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

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3
votes
1answer
119 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
979 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
290 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
1k 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
535 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
185 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
162 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
1answer
953 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
252 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
464 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
975 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 ...
3
votes
3answers
2k 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
320 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
971 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
99 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
104 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
137 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
438 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
61 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
33 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 ...
14
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
343 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
307 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
451 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
94 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) ...
4
votes
2answers
903 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
68 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
97 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
469 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
200 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
42 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
400 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
948 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
224 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
142 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
351 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
152 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 ...
2
votes
2answers
1k views

How can I link java with QGIS?

I want to create a Desktop project on Java which shows radiation dispersion. How can i Link java with QGIS? Is there any tutorial site i can get reference from?
2
votes
1answer
227 views

How to connect waypoint pairs and calculate length?

I want to make a path out of points and calculate the distances of each single line. I have a point layer with waypoints of a research vessel. The way points have in the attribute table a date and a ...
4
votes
2answers
253 views

Connect to PostGIS using SEXTANTE in QGIS

I have a localhost PostGIS database that I would like to use with SEXTANTE in QGIS. I can connect to the database just fine using "Add PostGIS layers...", but when I try "PostGIS execute SQL" in ...
1
vote
1answer
39 views

How to report issues with QGIS documentation?

I stumbled across a gotach while installing mod_fastcgi on MacOs 10.8 (mountain Lion) -- there is a bug in 10.8 in the apache build env which breaks the install instructions here: ...
4
votes
2answers
468 views

Can't select layer to upload to GPS

I'm trying to upload a vector layer to my Garmin GPS unit. I've saved it as GPX (WGS 84); opened the GPS Tools dialogue in QGIS 1.8; selected the "Upload to GPS" tab; and clicked on the "Data layer" ...
0
votes
0answers
509 views

QGIS 1.8.0-Lisboa DBmanager (OSx) can't connect to remote PostGIS 2.0.2 database (Debian)

The PostGIS database is remote but I have made changes to the Postgresql config files and can access it remotely via pgadmin. When I open DBmanager in QGIS I see a note on the bottom that says ...
3
votes
1answer
656 views

Handle add new feature event and/or access feature before commit?

Is it possible with PyQGIS to catch "add new feature" event before commiting changes on the layer? or at least to access new features before commit.
8
votes
2answers
457 views

How to avoid duplicate GIDs when copying features from one PostGIS layer to another?

When I enter new elements (features) in another Postgres layer, I can do it in two ways: Drawing new element(s) (with 'Add feature') which I do rarely or Copying (or cutting) some elements from ...
0
votes
1answer
183 views

Postgresql on Ubuntu Server and QGIS [closed]

Complete newbie... I taught myself the basics of GIS on the job with ArcGIS 9.3. I have been plating with QGIS and have gotten the basics down on both. I am not well versed in the terminology related ...
3
votes
0answers
121 views

Is there a tool for automated quality assurance for vector data captured on raster data?

I wonder whether is any tool(or script) in ArcGIS or QGIS which allows to make an automated quality assurance for vector data captured on raster data? vector data on binary raster:
1
vote
1answer
122 views

“ERROR: invalid input syntax for integer” importing data from Spatialite into PostGIS through DB Manager

I am trying to import data from Spatialite into PostGIS through drag and drop in DB Manager but all I received was an error: Feature write errors: Creation error for features from #1 to #202. ...
3
votes
1answer
174 views

How to display only one representative contour line in legend?

I have a layer of topographic contour lines, graduated by color (using QGIS). My legend wants to display every level and its color. This is not feasible. I need to simply show one representative line, ...
6
votes
2answers
1k views

Why do my Shapefiles not align correctly?

First: I'll summarize what I understand so far so please confirm or correct me. When On-the-Fly is selected a layer is re-projected from that of the layer's CRS to that of the project CRS, IF ...