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

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250 views

How to Project a point on feature in PyQgis?

In Arcgis IProximityOperator.QueryNearestPoint Method was available to get the nearest point. Similarly Is there any function available in pyQgis? Thanks in Advance.
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1answer
228 views

Join Tables related by a composite primary key in qgis

I have two tables, one has the geometry and other has attributes. The table with geometry has unique number primary key, and 4 columns admin1,admin2,admin3,featureid. Table two is a csv file has the ...
2
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0answers
93 views

Is there a way to build topology and work with topology relations in PyQGIS?

Is there a way to build topology and work with topology relations in PyQGIS? I'm asking because I need to run some custom generalization algorithms on my data, and I need to preserve topology. ...
2
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1answer
431 views

How to mosaic Landsat 7 images correctly?

This is a result of mosaicing of two Landsat 7 images (layer stacked) in TIFF format. I was aming to put these images together with no overlaping visible line between them. The process was: Added ...
3
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1answer
288 views

How do I set the composer layout units to inches?

I open an new composer and select ANSI A for my paper. The notation after the name is "Letter; 8.5inx11in", but the width and height are displayed in mm, and the units selection is grayed out, so I ...
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1answer
56 views

Can I offset the map frame in the composer?

I have a map frame in a layout in which the map fills the frame. If I check the frame property checkbox, there is no whitespace between the contents and the frame. Is there a way to offset the frame? ...
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2answers
349 views

How to change the aspect ratio of a map without the scale changing? [duplicate]

The aspect ratio of the map frame doesn't match the contents, leaving a lot of white space inside the frame, even after I've scaled the contents to fill one dimension. When I drag one edge of the ...
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2answers
75 views

Is it possible to customize the Vector and Raster menus?

a little but nervous problem. As you know QGIS offers the possibility of strongly customize all the menu, toolbar, statusbar,... thanks to the option Customization in the Settings menu. Here the ...
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1answer
184 views

Is it possible to label bar charts?

I have added bar charts to my map and this works fine. But I have no idea how to add values to the bar chart. For example one bar shows the value of 2000 and another shows the value of 2100. Is it ...
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1answer
119 views

problem display tile when config tilecache for WMS

i have a problem with config tilecache for WMS when i have shown it. but there are proplem when display tiles. any idea? this is my config for tilecache.cfg [world] ...
5
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2answers
19k views

How to make work tablet integrated GNSS (GPS) on Windows 8 with QGIS?

I have tablet - Dell latitude 10, running Windows 8, with integrated Broadcom GNSS Receiver BCM47511 (GPS,Glonass...). Because it is integrated GPS and Windows 8, there is the "new" way of providing ...
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1answer
177 views

How to use QGIS Atlas with multiple layers/files per coverage?

I've got 30 contour datasets that all sit over the same extent. Each contour set is in its own file. I also have 30 extent polygons for each contour set as a separate file. Can I use Atlas to ...
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1answer
5k views

How to clip a line layer based on polygons with QGIS?

I have a line layer and a polygon layer. Both files have the same SRS. I want in a new shape file only the lines covered by the polygons. I tried in QGIS the Vector -> Geoprocessing -> Clip ...
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0answers
565 views

How to convert lines to start points and end points?

I know there are several ways to convert lines to points in Qgis but I have not been able to find a solution that will convert the file so that it indicates if the point is the start point (upstream) ...
2
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2answers
1k views

Read gpx track points in QGIS

I want to read GPX track points with their time stamps into QGIS. I try GPS Tools, GPX Conversions, Waypoints from a track. This fails on my PC at office (QGIS code revision d94c044). Sometimes QGIS ...
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1answer
242 views

Set QGIS vector layer custom properties

I'm trying to set some labels and styles for some vector layers that are loaded programatically from a Spatialite database. I have the following code, which returns no error, and includes the changes ...
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1answer
233 views

How can I always run an algorithm with standard input shapefiles from mapcanvas in QGIS 2.0.1?

