM

I need to obtain all elevation grid points from a raster DEM. I see the steps required as: Read in raster DEM (Arc Info Binary Grid format). Create subset area using Points2One (see triangle area ...
2
votes
1answer
325 views

Combining polygon geometries with python and QGIS segfaults

I am trying to combine polygons, using Qgis 1.8, and every time I run this script in the python console, I get a segmentation fault. Here is the script: from PyQt4.QtCore import * iface = ...
0
votes
0answers
36 views

How to change value of an Line edit dynamically

I create a form in QT4 and compile with pyuic4. it create an form.py I want to modify the value of the line edit dynamiclly with code. I put this code in the form.py but never happen: ...
0
votes
1answer
90 views

Make many lines in one layer (Python)

I what to create many lines with this code: v_layer = QgsVectorLayer("LineString", "cable", "memory") pr = v_layer.dataProvider() seg = QgsFeature() ...
0
votes
2answers
922 views

How to Join Attributes by Location in QGIS 1.8.0

I have a points layer with site attributes and a polygon layer with region attributes. I'd like to join the names of the regions to the point site locations using QGIS 1.8.0., on Windows XP. ...
0
votes
2answers
83 views

Python to get ids from shp dont return all records

I have some Python code to get the ids and georeference from a shapefile: canvas = qgis.utils.iface.mapCanvas() allLayers = canvas.layers() nos = QgsFeature() for i in allLayers: if ...
8
votes
1answer
271 views

How to automatically reduce polygon size?

I am working with two polygon layers (counties & states) which I will 'intersect' to find which counties are within which states. Due to data inaccuracies I have to change all county polygons and ...
0
votes
1answer
99 views

How to convert geometry of SHP to decimals

I try to create a line with two points. These points are obtained in a SHP layer. How can i convert that points to decimals? Thank you
2
votes
1answer
166 views

How to clip roads to exclude those within a flood zone?

I have OSM road network data in QGIS along with a shapefile showing the possible extent of a flood. My question is: is it possible to exclude all of the roads that are in the flood zone (so as to ...
5
votes
2answers
639 views

Calculating distance and/or time taken to travel from population centre to nearest hospital in QGIS

I'm trying to find out how long it would take to travel by car from each of the Lower Layer Super Output Areas (LSOA) in Norfolk, England to the nearest Hospital (or just what the distance is and I ...
0
votes
2answers
476 views

How to display data from a feature?

I want to display data based on the feature currently selected/clicked on. I am following a tutorial from http://www.qgisworkshop.org/html/workshop/plugins_tutorial.html. It initially shows you how ...
0
votes
1answer
265 views

How to use expression in QgsVectorlayer label by using python?

how to show the two field values as a label on features. I have done it for a field called "ErrorDescr" with this i need to show another field values. Other field is "MarkerId" ...
0
votes
1answer
83 views

trace a transmission line for a certain distance

I’m looking for a way to easily trace a transmission line for a certain distance. Here is the scenario that I am working with. We have an issue with our transmission line; our OMS tells us that there ...
-1
votes
1answer
127 views

How to change windows can't find D:\Program [closed]

Today, I setup QGIS. When I run msys, it appear 'windows can't find D:\Program'. Why? Thank you!
1
vote
1answer
67 views

looking for datum to georeference maps of 19th century Maine

I am trying to georeference 3 (1840, 1844, and 1877) northern Maine maps. I really am not able to find which datum to use. Can anyone point me to a list of historic and regional datums? thanks
1
vote
2answers
257 views

Easy Custom Labeling plugin does allow to save?

I use the Easy Custom Labeling plugin chose positions of the labels and safe the layer and project for continuing later. When opening again the project, the layer opens but without any objects inside. ...
4
votes
1answer
110 views

How to select behind feature which is overlapped with the same layer on QGIS 1.8.0

My issue: I received data which was created without "Avoid intersection of new polygon". There a few overlapped feature with the same layer. I could fine overlapped feature by the spatial query. But ...
1
vote
1answer
1k views

How to find the watershed area for each point in the river network using DEM?

Update#1: Thanks, Micha, I have followed your instruction and successfully use the modules in GRASS. I use r.watershed to get the basin raster and the drainage line: and I use r.water.outlet to get ...
1
vote
1answer
942 views

How to get correct format of coordinates for export to geojson from QGIS?

I've created a custom map in QGIS with a few shapefiles. I'm using leaflet.js to render the map and the shapefile points and everything lines up correctly. The CRS is set to 4326. When I export the ...
4
votes
0answers
1k views

Loading raster from PostGIS DB into QGIS: succeeded yesterday, fails now [closed]

I have a PostgreSQL(v.9.2)/Postgis(v.2.0.3) database which includes raster layers (added through raster2pgsql). To open them in QGIS (v.1.8.0-Lisboa), the "Add Postgis layer" menu will not work; ...
1
vote
2answers
219 views

How to select two points on a map using QGIS?

I need to select two points on a map in QGIS. I selected the element selection tool in menu view and I want to select two points. How can I accomplish this? Are there other tools or methods to ...
0
votes
1answer
172 views

QGIS Python - Convert geometry from Postgres to QgsPoint()

I have made a query in Postgres to get some points to use with python. This points are in geometry data. How can I convert that geometry in decimals to use QgsPoint() in python? Thank you
0
votes
0answers
101 views

Adding a WMS - connection timed out?

I am trying to add a WMS service to qgis but am having some problems. After adding the url and name of the service and clicking on connect, I am receiving the following error message:- "Could not ...
0
votes
1answer
394 views

Nearest neighbor analysis not showing results

I'm trying to do a nearest neighbour analysis on fish shoals distribution. I go to Vector > Analysis Tools > Nearest neighbour analysis. I choose the appropriate layer and when I hit ok the black ...
0
votes
1answer
56 views

How to find the overlap of three polygons?

I have three polygon areas showing different land types and I want to create a new layer based on where the three layers overlap each other. I thought this was a subtraction query but havent been able ...