Quantum GIS is a user-friendly, cross-platform GIS application licensed under the GNU General Public License.
9
votes
1answer
3k views
How do I calculate the latitude and longitude of points using QGIS?
I'm trying to figure out how to calculate the lat/long of points using the QGIS field calculator. Is there an easy way to do this? I saw a previous related question, but it deals with a more advanced ...
9
votes
1answer
2k views
How to control Image Output Settings in QGIS?
I am exporting a QGIS map to an image format. I would like to have control over the output settings of the image (dpi), as currently it is only exporting the images at 96 dpi. Does anyone know if this ...
9
votes
2answers
316 views
How to buffer a line with different distances for left/right sides
How can I buffer a line in QGIS using one attribute for the left side of the line and one attribute for the right side of the line? I am trying to buffer a river with its bank width, which is ...
9
votes
1answer
139 views
Is there a way to add system date in print composer?
Is there a way in the Print Composer of QGIS to create a label that will automatically update the date (systems date) instead of having a label that you have to manually have to update?
9
votes
1answer
333 views
How to convert fake donut holes in polygons to real ones?
I have this problem where I have to import shapefiles into our system which must be geometrically valid, but the software that everyone uses to produce them seems to output files where every polygon ...
9
votes
4answers
872 views
How to place elevation numbers on contours with uphill orientation and position?
I want to orient my elevation labels uphill. Is that possible? I'm currently using the labeling tool from QGIS (not that one in layer settings). I want the labels curved and uphill oriented (and I ...
9
votes
3answers
1k views
How to connect QGIS to SDE?
I read your amazing solution in this topic Is it possible to connect to ArcSDE using QuantumGIS?.
Unfortunately I'm not so expert in open-source products (we use only Esri suite) and I need to ask you ...
9
votes
5answers
3k views
Is it possible to connect to ArcSDE using QuantumGIS?
Is anyone aware of any plugins, or any other way to connect and view data from an ArcSDE database in Quantum GIS desktop?
9
votes
1answer
323 views
Is it possible to take automatically a “screenshot” of my selected feature in QGIS using Python?
I am implementing a tool which allows the user to create a profile of a feature (in my case urban parcels). Is it possible to automatically take a screenshot of this feature (displayed in a QGIS ...
9
votes
3answers
2k views
Divide a complex shape file into a grid
I have a decently detailed shapefile with polygon/multipolygon features (the file is about 500mb). It's actually a shapefile of the entire world, with the features representing coastlines. I need to ...
9
votes
1answer
100 views
Advanced labeling formatting (centered and different sizes)
I would like to place the elevation-number of a point in a different front size and centred under its name:
Is that possible?
(That is my actual labeling: label || '\n' || elevation)
Thanks!
9
votes
2answers
609 views
Is there a way to use “Select by Attribute” in QGIS using a python command?
is there a way to use the function "Select by Attribute" in QGIS using a python command? In my plugin the user should enter a value via a GUI and this value should be used in a function which selects ...
9
votes
1answer
126 views
How to find the buildings (polygons) a user can see from a given location (point) and orientation (angle range)?
I would like to retrieve the set of buildings I can see from a given location (point -lat,lng) and orientation (interval of angles) + certainly with a given depth (e.g. 100 meters). Ideally I would ...
9
votes
3answers
243 views
Contours: Interrupt contour lines beneath a elevation number
Is there a way to interrupt a contour line beneath a elevation number?
Thanks!
9
votes
2answers
275 views
How do I generate a large number of maps?
I have to make a large number (hundreds) of distribution maps of species.
I have a shapefile that contain the distributions for each species, and for each one, I would like to get a map as an image ...
9
votes
3answers
1k views
How to connect lines in a network?
I have a shapefile of lines and another of polygons. When two or more lines intersect a polygon they should be connected (snapped), but sometimes during manual digitization this doesn't occur. I need ...
9
votes
3answers
317 views
How to “clean” and vectorize a raster map?
I'd like to make use of a geological map as shown in the example below, which is only a pretty small and downsized part of the map, so editing/redrawing doesn't seem to make sense in the end.
My idea ...
8
votes
8answers
9k views
How to install QGIS on Ubuntu 12.04?
Has anyone had any luck with getting QGIS working on Ubuntu 12.04? I have tried the stable and unstable versions and with not luck. I also get the following:
"Some packages could not be installed. ...
8
votes
4answers
290 views
Where to start learning how to make maps with QGIS?
I have no skills in GIS, "map-making," or any other map program. Been a county planner for 25 yrs, where there was always a "drafting" staff. I'm in another agency now and need to be able to produce ...
8
votes
3answers
7k views
How to merge multiple layers to one layer?
I've imported several shapefiles which where exported from an Mapinfo .tab. Several tab files are imported resulting in 20+ layers.
Afterwards I want to export it to geoJSON; but I'm reluctant for ...
8
votes
5answers
231 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?
8
votes
3answers
1k views
How to do hydrological modeling in QGIS?
