Tagged Questions

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

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5
votes
2answers
327 views

10 GB Raster Aerial Image in Quantum and POSTGIS

I have a problem... I have been successful in uploading the raster in postgis but when I access it through Qgis. it does not open even after several hours. I have 10GB aerial image raster and ...
0
votes
0answers
116 views

How to merge raster quadrangle tiles in qgis?

I've downloaded some dem tiles from here http://www.granit.unh.edu/data/search?dset=dem/dem174, which I'd like to merge into a single smooth digital elevation model usinq QGIS. So far I've tried ...
0
votes
1answer
173 views

Label polygons in MapInfo like QGIS?

I was wondering if there is a way to angle Polygon labels in MapInfo like it's done in QGIS (see image link below). Thanks, Alan
2
votes
2answers
586 views

Styling OS Vectormap Local in QGIS?

I am attempting to style Ordnance Survey Vectormap Local on QGIS 1.8.0 by using the styling sheets suplied by Ordnance Survey. The styling sheets are available from the OS website ...
1
vote
3answers
137 views

How to search for several different features in the attribute table?

I guess my problem is a quite simple one, but the query builder and I have our difficulties, so maybe someone can help me. I have a long attribute table in QGIS and am trying to extract about 200 ...
0
votes
1answer
117 views

Quantum GIS Installation Failure

I installed GSL 1.16 & GDAL 1.10, then I proceed to install QGIS 1.8.0 After running the .pkg(installer) I get the following message. Failure The GDAL 1.9 framework is required. Does this ...
1
vote
1answer
163 views

How to make grid lines opaque so just lat/long coords are on map border?

Can any one help me with adding graticules to my map? I have managed to add a lat/long grid over my map, however I want the grid lines to be opaque with just the lat/long coords on the map border - is ...
1
vote
1answer
560 views

How to create filled contour lines in QGIS?

How can I create contour lines that are filled with a graduated symbol usinq QGIS? In ArcGIS for Desktop I can do this. What about in QGIS?
0
votes
1answer
31 views

Can't get CRS transformations to work with scalie

No matter what I do I can,t seem to be able to transform several shape files (all vector) to a CRS that works. What is recommended for British Columbia for forestry purposes is NAD83 BC Albers. ...
1
vote
2answers
398 views

What is the equivalent of arcpy “Con” in QGIS and/or R raster-package?

I'm looking for an equivalent of the conditional expression "Con" from arcpy in an open source spatial analysis package. I'd prefer to use QGIS or R. To provide some additional detail, I need to ...
1
vote
1answer
134 views

How can I turn QGIS into a simple hiking planner?

I'd like to try and turn QGIS into a simple hiking planner. I have found and worked out how to import OS raster mapping at the correct scale and how to add freehand vector lines to the mapping, which ...
1
vote
2answers
70 views

Adding 'freehand' data to raster mapping in QGIS

Having just worked out how to import raster mapping into QGIS at the correct scale, I'd like to now add useful information to the map like marked routes, labels etc. How can I do this in a 'freehand' ...
1
vote
2answers
591 views

How do I import OS raster tiles into QGIS at the correct scale?

I have some tiles of OS raster mapping and their associated TFW georeferencing files. The GR files are in the same folder as the raster data and have the same names, ie TQ21.tif/TQ21.tfw. In QGIS ...
1
vote
1answer
139 views

Why does QGIS generate Shapefiles without DBF?

I need to output shape files for archiving, which requires generating .shp, .shx and .dbf files. When I save a layer as a shape file it generates the first two, but not the dbf. All the help I can ...
0
votes
0answers
223 views

Why does QGIS not show my new geometry columns?

I am trying to connect a few PostGIS Tables to Quantum GIS. The problem is that the geometry columns QGIS is showing are not the ones from the PostGIS database. QGIS shows me some columns I used to ...
4
votes
2answers
963 views

How to use map composer in a stand-alone script?

I'm trying to follow the map rendering section from the pyqgis cookbook, but I'd like to test this as a standalone application. I can do the first part, using simple rendering, but I'm a bit stuck ...
2
votes
3answers
144 views

How to create a raster from scratch

I realize this isn't a geographic question as I'm not trying to make this into a geographically placed image. But I hope you all will know how to do this. I want to make a raster from scratch. I ...
1
vote
0answers
61 views

How to fix contour lines which look like a mirror image of the DEM?

