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

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4
votes
1answer
443 views

How to measure the distance of multiple points to a line

I have two shapfile in QGIS to which I am trying to find the distances between. I have a shoreline which is a vector line and then I have hundreds of data points in the ocean. What I am trying to find ...
2
votes
0answers
429 views

Transform RGB-Map to CMYK (qgis, opensource tools)

I want to print a map I made with qgis. For the print I need CMYK-colors but the print-composers pdf-output is RGB. How can I convert the RGB-map/-pdf to CMYK?
1
vote
1answer
161 views

How to run “create mask” from the console?

There's a plugin called "create mask" for qGIS and trying out some simple scripting from the Python console. I would like to call it after I select the vector features I want, then do more related ...
6
votes
1answer
83 views

Is there a way to select only a certain polygon for editing?

I have a spatialite data base with 4300 polygons contained within. I wish to be able to edit the polygons but once i have highlighted the Polygon from the attributes table i find it hard to edit the ...
1
vote
0answers
60 views

Avoid rounding of coordinates in pyQgis

If I get the coordinates of a polygon in qgis by x = geom.asPolygon() It rounds off the coordinate from i.e. -27,200,334.86 to -2.72003e+07 How can I avoid that?
0
votes
2answers
227 views

loading CanVec directory full of .shp files

I'm totally new to QGIS, and trying to view a Canadian Topo map as published on an iMac - I don't want to change it. ...
1
vote
1answer
87 views

How do you Select an existing vector Layer and Edit it, using python?

I'm developing a small plugin that needs to be able to select a vector layer programatically based on what layer the user has selected. However I'm not sure how to do so. I believe I found the two ...
3
votes
3answers
166 views

QGIS Python Intro Text

After reading replies regarding starting a mapping business, I think I'd better read a Python book. Any intro-level Python books to recommend? Mila
5
votes
2answers
2k views

Total of attribute field of point layer per polygon layer

I have a polygon shapefile of many lakes, I also have a point shapefile of locations on those lakes where fish were caught. The point shapefile contains the attributes: Fisherman_iD, Fish_Caught, ...
2
votes
1answer
172 views

Setting coordinate systems in QGIS: “transform error caught”

I'm learning how to use QGIS (v 1.8.0 "Lisboa") on Mac OS 10.6.8. My goal is to create a simple county map of Illinois using the base data shapefiles available from the Illinois Natural Resources ...
1
vote
1answer
107 views

Why can I only see a default list of KML attributes in attribute table?

I converted a shapefile to kml using ogr2ogr. Glancing at the output, it looks correct -- it has a <Schema ...> and each <ExtendedData> references the schema (I uploaded a snippet here). ...
9
votes
3answers
795 views

How to Display Overlapping Lines?

I have multiple line layers that represent bus routes and many of the routes overlap (i.e. near terminals, transfer locations, etc.) Is there a function in Qgis which will display both features ...
0
votes
1answer
260 views

QGIS not Printing to PDF [closed]

Simple QGIS 1.8.0 not printing to PDF. Suddenly stopped. Is this an error or something. the resultant PDFs are blank pages. When i file print and use a pdf printer it creates blank docs. when i ...
3
votes
1answer
153 views

How to select features by matching attributes of two SHPs?

I have one line shape file with lot of road sections and a point shapefile, some of these points are outside my area of interest. The files have one attribute in common and I would like to do ...
4
votes
1answer
1k views

QGIS Zoom from python console

What are the commands to apply all types of zoom (full, on selected layer, etc.) in python console? I'm searching both on pyqgis cookbook and API documentantion, but I'm not finding anything ...
1
vote
1answer
317 views

Rasterize vector with gdal

"I would like to calculate the Euclidian distance from a residence to a public service of interest e.g. the distance from a residence to a green space (as the crow flies) in QGIS. After browsing the ...
2
votes
2answers
2k views

Extract coordinates from vector layer in PyQgis

In Qgis, I have made a polygon, and from that polygon I have made a vector grid via research tools-> vector grid. The grid covers the entire polygon. Now I want to extract these grid points in the ...
8
votes
1answer
585 views

How to create a Human Trafficking Heatmap in QGIS?

