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

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96 views

how to identify qgsvectorlayer area?

I need to identify the area from Qgis qgsvectorlayer anyone have an idea how to do that in python ?
2
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1answer
48 views

Questions about EPSG:6372

I'm using QGIS 1.8.0 and as CRS EPSG:6372 a projection for Mexico, defined by the Instituto Nacional de Estadística y Geografía (INEGI). I have the following questions, I hope you can help me out. ...
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1answer
43 views

file type needed to add layer containing contour lines

What file format is usable/recognized by qgis to add contour lines to a map? I'm working with Linux Mint 15, and qgis 1.7.5
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0answers
31 views

QGIS rule-based point style responding to number of co-located objects?

I am mapping the geolocated location information for 5.5k Twitter profiles as point data. Many of them have the same location ie "London, UK" meaning that they return identical coordinates. On the map ...
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2answers
187 views

No prj file output from qgis:reproject

I'm trying to reproject a vector layer using the 'qgis:reproject' algorithm in the processing/sextante module of QGIS, from Python. This kind of works, but the .prj and .qpj files created after ...
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0answers
2k views

QGIS 2: How to create a regular vector grid at fine scale and for large area?

In QGIS, we wish to create a regular vector grid with 25*25m resolution and over an area of around 12000 km2. We tried to use: -vector>research tools> vector grid - and v.mkgrid function from GRASS ...
3
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1answer
735 views

Using in-memory vector layer with QGIS processing / SEXTANTE

I'm trying to run the qgis:clip algorithm from console, but am getting an error when using an in-memory layer as the overlay parameter. Is this to be expected, or am I doing something wrong? Code: ...
2
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1answer
146 views

How to change the colormap in QGIS 2.01?

I decided to say goodbye to ArcGIS and switch to QGIS which is nice, but it has given me a hard time to handle various problems. Few months ago, I made a map using QGIS 1.8 with a relief background ...
3
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1answer
171 views

qgis delaunay circumcircles

Is it possible to show the delaunay circumcircles in QGIS? I know how to make the Voronoi polygons and Delaunay triangles. I found a web page that shows the circumcircles at: ...
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1answer
473 views

QGIS 2.0 text delimited layer importing data as single row

I'm trying to import a text delimited layer using lat/lon, but the tool interprets the data as a single line. I've tried saving my csv using several different programs (Stata, python editor, text ...
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1answer
110 views

QGIS Grass Plugin fails with r.cost.vect

I tried the following in QGIS with the Grass Plugin: r.cost input=preCostSurface@albi start_points=OSMroads@albi output=cost0109 max_cost=0 And I get the following error: Dev note: Adapted sites ...
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0answers
141 views

WFS connect SSL handshake fails

I'm running geoserver on my own server at home. Everything works great usually but when I try to connect to WFS from QGIS over https I get a warning saying SSL Handshake Failed. This is probably ...
2
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1answer
90 views

Georeference image is mirrored

I'm working with QGIS and I'm trying to geo-reference a tobin lease map. The map datum: NAD27, projection: UTM Zone 14N. The process to georeference is fairly straight forward but the results I'm ...
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1answer
135 views

Why do area measurements from “measure area” tool and field calculator differ?

My problem is when using the "measure Area" tool on the toolbar I get the correct value but when using the field calculator in the Layer Attributes the area is very different including -ve areas. ...
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3answers
2k views

How to create points based on the distance and bearing from a survey point?

I am plotting witness tree data to calculate pre-settlement tree density. I have a shapefile with points along section lines (square miles) at each half mile. I am making another table that contains ...
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2answers
127 views

geoprocessing across multiple vector layers QGIS2

I have 6 layers of point data (each layer is one year), where data in each layer are distributed throughout a grid, and the grid is identical in each layer. I'd like to extract data from each layer, ...
1
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1answer
297 views

Select by SQL in QGIS Python

In the GUI there is the Query Builder, but that does not seem to be easily available in Python. The processing (SEXTANTE) module has the qgis:selectbyattribute algorithm, but that only supports ...
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0answers
141 views

How to find out Why a QGIS plugin is rejected for Version 2

I have a selection of python plugins (one rather large one) that I have developed under Qgis 1.8 and that I am migrating to qgis 2.0. The error that the Plugin Manager gives me when I load these ...
2
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1answer
138 views

how to use “data defined override” in qgis 2.0?