I was trying to create contour lines in QGIS 1.8 for a DEM I have, but it's creating it in reverse. The contour lines are sitting on top of my DEM like a mirror image. I was wondering if someone could ...
0
votes
0answers
190 views

Why is Field Calculator Returning NULL for $x and $y?

I am trying to include XY coordinates in the attribute tables of several of my vector files. I have tried two methods; first I used $x and $y in the field calculator (which I've used before and ...
2
votes
0answers
19 views

Sum vector data correlating with a second vector layer [duplicate]

There are a lot of questions very similar to mine, but I couldn't find one that accurately described what I want to do. I am working in QGIS. I have one vector layer which, among other attributes, ...
0
votes
1answer
589 views

How to fix “Connection failed - Check settings and try again” when connecting to PostGIS?

I have Postgres running via Postgres.app on rails already and am trying to connect QGis to the database. PostGIS is working already. (questions already found online deal with this issue only) I do ...
2
votes
1answer
144 views

How to convert a line to points?

I'm working with QGIS and I want to convert a line into many points, does someone know how? Thanks.
2
votes
1answer
152 views

Where can I find the data that QGIS used to custom its menus as well as it's toolbars?

I have noted that QGIS uses some data to restore its menuitems as well as its toolbar items everytime when it is started.And I have being trying to hunt them out in my hard disks but sadly ...
0
votes
1answer
153 views

How to merge polygons into a single item where an attribute is same?

I have a shapefile of a area .It consists of list of fields in which sub locality is also a field.Under the sub locality field all the areas are common say for example: perungudi,perungudi,perungudi. ...
2
votes
1answer
628 views

How to create a QGIS Action which loads a raster?

I am following an article here:Actions HowTo , specifically the piece about an action to load a raster: Python type Add Raster Layer ...
2
votes
2answers
299 views

Import Points with WKB format to QGIS

I have a .csv file with population data according to specific locations (Points). My problem is that all locations are given in WKB format like that: ...
4
votes
0answers
66 views

What's the best way to add Tilemaps to QGIS without having to use Webmercator? [closed]

I'm looking for a good way to add tilemaps in qgis that are either in a custom projection or that I can reproject in qgis. I have used the openlayers plugin to add basemap layers, but it forces me to ...
1
vote
0answers
74 views

How can I maintain MapInfo GRC file attributes in QGIS/GDAL?

I am trying to manage a classified MapInfo grid file in QGIS - I'm wondering if anyone has any experience with maintaining the attributes of the classified grid? QGIS seems to assign them just a ...
1
vote
0answers
239 views

Shapefile projection issue - layers not lining up [closed]

See below for screenshot. The purple rectangle should line up with the green rectangle in the top right (OpenLayers Google Physical layer) and the tan points. I was sent this shp and given the ...
0
votes
1answer
50 views

How to set layer symbol and layer name side by side in QGIS Composer?

When I add a legend in QGIS Composer, the layer symbols are set below each layer name. Is there any way to have them side by side? This is what I get: "LayerName" [layer name] ~ [layer ...
7
votes
2answers
364 views

Is there an open source alternative to ArcGIS for Desktop's Integrate tool?

I need to snap about 1000 lines in one layer to the lines in another layer (there are about 5000 lines in the second layer). The lines to be snapped are about 15 map units away from the base layer ...
3
votes
2answers
404 views

Is it possible to embed QGIS layer styles in a Spatialite database?

Spatialite is a great alternative to shapefiles - but how could I store the QGIS layer style together with the data so that it has a default style? For a shapefile I would just save a [name].qml with ...
0
votes
1answer
116 views

How to Resize the Qgis Main Window from python

I would like to write a plugin that simply resizes the qgis main window to make it small. How can I access the qgis main window through the qgis api? Use Case: We are having problems with qgis taking ...
1
vote
2answers
303 views

How to add a dynamic timeline to the QGIS canvas?

