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

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2
votes
2answers
120 views

Sextante modeler feature selection

I am trying to select grids (polygon geometry) that intersect with a building layer. I can do it by using "Select by location" tool and then I generate centroids from the selected grids. There is no ...
1
vote
1answer
351 views

How to add layer/raster with specific position in the QGIS layer list?

I use addRasterLayer(rast,'Name') but this adds the raster to the top. It is possible to set position when I add raster at once? Is it possible??
1
vote
2answers
77 views

Error reported when trying to import prj for data points in New Brunswick Canada into QGIS

I have data points recorded with a Trimble GIS. The projection is New Brunswick Sterographic Double Projection, which as near as I can find via a Google search is EPSG:2953. However, when I try to ...
1
vote
1answer
502 views

Rasterize vector layers with different extents into identical raster grids with QGIS

I am working on a quite simple spatial potential analysis using QGIS. I have some ArcGIS knowledge, but I am new to QGIS. My task is to identify the functional inner city of a region based on ...
0
votes
1answer
133 views

Grass algorithms doesn't appear in the sextante toolbar in QGIS

I was having problems with some sextante algorithms in my QGIS 1.8, something related with wrong "os" name, I found a post in which reccomend to install the 1.9 master version. I clean uninstalled ...
2
votes
2answers
107 views

Are there any known issus opening a QGIS Desktop project on Android?

Does anyone else have trouble when they try to open a project which was worked on in the QGIS desktop version 1.8 (I understand this is the most up to date version for the desktop) and try and open it ...
2
votes
2answers
739 views

QGIS, point clouds and photogrammetry

I'm trying to use photogrammetry and Structure from Motion to record buildings, and I'm looking for a way to bring these into a format usable in GIS, in particular pointclouds and models of terrain, ...
0
votes
1answer
134 views

How to setup and use GRASS?

Previously I've asked an question and Micha gave me a helpful advice:How to find the watershed area for each point in the river network using DEM? After getting the useful DEM file, I began to setup ...
-2
votes
1answer
141 views

Qgis: Select multiple layers in sql-Filter [closed]

I have a Shape-File with lines of streets. Now I want qgis only to show the categories: Type: primary and Type: secondary and Type: motorway. How do I do this? This doesn't work: "type" = 'primary' ...
1
vote
1answer
158 views

how to rename the band-names of a layer stack?

I created a layer stack of 20 images (all GTiff-files) using the gdal_merge tool in QGIS, available at: raster > miscellaneous > merge The result is a GTiff layer stack of the 20 images, but ...
0
votes
0answers
290 views

Create a polygon shapefile using point as boundary

Following have two problems: I am now have 4 point in a shapefile and I want to set the point's coordinate for boundary of a polygon The points are xmin, xmax, ymin, ymax that can just be a ...
0
votes
0answers
901 views

Vector Intersect QGIS (1.8.0) Gives empty shapefile

I am trying to find points that fall within a polygon. Both layers are vector ESRI shapefiles. I used the fTools based intersect under Vector>GeoprocessingTools>Intersect. The output is an empty ...
2
votes
1answer
189 views

How to store attributes of a large shapefile in a list?

I am trying to store the attributes of a shapefile into a list. With following code it works for smaller shapes: addA = [] While provider.nextFeature(feat): attrs = feat.attributeMap() for ...
2
votes
0answers
212 views

Divide polygon layer by point layer in QGIS?

I have two layers - one polygon layer that is a buffer of a road layer, and one point layer that shows certain locations along that road. What I want to do is to divide/split the polygon layer at the ...
1
vote
1answer
186 views

getting a merged color satellite image from red,green, blue, pan, and nir tifs

I am using Tiff images from Digital Globe and trying to get a color satellite image. I have merged the red, green, blue, pan and nir tiff files into one file. I then changed the band properties to a ...
0
votes
0answers
84 views

Sextante script for statistic info

I want to generate a script for getting statistic information window from selected feature. For example i have two layer building(polygon) and railway(linestring). By using this tools i got a window ...
0
votes
1answer
74 views

Help needed with the use of FARSITE

Is there anyone who has worked with FARSITE? I can build some of the files needed, such as slope and aspect, but not sure where to start when it comes to building files for 'canopy', 'fuels', etc. I ...
1
vote
0answers
91 views

GIS Maximum area coverage problem

I want to find optimum antenna location for an area. Every antenna can cover an circular area. These areas diameter is 750meter. So how can i find minimum number of antennas and locations. NOTE: I use ...
1
vote
0answers
302 views

How to write vector layer to csv file with geometry by PYTHON?

I use Python try to write vector layer file to csv file with this code QgsVectorFileWriter.writeAsVectorFormat(mylayer, r'c:\temp\xyz.csv', "utf-8", None, "CSV") It can export to xyz.csv but only ...
1
vote
1answer
104 views

How to rescale vector data? [duplicate]

I've got some old maps in dxf format. QGIS imports them correctly but with a nonsense scale. It can export the data it gets to shp of course. Does anyone know how to rescale vector data so it can be ...
0
votes
1answer
43 views

QGIS Symbology changes by number value

I've gotten a state file with count outlines joined to an attribute file that shows numbers of items per county. ArcGIS has the ability to set the symbology to grade the results into pre-determined ...
0
votes
0answers
148 views

Why do my Attribute table joins result in all NULL?

I spent hours getting "null" results in joining a downloaded state and county shp file to a self-created file (SCF). What I found was that the SCF had to have "EXACTLY" the same set of names/ID#'s as ...
1
vote
1answer
1k views

How to transform World data from EPSG 4326 to EPSG 3857

I have tryed different opensource tools to transform a world data shapefile from 4326 to 3857 but I always have an error. Im not sure, but is it because of Antartica? I have tryed with GDAL and QGIS ...
1
vote
2answers
561 views

Trigger to fill attributes (data, client ip) in table for each new objects, PostGIS

In PostgreSQL/PostGIS database stores shapefiles. Client users software - QGIS. Please help me write PostgreSQL/PostGIS trigger, which for each newly added/updated feature in layer added 'time create' ...
4
votes
1answer
661 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
107 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
229 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
87 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
162 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
378 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
370 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
132 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
518 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
525 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
142 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
298 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
520 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 ...