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

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3
votes
2answers
453 views

WMS layers don't draw in QGIS or ArcMap but do in OpenLayers

WMS Map was published by myself in AutoDesk Infrastructure Map Server 2013. I can connect and load detials (properties / metadata) in QGIS Browser, ArcCatelog. I can load the wms into QGIS desktop and ...
0
votes
0answers
4 views

How to create a specific svg file with data from a feature

Here is a solution for whose want to create specific svg file depending on the feature data Language c++ / QT4.8.5, qgis api c++ 2.8.2 A svg file contains xml code In this exemple we put a specific ...
2
votes
1answer
160 views

Trying to set NAD 1983 EPSG 102631 in QGIS

I was able to find the right coordinate system online NAD 1983 Alaska But now I don't know what to do. I can't find the coordinate system on QGIS. When I choose the one I think is correct it warps ...
1
vote
2answers
36 views

is it possible programmatically to rotate a svg of the feature without rotate all feature

I am working on a project that need to move and update the shape of the feature of the layer. I am working in c++/ QT4.8.5 and qgis api c++ 2.8.2. In my Layer I have a lot of features, each feature ...
0
votes
0answers
9 views

QgsExpression using complex sql and python subsitution

I have a sql statement i am running in postgres fine and would like to transfer it to a QgsExpression mainly because I have loaded the layer in Qgis. My sql is: select column a,column b from table1 ...
3
votes
1answer
48 views

Projecting a world map on 6 segments to print on ball

Working with QGis and data from Natural Earth I would like to prepare a world map (1:50 000) for a globe that can be printed in 6 segments, which glued together build a ‘sphere’ (ball) according to ...
2
votes
1answer
180 views

Python Error while installing Cartogram

I am quite new to GIS and qGIS especially. I would like to install cfarmers cartogram plugin. From what I understand, this has to be done manually - so I 've followed the instructions from ...
2
votes
3answers
51 views

How to host QGIS threejs outputs?

Is there a free simple way to serve / host the .html files the awesome Qgis2threejs plug-in produces? I have tried using Google Drive as shown here and here without success. Also had same results ...
4
votes
1answer
33 views

Exporting Contours from QGIS into AutoCAD [duplicate]

I'm trying to export contour lines from QGIS into standard AutoCAD but I'm not having much luck. It does not seem to matter what type of file I select as the output during the contour creating (eg. ...
1
vote
2answers
25 views

Syntax error in parameter formula of field calculator funtion

I'm using a QGIS 2.8.1 in windows. Have some doubts with syntax when use string in python console. I want to use the field calculator funtion like: processing.runalg('qgis:fieldcalculator', input, ...
1
vote
0answers
24 views

Polygons within Polygons Spatial Analysis

I have a polygon layer of planning applications and I am wondering if anyone can give any advice and or has seen or written a blog post that might point me in the direction of creating relationships ...
1
vote
1answer
24 views

How to reduce points by proximity

I got a layer with over 4 million points. The distance between the points are 1 meter. How can i reduce the data so that no points have less than e.g. 10 meters between them?
0
votes
1answer
24 views

messed up shapefile attribute table text

I have a .shp file from AutoCad imported to QGIS (using _MAPEXPORT > text in AutoCad) and this is what happens to text in attribute table - example: {\Fsimplex|c0;O\Fsimplex|c238;Š\Fsimplex|c0; ...
0
votes
0answers
8 views

Tracing a raster layer in QGIS [duplicate]

I have a basic map I would like to trace into vector form in QGIS. The map is just a JPEG and has no coordinate reference data. Whenever I import it into QGIS, it ends up as a tiny speck at 0,0. How ...
0
votes
0answers
13 views

Qgis 2.10 unable to add a new feature in spatialite via sql function “GeomFromText”

Using Python code in my plugin the function in sql language "GeomFromText(POINT(X Y))" gives the following error: "OperationalError: no such function: GeomFromText" Plugin functions in previous ...
1
vote
0answers
25 views

About performance of qgis with big layer or a lot of layer

does anyone has a feedback on the performance of a big layer by exemple : I have a layer with 100 features, each feature contains specifics attributes with dynamic data, the data change each second ...
-2
votes
0answers
15 views