I'm trying to create a heatmap with about 325 points distributed around the city of Houston. (FYI Houston is a major human trafficking in the US: a title shared with LA and Atlanta depending upon ...
2
votes
0answers
211 views

How to use Memory layers in QGIS plugin to store results of Geoprocessing tools

I'm building a plugin to perform Multi Criteria Analysis (yes another one...). As part of my workflow intersecting vectorlayers is needed. I use QgsOverlayAnalyzer.intersection (a pity union is not ...
1
vote
1answer
176 views

Is the QGIS plugin repository broken?

I'm connected to the QGIS plugins repository, using QGIS 1.8.0 on Windows 8.... and although I can see a total of 119 available plugins, I can't see Sextante anywhere in the browser. I tried ...
5
votes
2answers
1k views

Does anyone know the proj4 Coordinte Reference System command line for Rectangular Polyconic Gores?

I am a GIS beginner using QGIS 1.8.0 I am trying to transform a world map from the standard WGS84 Coordinate Projection System to a set of rectangular polyconic gores, with a gore count of 12. ...
1
vote
1answer
288 views

how to find share segments between two shapes (line) using QGIS?

I have two line shapefiles. I want to find between them, where are located all share segments and extract the new selection shapefile. Can anybody help me? I am using Quantum Gis. I know that in ...
2
votes
0answers
541 views

z-Coordinate and interpolation plugin in QGis

I've a csv file that includes weather stations locations (x,y,z) and precipitation values. I loaded the file by using add delimited text and then converted it into a point shapefile WS84. By using the ...
4
votes
1answer
1k views

How to customize label color in QGIS: Data defined label settings? Expressions? Both? What are the steps? [duplicate]

Updated to show more current screenshot and clarified the question (Which tools? What are the steps?) I'm learning QGIS (1.8 "Lisboa" for Mac). On the QGIS Layer labeling Settings window there is a ...
4
votes
3answers
3k views

How to create lines between pairs of two coordinates?

I have a table with pairs of points. Out of that I want to create a line layer (that keeps all attributes of the table). One line for each raw from point to point. I want to calculate the length of ...
2
votes
1answer
398 views

Why are JPG files invisible in Georeferencer?

I want to georeference a jpg file (map) with QGIS 1.8.0 on a Windows 7 (64 bit) machine. The georeference window opens, but the map is not visible. When converting the jpg file into a tif file (e.g. ...
6
votes
2answers
1k views

Tilemill Dynamic Tile Generation

I have recently used Tilemill and I wish to implement it for dynamic tile rendering.As I've seen an CartoDB doing in cloud system,they can query & generate dynamic tile for request with UTFGrid. ...
2
votes
1answer
108 views

Where can I get a comprehensive list of Rules expression operators?

I'm selecting and styling my points layer on a contour map of Philadelphia using Rules Based Styling. (see: Can I use rules based rendering in QGIS to select features?). The filtering process using ...
0
votes
1answer
108 views

How Could I Calculate Shortest Path ?

I am working on QGIS - 1.8 Version and frequently getting an error while using Road Graph and Shortest Path Opetions. Kindly Suggest or provide solution.. With Regards Prashant Persai
1
vote
2answers
143 views

Generating new shp files according to attribute in QGIS

I know that it is possible to color a vector map by attribute. I separated a map into 4 colors based on an attribute and now I want to generate a new map for each color. Is there a way to do this in ...
3
votes
1answer
514 views

How to make survey lines within polygon?

I am trying to figure out how to make survey lines within a polygon. So first I make a polygon. Now I need to fill this polygon with lines, where I can choose the spacing between the lines, and the ...
2
votes
1answer
64 views

QGIS VPAT; Section 1194.21(c)

I am attempting to fill out a VPAT for QGIS so that it can be made more accessible in the federal IT environment. I could use some help and wanted to explore this venue as a means of getting it. If ...
2
votes
0answers
34 views

Automatic insert of project name into database

For every layer I've a field in my postGIS database that should be filled with the name of the current project and today I do this manually. Is there a way to do this with the Commands that can be ...
15
votes
2answers
2k views

Creating Thiessen (Voronoi) polygons using lines (rather than points) as the input features?