How can I use the new "data defined override"-funktion in qgis 2.0? I did not find any further information about it in the handbook an somewere else. I want to label my layer with different front ...
2
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1answer
202 views

Raster terrain analysis on QGIS 2.0.1 - No curvature analysis?

I need to perform a curvature analysis on a DEM. I've found this tutorial ...
1
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1answer
226 views

How to calculate the intersect two shapefiles [duplicate]

I have two shapefiles. 1. the clinic buffers 500m area. 2. the postcode area. Is there a simple way to calculate the intersect two shapefiles ? I'm using QGIS Dufour. I tried to use fTools to ...
2
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1answer
107 views

Reprojecting Natural Earth dataset to World Eckert I

My question is connected with QGIS 2. Could anybody explain me how I ought to reproject the Natural Earth dataset there in order my world map to look correctly? When I strive to reproject these data I ...
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1answer
205 views

How to automatically update coordinates in print composer?

I tried "$x" and "$y" for coordinates but it always give me zero "0" values too, and what I really want is to display the coordinates like in this image.
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0answers
61 views

Using QGIS plugins from Python [duplicate]

Is there a simple way to automate calls to QGIS plugins from a QGIS Python script? Either from console or a plugin? I am ideally looking for a way to specify input/output parameters and bypass GUI. ...
1
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1answer
91 views

How to calculate the area of raster catchment zones?

I have a raster with irregular shape and I need to calculate the area. The "classic" method (Vectorize+field calculator) didn't work, it makes thousands of polygons. Any ideas? Thanks a lot!
4
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0answers
151 views

How to select features based upon multiple values in graphical modeler?

I'm trying to create a basic model using QGIS, the QGIS graphical modeler and the sextante toolbar. In part of the model, I need to select features based upon multiple attribute values (for example - ...
2
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1answer
91 views

QGIS layers don't overlay after trying 'enable on the fly' and CRS settings

I know there are already many questions about this topic, but none of the answers helped me so far. I have two layers I want to overlay in QGIS. One of them is an Excell file with the coordinates of ...
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2answers
471 views

How to remove z & m coordinates from shapes with QGIS? (Or arcgis, grass, gdal, Python…)

I've recently received some parcel data in shapefile format that has z & m coordinates (all = 0.0). The WKT for a typical parcel looks like this: "MULTIPOLYGON (((2672464.560700002 ...
2
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2answers
458 views

QGIS 64-bit ODBC set up link to 32-bit Access on win7

I am trying to set up a an ODBC link to Access 2007 32-bit but not having any success. My system is a win7 pro 64-bit and I have QGIS 64-bit installed. Here are the steps I have already tried. Set ...
0
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1answer
243 views

problem in loading outputs from processing tool (sextante) [duplicate]

hopefully some of you have got an answer to what happens to me when i run (so far) all the processing tools for carrying out raster analyses. This is the type of message i receive from QGIS (2.0.1 ...
3
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2answers
969 views

How do I create a shapefile of polygons from points in a spreadsheet?

I have a spreadsheet that has 100 different polygons listed with UTM coordinates for the 4 corners of each polygon. I want to turn the spreadsheet into a shapefile with 100 unique objects, 1 for each ...
0
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1answer
72 views

How to display NoData of a raster in QGIS

How can I show raster pixels with NoData value in QGIS? In ArcMap there is a button to choose the color for the NoData value. Is there something like this in QGIS?
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1answer
126 views

How identify Layer name when removing it from legendInterface qgis?

I am trying to connect the removing layer action with a slot for doing some processing after that. I already try this: QObject.connect(self.iface.legendInterface(), ...
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1answer
78 views

Draw an item from coordinates in QGIS?

