Tagged Questions

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

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0
votes
0answers
45 views

Point to Polygon [duplicate]

Possible Duplicate: Create new polygon layers from postcodes latitude & longitude I'm running QGIS 1.8.0 I have a list of points that I need to convert to one polygon. So far I have ...
0
votes
1answer
946 views

Transform Shapefile from WGS84 to NAD83 using QGIS? [duplicate]

Possible Duplicate: How to reproject a vector layer in QGIS? I have some shapefiles whose CRS is WGS 1984 and I have some shapefiles whose CRS is NAD 1983 State Plane Illinois East. I want ...
6
votes
2answers
1k views

How to compile QGIS with GRASS on Ubuntu?

I am on Ubuntu building qgis with grass plugin. I have build grass code separately and used --prefix to provide the path GRASS_PREFIX is /usr/local/grass-6.4.2 and GRASS_INCLUDE_DIR is ...
4
votes
1answer
140 views

Problem opening a shp in another application

I helped a colleague converting waypoints from a gpx file to a shape file. My colleague has only arcMap. I gave him the shp and when he opened it in ArcMap, it did not show anything in the attribute ...
5
votes
1answer
71 views

Geographic locators within Polygons

I have a list of geographic locators and a boundary file. In QGIS, is there any way merging them together to create a lookup saying this boundary contains these locators? Not the number the actual ...
7
votes
1answer
241 views

Why is QGIS 1.8 crashing when exporting to PDF?

I want to export for example this: but qgis crashes. Sometimes with an error message std::bad_alloc. But: My Mac has 8 GByte RAM and "just" 5,... something (of 8) GByte are used, moreover there is ...
6
votes
3answers
2k views

Delete multiple features easily in QGIS?

I have a vector layer being rendered in QGis. I want to delete various features in the layer. I'm currently deleting each node by selecting the node through node tool and then pressing the delete ...
8
votes
5answers
310 views

How to ensure uniform colour for DEMs?

This is a silly question, but one I've been trying to figure out for a while. I have two Aster DEM tiles, one next to the other. How do I ensure uniform colour for both?
2
votes
1answer
452 views

What is the easiest way to let a user upload overlayers to openlayers (Geoserver/Mapserver)?

I need to let a user upload vector layers he created with QGIS or MapInfo professional to my website (using OpenLayers as client and either Geoserver or Mapserver as WMS). What will be the easiest ...
2
votes
1answer
199 views

Road graph tool crashes, but works with sample shapefile [closed]

When I try to calculate the distance between two points using the "Road graph" plugin in QGIS (1.8.0-2, on OSX 10.8.2 ML), QGIS just crashes. It does work with the sample shape file from ...
6
votes
4answers
2k views

Why do OpenLayers layers appear shifted in map composer?

I'm having trouble with the OpenLayers Plugin of Qgis and the map composer: If I create an OSM-background layer and if I want to export this, the OSM-Layer looks perfectly all right in the normal ...
3
votes
0answers
148 views

Are there any known problems using GPS connection in Android version of QGIS? [closed]

I install QGIS both my netbook (windows win7 starter) and My tablet (android 4.0). I can used GPS option in windows version and I can save location points from GPS. However, I could not manage same ...
3
votes
1answer
587 views

Problem with generating contour lines and filled contours

I am trying to create contour lines and filled contours from a shape file of height points using the contour plug in (have tried other tools but with no success). The data is sourced from the UK ...
2
votes
1answer
795 views

How to correctly merge layers with overlapping polygons in QGIS/GRASS?

I have 4 vector shapefile that I would like to join/merge, without worrying about attributes. Here are the shapefiles. I would like to do an union and a spatial dissolve, but everytime I do a dissolve ...
1
vote
1answer
807 views

“Please ensure that the GDAL_DATA environment variable is set and try again” on Kubuntu 12.10

I'm having a problem loading the 'convert os gml to ogr' plugin in QGIS 1.8 running on (k)ubuntu 12.10. Basically, clicking the plugin prompts the error: "Please ensure that the GDAL_DATA ...
1
vote
0answers
298 views

Start-up error message QGIS 1.8 Couldn't load PyQt4

After successfully building QGIS 1.8 "Lisboa" on Windows 7 in 32 bit mode by following the instructions mentioned here I am able to start QGIS, however I get the following startup error message: ...
7
votes
3answers
2k views

How to extract slope from topographic raster map?