I created a model in the graphical modeler and I want to run that model always with two specific polygon shapefiles from my project, e.g. pst and astenot. Whenever I run my model, it asks me to set ...
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1answer
382 views

Field Calculator - replace string function - data value recognised as a column and is “not found” [closed]

I have the same challenge as GrahamD - Field Calculator - replace string function I have exactly the same challenge. Exactly the same as GrahamD's challenge, p abbreviated for pan. Type_2 as a test ...
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0answers
183 views

Why does the SAGA raster calculator fail when used in a Processing model?

I have a problem with the modeler and the saga raster calculator. When I'm using the raster caculator without the modeler it works fine. When I'm using the saga raster calculator in my model I always ...
2
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1answer
437 views

Qgis OSM and layer projection problem

I am using QGIS 2.1.0, and trying to import my vector layer(parcels) with OpenStreetMap layer. My vector layer (parcels) use EPSG 31277 coordinate system. This is the definition for EPSG 31277: ...
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0answers
553 views

Google Maps Engine Connector error

I have recently installed the Google Maps Engine Plugin for QGIS 2.0 and it doesn't seem to work. Whenever I click on the Log in button it pops up with: Google Error:invalid_client Bad request. ...
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3answers
381 views

Table Relate Spatial and Tabular data in QGIS 2.0

I am self taught in GIS, so I apologize ahead of time for my noobness. In ArcGIS you have two options to associate data in a table to spatial data. Based upon my understanding, the first is Join ...
2
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1answer
106 views

How do I create smaller maps for publishing from multiple tiles representing a large map using QGIS?

I am completely new to cartography and QGIS - I'm a writer, editor and acceptable designer (Adobe Creative Suite). I wish to produce PDF tour guides featuring maps that display a route. One version ...
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2answers
1k views

How to use the replace string function in Field Calculator?

Within an attribute table I'm trying to replace one string with another using the 'replace' function . As an example, there are a number of features whose field 'NAME' contain the string '(B)' and ...
2
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1answer
119 views

Loading / georeferencing OS rasters in QGIS

I have got some OS rasters but there isn't georeferencing file (TFW) with them. When I try to load them, it will obviously load in the wrong place. They are loading fine in a different GIS software ...
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1answer
123 views

What is the 'water retention capacity' tool and how is it used?

In the latest version of QGIS, I found a geoalgorithim in the processing toolbox that will generate 'water retention capacity.' I am familiar with DEM-based hydrologic modeling tools in QGIS, but I ...
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1answer
172 views

QGIS how to compute a trendline of two point lines? [closed]

Does anyone know how to compute a trendline for two lines of points? I have two lines of points of a 10 km long urban road. 1st line is one driving direction and the 2nd line of points ist the other ...
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3answers
480 views

How to access user credentials in database connection?

I am trying to automate a couple of things when a QGIS plugin is activated: If Layer A is not in the TOC, add it. This requests username and password to access a PostGIS table using the inbuilt ...
3
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3answers
864 views

How to draw (or add) a line indicating a specific latitude/longitude?

I'm trying to add a single line that show a specific latitude (e.g. the Tropic of Cancer) I don't want a gird but only a single line even in a vector layer.How can I do that I've try with pyQGIS ...
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0answers
240 views

Editing of vector layer programmatically with QGIS

I'm trying to edit vector layer using Python console and have couple of questions. Why this approach doesn't work and I have to use canvas.refresh? If I will use this code not in python console but in ...
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0answers
56 views

Problem with GRASS in QGIS

I am trying to import a vectorlayer to GRASS from QGIS. I get an error and hope someone here can help. Been trying to fix it for hours, but come no closer to a solution..... This is the error I get: ...
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1answer
178 views

How to fix QGIS crashes when using GRASS toolbox?

I've installed QGIS 2.0.1 on Ubuntu 12.04. exactly as explained on qgis.org . Unfortunately QGIS crashes when trying to use any GRASS model (r.aspect as example): just opening QGIS, click on toolbox ...
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2answers
1k views

keep the same field headers after joining a table to a shape file in QGIS

I noticed that after joining a table to a shape file the headers of each fields in the table used for the join are changed by QGIS and they are attributed to a different name. For instance, i had a ...
4
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2answers
110 views

How to replicate trunc function on QGIS?