Is it possible to draw a line or to draw a triangle or another figure by digit the coordinates of the vertex? I use QGIS 1.8 on windows 7 system.
2
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0answers
209 views

how to make decent sense from scattered river depth measurements

I sampled river depth at scattered positions and I want to be able to make a map and GIS layers out of it. My problems are: As the river meanders the interpolation I do in scientific packages i,e. ...
0
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0answers
124 views

Maxent out of bound error?

I selected my climate data from wordclim ( tile 29 ) and then used QGis to convert the data to .asc format . My occurrence data is in degree decimal.But when I run Maxent on any layer it says that the ...
2
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1answer
157 views

How to multiply raster DEM with a linear graph value

I would like to multiply my Raster DEM with a linear graph value y = mx + C. The graph values look as follows: I want to make a new raster where each cell will represent a damage factor from ...
1
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1answer
60 views

QGIS 2.0 Can I get panels to display as tabs

I recently got myself very confused by getting the "Layers" panel hidden under the "Layer order" panel and then spent hours wondering why I could no longer right click on the layer to get the menu. I ...
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1answer
73 views

Merge two vector layers with different granularity

Beginner at QGIS here. I have two vector layers. One represents country boundaries for the whole world. The other one represents region boundaries, but only for OECD countries. I would like to ...
6
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2answers
244 views

Can QGIS Trace Features?

I generally have an doubt about QGIS. Is it possible to Trace the feature in QGIS? As in the case like ArcGIS for Desktop which has a tool called "Trace" in its Editor Toolbar? If yes, how we can do ...
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2answers
161 views

County-Level Ethnic Shapefile: United States

My professor usually provides the shapefiles that we deal with in our analyses of the United States--population, votes, etc., but I'd like to know how I can get these myself. I'd like, in particular, ...
2
votes
2answers
125 views

How to run QGIS server on EC2 micro?

I'd like to learn something about web maps and so decided to start out using EC2, following different tutorials I was able to start a micro instance but I can't find my way on how to get qgis server ...
2
votes
1answer
328 views

Using a shapefile in QGIS makes it unusable in ArcGIS?

We currently use Arcgis 9.2, and we are looking at moving forward with other software, and we have been testing QGIS recently. Basically we are trying to copy the existing projects we have, and ...
0
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1answer
136 views

Probably base64 encoded WKB - Reading in QGis/ArcGIS?

I have a probably base64 encoded WKB string. How would I load that feature represented by the string into QGis or ArcGIS? I found the QGis QuickWKT plugin, but that does not handle my base64 encoded ...
3
votes
1answer
194 views

QGIS display does not reflect projection

I have slight experience with ArcGIS, but am new to QGIS. I'm trying to set the projection of my map, and I understand that this is done by altering the CRS (coordinate reference system) of each ...
4
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1answer
88 views

Area calculation of an object without coordinates

I have a photo of an object with a scale and I want to calculate its area. I guess I have to create a polygon of the area to be calculated to use the 'field calculator'. But how do I tell the program ...
2
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1answer
232 views

Moving a shapefile point to specific coordinates

In QGIS is there a simple way to move a shapefile point in a shapefile point file to specific coordinates? Without exporting the points to WKT changing the x,y values and then importing the WKT via ...
2
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1answer
768 views

How to call processing toolbox in Qgis' python console

I have been trying to use processing toolbox via python console in Qgis 2.0.1. I am able to write the following comamnds: I am particularly interested to run 'r.statistics' from GRASS module. ...
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1answer
82 views

What is the use of Automatic overview support in Qgis 2.0?

Automatic overview support in map frame is one one of the new feature added in QGIS 2.0. In QGIS 2.0 Documentation explanation about this is given as Automatic overview support in map frame: "Need ...
2
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1answer
549 views

How to resolve “premature end of script headers” error with QGIS Server? [duplicate]

I attempted installing QGIS Server following these instructions. Installation was successful with no errors reported. However, when I try to use GetCapabilities I am getting this error: Internal ...