Interpolate precipitation Data on fly and save result in text [on hold]

How to spatially interpolate on fly large daily(365 days) rainfall data and save the resultant precipitation of particular desired point(lat, lon)
2
votes
0answers
41 views

Merge Line Segments based on their length in QGIS

I have a layer containing line segments which are connected by their endpoints (e.g. as within a street network). I'd like to merge (union) polylines within this layer into one feature until following ...
1
vote
2answers
28 views

Cut/Clip/Split a polygon with another polygon from same layer (Editing) - Qgis 2.8.1

To not have overlapping polygons/features I normally use a practice where I use one or more polygons to clip/shape other polygons. This is often much faster than tracing when adding polygons etc. I ...
1
vote
1answer
363 views

QGIS Invalid object name 'geometry_columns' QODBC3:Unable to execute statement

I was using Lisboa 1.8 with SQL Express and tables with geometry. Connections were working with 1.8 and are working with ArcGIS, so I know my tables and geometry are fine. I installed 2.4 Chugiak, ...
3
votes
5answers
1k views

Clip in QGIS 2.4.0 resulting in empty output files

I'm seeing the same problem to Clip or Intersection tool - QGIS giving empty files trying to use the Clip tool since upgrading to QGIS 2.4.0, but have not been able to fix the problem based on the ...
1
vote
0answers
10 views

GeoExplorer not display the associated table to a layer

GeoExplorer shows the table information associated with a layer of 2 ways: Information button: clicking on the map is displayed a tab corresponding to the polygon attributes where you click. Query ...
-1
votes
1answer
26 views

Paths with least elevation gain

I have a DEM of a city with numerous hills and a shapefile of the city streets. I want to find the five paths from a low point A to a high point B on the street network that involve the least ...
1
vote
1answer
17 views

SVG To Shapefile [duplicate]

Is it possible to draw out some SVG shapes in Illustrator or Inkscape and convert them to Shapefile using GDAL or QGIS (or something else perhaps?). I have an image that I can easily georeference, ...
1
vote
0answers
17 views

How to visualize updating lines of bearing from a point

I'm working on a project where I need to visualize a constantly updating line of bearing from a point, based on degree of rotation around that point. My plan is to design a line feature with an ...
2
votes
1answer
25 views

Recast data from one geographic standard to another

I'm working right now a project looking at medical labour supply in rural areas in Australia. I aim to use STATA for most of this analysis, but a change in geographic standards by the Australian ...
1
vote
1answer
18 views

Calculating field on insert (real time) using QGIS?

We use QGIS as a field application. We like to calculate with a input value and then also calculate with the result of the calculation Example: Liters: 1000 -> Liter per container: "this has to be ...
0
votes
0answers
20 views

How to add coordinates to an image in QGIS? [duplicate]

I use QGIS 2.10. I have a map image without any coordinate or boundary info. I need to convert it to kml file and before this, I need to add specific coordinate info for this map. How can I add ...
-1
votes
0answers
22 views

QGIS 2.8 printcomposer show image dynanic

I have a table with photo's, i now want to make dynamic map with discription en showthe photo. In the composer with atlas, so i can produce about 1000 pdf files Is this possible? The photo's are ...
0
votes
0answers
35 views

Deciding variables for image classification?

The results of an image classification may vary A LOT depending on the variables you use from the beginning. Number of classes, minimum class size, sample interval, atmospheric corrections, ...
2
votes
0answers
17 views

How can I use a DBF layer in an R script in QGIS?

How can I use a DBF layer in an R script in QGIS? For example, I can input a vector by using ##Layer=vector, and a CSV table with ##Table=table, but it will fail if the table is based on a DBF file. ...
0
votes
1answer
36 views

How can i calculate the distance to the nearest five neighbors for a polygon layer?

Data set (shape file) contains polygons. How can I calculate the distance to the nearest 5 polygons in the data set in QGIS?
0
votes
0answers
18 views

32Bit QGIS 2.10 Problems with Gdal WMS TMS google maps layer

I have been using gdal wms layers to view various basemaps in QGIS. I am using this technique rather than open layers because this I can reproject gdal WMS layers as needed. When I get close to the ...
1
vote
0answers
34 views

Why I see a gap between ESRI Robinson WGS84 (EPSG 54030) VS QGIS Robinson WGS84 (EPSG 54030)?