I've search a bit before asking this question, but I haven't found the answer. Is there a Trunc function on QGis? I've tried using floor, but it doesn't work (like I want) if the number is negative, ...
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1answer
235 views

Is there a way to automatically calculate attribute values for new features?

I am creating a vector point layer which will be added to over time. I have been using the field calculator to populate fields such as X and Y coordinates. I'm wondering if there is a way to have ...
2
votes
1answer
1k views

How to pick the coefficient in Inverse Distance Weighted method?

I'm using QGIS 1.8.0 to interpolate weather data. This is, I have a weather station located in say, A and C. With the Inverted Distance Weighting or Triangular Interpolation methods, I can ...
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0answers
700 views

Trying to make QT + QGIS working

I'm mostly a Java programmer, I worked on C++ many years ago, and knowing this my project manager has asked me to create a little app in Qt that can open a shape file, using QGIS. But I'm encountering ...
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1answer
572 views

QGIS, making a topo map from an excel file

I will appreciate your help. I am new to QGIS, this question might be common but trough me search I did not find the answer I needed hence my question here. How do I make a topo map ( raster) from ...
3
votes
2answers
1k views

QGIS 2.0.1. missing Google Mercator CRS

I've downloaded the latest QGIS version and I cannot add basemap. I installed OpenLayers plugin and while adding any map from list QGIS crashes. I tried to enable Google Mercator CRS first, yet it's ...
0
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1answer
23 views

QGIS 1.8 or 2.01 select entries in .shp file that match a field entry [duplicate]

I've got a .shp file with 40k points (trees) in it. One field is the species name. Is there a way to select those entries that match a desired field name e.g. 'black walnut' so I can move them to a ...
3
votes
1answer
157 views

How to get projected centroids in QGIS?

I am trying to get a centroid for several polygons on a global scale, in a way that it would correctly represent the common centre of all the polygons, taking Earth's curvature into account. The ...
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0answers
166 views

How to install GRASS in QGIS Dufour?

How do I install GRASS to run in QGIS 2.0.1? GRASS is not listed in the Plugin Manager and attempting to access it via the Processing Toolbox gives me the following error:
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0answers
82 views

How do I shorten the refresh rate of qgis_mapserv.fcgi?

Is there a way to shorten the refresh rate of qgis_mapserv.fcgi? After having uploaded a revision of a file these changes do not take effect in qgis-web-client. I guess it's because the computed tiles ...
2
votes
1answer
39 views

Get coodinates from point shapefile

I converted a line shapefile to points as you can see in the attached image. Is there a way to know the coordinates of each point? Any help would be really appreciated! PD Im using QGIS 1.8.0
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0answers
148 views

Merging contour lines along tile boundaries

I am working with the CANVEC data set. The data in canvec is broken up in to mapsheets. eg. 116B04. I have data covering the entire province of the Yukon. I have merged all the data in to one ...
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1answer
127 views

How does QGIS Topology Checker check the topology of SHP and OSM files? [closed]

Can anybody make me clear if .shp & .osm (OpenStreetMap Data) are holding topological data/relations or not. if .shp files are not holding then how qgis plugin topology checker checks for the ...
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1answer
162 views

Is it possible to connect to FEMA's WMS and WFS using QGIS?

I have just found out about the wonderful world of WMS and WFS. I have added the FEMA versions of both to QGIS. WMS and WFS. The WMS seems to connect and adds something to QGIS, yet it is not visible. ...
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0answers
420 views

How to share ArcMap shapefiles with QGIS?

I'm trying to send a ArcMap 10 shapefile for a QGIS user and something happens with attribute table during the process. Columns will be rearranged, hidden digits will appear to coordinate columns and ...
6
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1answer
340 views

Can I create a reusable text annotation style in QGIS?

I want to create a fairly simple map with a few locations emphasized using annotations. I don't like the default annotation formatting: So, I've reformatted the annotation background color, ...
5
votes
2answers
749 views

Ortho Projection produces artifacts

I`m trying to create a sphere-like view using qgis and the "world from space"-projection http://spatialreference.org/ref/sr-org/6980/ (essentialy an ortho-projection). ArcGIS wraps the shapes ...