I have a set of line features inside a particular polygonal boundary. For each line, I'd like to generate a polygon inside which every possible point is closer to the given line than to any other line ...
1
vote
1answer
422 views

QGIS Sextante Python UnicodeEncodeError

I have some issues with Quantum Gis 1.8. When I try to use shapes to grid (sextante-saga tool) I get the following error (comes up when I try to define the new grid file name): Fehler bei der ...
1
vote
2answers
451 views

How to mask out features outside of the Coverage Layer for Atlas plugin? [duplicate]

Using the Atlas plugin for qGIS how do I set the coverage so that it will only highlight the feature(s) I want but still show the surrounding features as grayed out areas? This would have been easy ...
1
vote
0answers
580 views

Lines as Great circles on a map

How can I get line features to appear as great circles on a map, instead of straight lines? Thanks,
2
votes
1answer
105 views

QGIS mixing up CRS

I´ve just started working with QuantumGIS for my thesis. I ordered shapefiles with the CRS: ETRS 89 UTM Zone 33N, but QGis layer properties now shows the layer has a different CRS (namely SWERE99 TM) ...
5
votes
2answers
1k views

QuantumGIS 1.8: how to define bounding box within Add WFS Layer dialog

I use QGIS 1.8 under WIN XP in Standalone Installer Version. I need to limit the extent of the data to be downloaded via WFS because of the large amount of data in the requested layer. In ...
2
votes
0answers
82 views

QSpatiaLite: Cannot create table

I am running QGIS 1.8 (SpatiaLite 3.0.1) and QSpatiaLite 6.0.1. I have a spatial table EventPrecise (with geometry column p in EPSG:4326). I want to join this table with another, non-spatial table ...
3
votes
0answers
112 views

QGIS Workflow Problem [closed]

I have 3 SpatiaLite layers (one without geometry but with fields that need to be filtered, one with points and one with polygons, both without any non-geometry fields) that need to be combined to a ...
4
votes
2answers
542 views

Setting coordinate systems in gvSIG: Is the workflow similar to QGIS?

I am still learning how to use coordinate systems and projections, but I hope this basic question will be easy to answer. My goal is to be able to use either QGIS or gvSIG to create a simple county ...
5
votes
1answer
303 views

How do “join field” and “target field” work?

New user. This should be simple, but I can't figure out how to perform this basic join in QGIS. (It works in Cartographica.) My shapefile (IL_BNDY_County_Py) has two fields/columns in its attribute ...
0
votes
0answers
52 views

How to extract elevation data from DEM along a polyline [duplicate]

I've been trying to use qGIS to extract and save as an attribute the data elevation along a line, knowing that something similar is available in ArcGIS using the Spatial Analysis tool. So far, ...
2
votes
1answer
460 views

QGIS Routing between two Points without Roads

I'm using QGIS 1.8 and i need to analyze possible routes for roman roads. Is there a Possibility to show routes which comply special criteria, e.g. straightest way between two points, or path which is ...
2
votes
1answer
1k views

How to convert lines from dxf to polygons?

I have several dxf files. Each file, contains the 0 layer. The 0 layer contains lines (which make a closed polygon). In each dxf the lines have their color and line width. I do not have autocad or ...
4
votes
1answer
274 views

How to auto-start a pyQGIS thread?

having build some (two) minor plugins, it's now time for me to link a few (perl-) applications to qgis. As there is no perl-interface in qgis I thought the best way to link both worlds together is a ...
3
votes
2answers
155 views

I am unable to draw a shape layer

When I add a new shape layer or want to edit an existing one, nothing is happening. I even don't see the dots where I'm clicking. Maybe the problem is I deleted some layers (by opening the .qgs as a ...
1
vote
1answer
411 views

How to Georeference a tiff with correct coordinate system

I am having difficulty in georeferencing an existing tiff (already has georeference information - but is out of alignment). Using the georeference plug-in I can create the map's GCP in the 4 corners ...
2
votes
2answers
163 views

QGIS 1.8 on Ubuntu 12.04 doesn't transform CRS properly

I have a weird QGIS-Problem that only occurs in Ubuntu 12.04, but not in Windows 7. I've also tried this on different Ubuntu-Computers. When I try to transform a layer with WGS84 to a different ...