Does anybody know why there a gap appearing between two point layers create with ESRI and QGIS when I a reproject, from the same source file, to Robinson ? The source coordinate system and ...
2
votes
0answers
18 views

How to show only some layers in the QGIS legend

I hope this is still kind of a QGIS related question. My QGIS 2.8.2 standalone app provides several decorating layers (e.g. cartographic grid, background layers, reference points) which should be not ...
1
vote
0answers
11 views

Zonal statistics shifted

I am working with QGIS (newbie). I have a raster map with 0.5degrees resolution. I created a 0.5degrees width grid layer and I compute zonal statistics from the raster. My problem is that it seems to ...
1
vote
1answer
52 views

Is it possible to change the geometry without startEditing the layer

I am working in c++/QT 4.5 with the QGis 2.8.2 API. I had to change the geometry of features in a layer each second. Each second new data comes from the Ethernet connection, the application gets the ...
3
votes
2answers
1k views

How to interactively get the coordinates of a point in QGIS

I have a shapefile with a single layer of type point. It is in the google CRS (EPSG:900913). When I use the 'Identify Feature' tool it gives me lots of information about the point clicked on, but I ...
2
votes
0answers
18 views

QGIS Set Composer Legend to shrink the font size to fit

QGIS 2.10.1. I have read that it is "impossible to make the legend smaller then its contents". Is there a way to set the legend to shrink the font size when re-sizing the bounding box? Or when you ...
4
votes
1answer
168 views

Grass NVIZ has no output in QGIS 2.8.1 ubuntu 14.04

I am trying to use the Grass7 NVIZ algorithm from the QGIS 2.8.1 toolbox, on ubuntu 14.04. I have enabled Grass7 in the QGIS processing preferences. I have compiled Grass7 from source, and Grass ...
6
votes
3answers
1k views

Rendering and Labeling Shapefile with PyQGIS

I've been running into a few problems working with the QGIS API for python. I've gotten more comfortable working in the python console in QGIS but I run into problems when I try to run the code ...
3
votes
2answers
124 views

Way to find minimum value from a group of values - QGIS?

I'm wondering if there is a way to find the minimum value of a group within QGIS? Basically I need to find the minimum distance of each unique value in a table of about 5000 records. I can do the ...
3
votes
1answer
64 views

What projection to use to get a game map into QGIS?

I have built and maintain a SWTOR game map atlas. At the moment, it's all static jpg maps, but I would like to get the info into an actual GIS software to get more functionality and make my website ...
3
votes
1answer
301 views

How to compute average slope and area-weighted average slope?

I am learning GIS for use in hydrologic analysis. Related to computation of overland flow there are two types of slope that I would like to be able to obtain from GIS. The first is average slope for ...
2
votes
1answer
48 views

How to create flow maps in Qgis

I have several records from a survey and would like to show flow map from places mentioned in the survey. I have all places mentioned georeferenced and some records mentioned no places and others ...
3
votes
0answers
20 views

How to randomly select three points in each polygon?

I have two layers: first layer includes polygons of districts, second layer containts points (phytocoenological relevées). The goal is to create a new layer that will contain max 3 randomly selected ...
1
vote
2answers
38 views

About defining coordinate reference system

I have been wondering about the following issue for several years. In ArcGIS and QGIS you can add data on your map and it aligns perfectly even when the Coordinate Reference System (CRS) is not set. ...
3
votes
1answer
98 views

Where did Processing Algorithms go?

I have recently installed QGIS 2.8.2 on my Windows 8.1 laptop with the stand alone .exe installer. The processing toolbox is missing the GDAL/OGR, GRASS, QGIS algorithms, Saga and the Orfeo Toolbox ...
1
vote
1answer
41 views

How to find the intersection length between two polygons using python

I have two polygons and i want to find the intersection line length between these polygons. for geom1,geom2 in itertools.permutations(selection,r=2): intersection ...
3
votes
1answer
697 views

How calculate areas between certain contour lines in qgis?

Sorry for asking a question which I found in similar ways already here, but I am trying this for days and just got no result: How do I calculate the area between certain contour lines (e.g. 0-800, ...