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

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168 views

SEXTANTE runalg and QgsVectorLayer issue

I'm trying to make a script for converting polygons to lines. But I'm having some issues while generating temporary layers. In this script, I iterate through all the features of the input layer to ...
3
votes
3answers
523 views

How to find the polygon inside which a point lies?

I have a layer with polygonal features. Each feature has attributes and values. I also have a list of co-ordinates and I would like to know which feature (or polygon) the co-ordinates lie in. Could ...
0
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1answer
61 views

How to Create a Note System inside QGIS

I need to make something similar to a note system, where i can create a feature that will give me something similar to a note system (or a square in the map linked to a feature that will only show ...
1
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1answer
198 views

QGIS Crashes when I try and overwrite a shapefile using QgsVectorFileWriter.writeAsVectorFormat (QGIS 1.8, MacOS 10.7.5) [closed]

I'm somewhat new to this, and working on a plugin. My plugin will create a points memory layer, which is then written out as a shape file using QgsVectorFileWriter.writeAsVectorFormat. self.writer = ...
4
votes
2answers
232 views

How to convert numeric fields into strings with leading zeros?

I'm trying to define an action in Quantum GIS using on of my fields but I have some problems with its format. I have a numeric string like '5' and I need to have a format like '005'. I've tried ...
1
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1answer
100 views

Why new feature disappears when editing polygon?

I try to create internal polygon within existing polygon. After I created a ring, I add a new feature inside the ring. Suddenly, this new feature disappears. I confirmed that this feature went to the ...
1
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1answer
72 views

How do I put label inside polygon at any scale in QGIS 1.8.0

I would like to put labels inside polygon anytime and any scale. I'm using "Labeling" from the toolbar. Although I tried all types of the placement from the advanced tab, some labels still fall ...
1
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2answers
269 views

How to write a QGIS regex for rounding to two places after the decimal point?

In QGIS field-calculator round() is not working in QGIS 1.8 so I try to do the following with a regex: I'd like to keep the first two places after the decimal point - where do I go wrong? ...
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1answer
332 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??
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2answers
74 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
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1answer
404 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
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1answer
131 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
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2answers
106 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 ...
1
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2answers
564 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
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1answer
128 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 ...
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1answer
122 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
142 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 ...
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0answers
260 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 ...
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0answers
706 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
179 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
202 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
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1answer
165 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 ...
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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
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1answer
72 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 ...
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0answers
87 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 ...
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0answers
235 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
96 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
42 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 ...
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0answers
134 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
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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
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2answers
466 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
572 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
103 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
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0answers
101 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
2k 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
851 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
215 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
205 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
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0answers
106 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
70 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
57 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 ...
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1answer
317 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 ...
1
vote
4answers
1k views

How to convert KML (Google Latitude) to SHP on Linux?

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
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1answer
311 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
118 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
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2answers
827 views

Is it possible to colour areas between (vector) contours?

...without making it a DEM first? Joshdoe seems to have done so ("Styled in QGis") here but doesn't say how. Thanks!
0
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0answers
32 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
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1answer
119 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
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1answer
112 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 ...