I am working on a project for a machine learning class wherein I extract features from a topographic raster map and then classify the traversability of the terrain. One of the features I need to ...
7
votes
1answer
1k views

Sort layers in QGIS table of contents?

When I load a bunch of layers into QGIS from PostGIS, they seem to load in reverse alphabetical order. Is there any tools or plugins that allow you to quickly sort the QGIS TOC in a different order? ...
10
votes
3answers
9k views

How to import coordinate data from excel into QGIS?

I have an excel file containing data collected over many years as latitude and longitude coordinates for archaeological sites - how can I import it into QGIS as a new layer?
2
votes
1answer
597 views

How to debug 'Layer is not valid error' from Python plugin?

I'm trying to understand what goes wrong with a QGIS python plugin. Basically I'm trying to render a series of POINT. The query works fine, at least giving it by hand from inside PostGIS DB: "SELECT ...
3
votes
3answers
1k views

Summing attributes intersected by under a radius

Apologies - new user. I am working with QGIS on Mac OS X and with shapefiles downloaded from the US Census Bureau that show population data by state and by county. How do I: select certain points ...
2
votes
1answer
117 views

How to close and fill Gulfs and inlets in QGIS or Grass?

I have a raster layer from which I extracted only zones with a certain color, then polygonized it with QGis. I just generalized the new vector layer in GRASS to smooth things a bit. There are many ...
3
votes
3answers
2k views

How to extract POINT from a [LINE|MULTILINE]STRING

I'd like to create a vectorLayer in QGIS to display all the points that form a LINESTRING or a MULTILINESTRING stored in a PostGIS DB. I think that I need to transform all points of LINESTRING (or ...
1
vote
0answers
61 views

calibrating vector line in qgis

I have loaded GPS points into a QGIS vector layer. I also imported a vector line from a dxf file which doesn't have georeferencing. I would like to fit in line geometry between the GPS points - how ...
4
votes
1answer
136 views

Measurement not correct in QGIS 1.8

I have a SHP file of sub-areas of U.S. counties (roughly about the size of a Census tract) that I've reprojected into a 'true distance' projection (World Equidistant Cylindrical) in QGIS 1.8. However, ...
1
vote
1answer
1k views

QGIS, how do you break segments of a polygon, ie break 1 polygon into 2 or more?

I have a polygon but would like it to be in broken up to put into different layers. I can't work out how to do this.
7
votes
1answer
262 views

How to debug a QGis python plugin

I'm trying to write a python plugin for QGis. I'd like to debug some DB queries and I need a way to display the result. I thought about using a popup to display it, but I don't know how to show a ...
10
votes
2answers
458 views

How to build a minimum convex hull crossing the 180 degrees line?

I've been building convex hulls for species that inhabit the Indo-Pacific (~ from 20 to -65 degrees of longitude). The problem I've encountered is that for the species that can be found on both sides ...
4
votes
1answer
543 views

Vector tools missing in QGIS 1.8 (Ubuntu)

I installed QGIS 1.8 on an Ubuntu 12.04 Precise Pangolin virtual machine. everything seems to work fine, but I don't get any of the vector or raster tools that (I assume) are part of the standard ...
2
votes
2answers
599 views

Why is Spatialite delivering “Invalid SRID” error message

Qspatialite in QGIS 1.8 (and also Spatialite-gui) delivers an "Invalid SRID" error message when I try to load shapefiles with a SRID value of 3814 (Mississippi Transverse Mercatur). The SRID is ...
5
votes
0answers
132 views

How to add shapefile name as attribute during merge? [duplicate]

Possible Duplicate: How to add field with filename when merging shapefiles with ogr2ogr? I have more 200 shapefiles with a unique name. I would like to merge all of these together and save ...
3
votes
2answers
710 views

set geotiff 0 values to nodata

Is there a way to set all the 0 value pixels on a raster to nodata using gdal or qgis?I world like to use fillnodata to fill some holes, but holes are set to 0,so I need to delete them first
7
votes
1answer
5k views

Is there are QGIS plugin to allow the 3d visualisation of geological borehole data similar to the functionality of Target for ArcGIS?