I am using the plugin Timemanager which works really great but there is one thing I'd like to improve. Instead of displaying the date and time on each frame, I would like to display a timeline ...
0
votes
1answer
264 views

How to convert OSM polyline data to polygons?

I just now downloaded OSM data .I am having the data as polylines. I want that polylines as polygons is it possible in Qgis?below I also posted the screen shot of the polyline also.
2
votes
1answer
490 views

Can Tiff files from ESRI Geodatabase be loaded into QGIS

I have been able to load an ESRI geodatabase which contains shape files into QGIS, however when I try to load a geodatabase containing tiff files I get an error message saying ...."is not a valid or ...
0
votes
1answer
141 views

eVis-Plugin centers mapwindow on coordinate origin

I have a QGIS-project with layers loaded from a postgis-database and also some shapefiles. I use the eVis-Plugin to display pictures. The displaying is working fine but after clicking on the geometry ...
3
votes
1answer
120 views

Field Value Mapping QGIS

I am wondering if there is a way to do field value maps that are filtered based on another attribute field? I know how to associate value maps, but not that are connected to another field. I have ...
0
votes
1answer
651 views

How to count number of polygons inside another polygon layer?

I am looking for a tool in arcgis 10.1 Qgis or R that allows me to count the number of polygons that are inside specific areas (defined also as polygons). My data consists in: 1 shape file with ...
2
votes
1answer
152 views

Is there any way to find the shortest distance from a point to a line?

I´m working with QGIS 1.8.0. I have a map divided into many features (thousands of small rectangles) and I have a point at the center of each of those features. I also have a map of the transmission ...
2
votes
0answers
200 views

How to handle crashes on save causing “Project file read error: unexpected end of file at line 1 column 1 for file [pathway]”?

QGIS 1.8.0 Tried to save a project and as I saved it gave me the "QGIS has experienced an error and needs to close" Next time I went to open the project I got this (well I was going to post an image ...
3
votes
1answer
58 views

Does Quantum GIS recognize QDGC information?

Good morning! So a bit of background on what I am working on: We are in the process of assisting a wildlife institution in South Africa with trying to take their information and surfacing it in a ...
1
vote
1answer
104 views

How to write a QGIS Action which opens a PDF from a server?

I need to open a PDF from an action in QGis. The PDF rests on a server, not local. So far I tried this (as Python): from PyQt4.QtCore import QUrl; from PyQt4.QtWebKit import QWebView; myWV = ...
0
votes
1answer
173 views

How to convert a .rik to .tif?

I have a quite large high-resolution map in a format called .rik from the Swedish land survey agency. I want that whole high resolution file in different format that can be used to print a map from a ...
2
votes
2answers
337 views

Is the derived area/length/xy values of a polygon/polyline layer in QGIS usable?

I have a raster that is projected to a state plane CRS and I am adding polygon/polyline shapefiles that are projected to WGS84. On the fly transformation is set to reproject to my raster CRS. When I ...
1
vote
4answers
163 views

What units are my coordinates in?

I opened a georeferenced NAIP photo to a new project in QGIS. The coordinates were expressed as: 2199240.6, 616858.7. The same point in Google Earth was expressed in degrees, minutes, seconds, as ...
1
vote
1answer
97 views

How can I create a basemap from an NAIP image using QGIS? [closed]

I unzipped the image and loaded it in QGIS as a raster. Now, how can I turn that image file into a basemap that lines up with a specific coordinate system?
1
vote
3answers
95 views

How can I create a simple basemap in QGIS that will allow me to trace a polygon with an accurate projection?

I need to find an aerial photograph, create a new vector layer, trace several fields in this aerial photograph, and find random coordinates within these polygons. I first tried this with the Google ...
0
votes
0answers
66 views

How to change API version from 9.0 to 8.1 to load PyGIS

Traceback (most recent call last): File "", line 1, in RuntimeError: the sip module implements API v9.0 to v9.2 but the qgis.core module requires API v8.1
1
vote
0answers
41 views

Why does exported map from print composer differ from map canvas? QGIS 1.8.0 [duplicate]

I have a small project consisting of a Google maps satellite open layer with two new shapefiles overlaid on it. I have then used print composer to add a grid and some labels. I have also selected lock ...