I'm very new to QGIS, I have started using it as my new company is not willing to pay for ArcGIS and Target at this stage so I'm hoping QGIS can substitute not just in the interim but for good. What ...
3
votes
1answer
269 views

How to create a line with start and end points which are in another layer in QGIS?

In my map, there are lots of points in layer A. I want to make a line layer B and I want to make start & end points of lines snapping to points in layer A manually. Can I use points of layer A as ...
4
votes
3answers
94 views

Left click then right click is treated as double click in Mac QGIS Layers

I am having an issue with QGIS 1.8.0 on my Mac where I left click then right click which gets treated as a double click if the timing is too close together and brings up the Layer Properties box. ...
4
votes
2answers
635 views

How do I set mmqgis create grid options?

I am having a puzzle about using mmqgis create vector layer option. I want to use UTM CSR this are my options. I want a grid of 20,000 meters in the east and north axis. Nevertheless i have an error ...
5
votes
1answer
412 views

Stats on individual grid points nearest neighbours

First, thank you for this extremely useful and easy-to-access forum! I have shp of points where each point is the centroid of the individual cells of a 1*1km grid (~ 500 000 points). For each of ...
1
vote
0answers
220 views

QGIS WMS using tile size restrictions

When I add a WMS layer with a tile size restriction (2048 2048) the resulting WMS datasource in the QGIS project file is ...
2
votes
2answers
2k views

Editing polylines in QGIS (extend, trim, fillet etc)

I was wondering, if its possible to edit lines and polylines in qgis, in similiar way as autocad commands "extend", "trim" and "fillet"? About how the commands for in Autocad, very shortly: The ...
2
votes
1answer
259 views

Raster Analysis - Identifying features from Raster

I have an IDW, tension spline and hill-shade rasters that show an archaeological landscape and from these rasters I want to identify new features which are seen in the landscape as depressions. And ...
11
votes
1answer
428 views

How to create text labels with background boxes?

I'm trying to create some custom labels for point features in a QGIS point vector layer, and I want to write a python plugin to do it. We need our labels to be presented with color tinted rectangles ...
2
votes
1answer
445 views

QGIS ->ArcGIS Server configuration possible?

Is it possible to connect a QGIS Desktop 1.8.0 to an ArcGIS Server 10.0 ? and of course publish services on it?. The configuration would be like this Quantum GIS-> ArcGIS Server 10.0 on Amazon EC2+ ...
5
votes
1answer
142 views

How to convert PostGis Table (Grid data) to Continuous field using Qgis?

I'd like to transform my Gridded Layer (generated form a PostGIS table of points) to a continuous and colored layer. How could I do this with Qgis or any other program? Many thanks and best regards, ...
4
votes
2answers
460 views

Edit Toolbar Became Disabled While Editing in QGIS

My edit toolbar became disabled while I was editing a layer in QGIS. I have closed the window and opened it again to edit, but it is still disabled.
2
votes
1answer
198 views

Sextante “temp” folder?

I have a german Windows and the problem is when I'm using sextante tools the log tells me that I have issues with the folder dokumente und einstellungen (C:\Programme\Quantum GIS Lisboa>saga_cmd ...
1
vote
1answer
73 views

Can't find the New label tools in QGIS

I can't find the New label tools in QGIS developed by sourcepole. I'm using QGIS 1.7.4. Is it a QGIS tool or a pluggin? Thanks!
2
votes
0answers
152 views

Sextante - SAGA- Shape to grid question?

I have a vektor shape (Index 1-5). After using the saga tool (shapes to grid) I'm getting a raster (values 1-5). The problem is that the NO DATA area is defined as 129. Is it possible to set 129 as no ...
1
vote
2answers
497 views

error message when clipping raster with vector layer

When I try to crop a raster using QGIS Clipper tool, I get the following error message: ERROR 1: Attempt to create 0x0 dataset is illegal,sizes must be larger than zero.. Why? The code QGIS generated ...
4
votes
1answer
723 views

Unit of $length in QGis Field Calculator

I'm calculating field of various features in my shapefile using QGis. I'm getting some sample length as 0.134914579766986. I want to know in what unit (eg: meters, km etc) is the above value ?
11
votes
3answers
3k views

Are there open-source alternatives to ArcGIS online that can be hosted on my own server?

I know this might be too broad topic. But I am looking for web-GIS portal similar to ArcGIS online that is self-installable (configurable) to be hosted in my private server. The main features should ...