Can someone please direct me to a tutorial where I can learn more about hydrological modelling? I am particularly interested in learning how to model flooding using data from gauging stations along ...
8
votes
3answers
554 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?
8
votes
2answers
170 views
How to link dataframes in ArcGIS or QGIS?
The below image shows a layout in ArcGIS 10.1 with four dataframes. Each dataframe is of the same geographic area, although they are different images. For example, the top left image is a 1989 DOQ, ...
8
votes
2answers
996 views
Running QGis from flash drive
How can I setup a portable QGis to run from a flash drive / USB-Stick?
In the userguide for QGis 1.7 Wroclaw there is only mentioned the option of "--configpath". But to me it is not clear how to deal ...
8
votes
5answers
2k views
A SQL console in QGIS
I know QGIS comes with its field calculator, which is not bad. It also comes with ftools which permits several operations on geometry and attributes. But we often need more control and I haven't seen ...
8
votes
1answer
603 views
Will there be an iOS version of QGIS?
I saw that QGIS now works on Android, any chance there will be an iOS version?
8
votes
2answers
2k views
QGIS vs ArcGIS (features)
I am learning to use QGIS and ArcGIS but I can not find the differences between them.
What are the differences between the capabilities of QGIS and ArcGIS?
8
votes
2answers
563 views
How to only show labels for an arbitrary selection of items?
I'm curious how others go about solving this problem: You've created a map for something with a large number of features that are labeled. The customer/client asks that you only show labels for X, Y ...
8
votes
2answers
2k views
Is it possible to create Thiessen polygons around nodes in QGIS?
Is it possible to create Thiessen polygons around nodes in QGIS? e.g. http://en.wikipedia.org/wiki/Voronoi_diagram
8
votes
2answers
130 views
Is there an automatic function in QGIS to package all shapefiles in a project for transferability?
In my project, I use a lot of geodata from different directories.
Now I want to give the QGIS project to a colleague (eg on a CD).
Is it possible to copy the shapes from different directories ...
8
votes
1answer
1k views
How to convert .shp into .gpx using QGIS?
I'm newbie using QGIS. I would like to convert .shp into .gpx. So, using Qgis, I open my shapefile and I tried to "save as" gpx but it gives an OGR error:
creation of field ObjectId failed (OGR ...
8
votes
3answers
3k views
Can QGIS read an ODBC connection?
I have a co-worker who manages a large MS Access database that contains X & Y fields for various locations he tracks. We have previously exported the data to CSV and used the QGIS Delimited Text ...
8
votes
2answers
128 views
QGIS Categorized Style: Rearranging values so that it doesn't go 57,58,59,6,60,61
I have a a column of data that I'm trying to display in the Categorized Style but when QGIS orders the values it ranks them, for example, 57, 58, 59, 6, 60, 61, 62....
Is there a way to rank them in ...
8
votes
2answers
622 views
8
votes
2answers
559 views
Converting ms-access database into easy to use spatial database
I've recently come into ownership of an MS-Access database (2007 accdb), which I want to be able to use in a GIS. I know a little bit about GIS (I've used QGIS and ArcGIS quite a bit) but very little ...
8
votes
1answer
244 views
How can I see the coordinate transformation parameters in QGIS?
How can I see (and edit if possible) the transformation method and parameters used by QGIS for "on-the-fly" transformation, and then for saving data in another CRS? Like in ArcGIS?
Here is the ...
8
votes
1answer
133 views
Why are some columns not recognized as numeric even though I have a CSVT?
I have problems importing a .csv file.
Some Values of the file are not supposed to be formated in text style, but in number style, thus i created an additional .csvt file like explained here.
Both ...
8
votes
4answers
588 views
How to identify duplicate attributes in a field?
I have a point shapefile with thousand of points. It has an ID code field that supposed to be unique. Every now and then the data entry clerk wrongly type the id creating duplicates.Right now I'm ...
8
votes
2answers
1k views
How to get FGDB support in GDAL 1.9 without compiling?
I was hoping that I could use the 'master' (nightly-build) version of QGIS to get fgdb support without compiliing (I'm not a developer and frankly have wasted days of productive time trying to get ...
8
votes
1answer
575 views
How to add features to a PostGIS layer using Quantum GIS?
I am using Quantum GIS and the PostGIS dbms. I am able to call the PostGIS layer into QGIS but i am unable to add feature to it. I am using the method of adding features to a Shapefile but still it is ...
8
votes
2answers
4k views
How to Add OSM Layer to QGIS
How can i add OSM layer in QGIS?
The help says there is an OSM plugin i can use. But i don't see it the list of plugins.
Or maybe there is a WMS URL for OSM i can use?
QGIS version ...
8
votes
3answers
573 views
Best way to manage large number of geoTiff rasters
I have around 2-3000 1-bit geoTiffs of size 11000x9400. Color 0 should be transparent, and QGis gets it wrong in the first place, so I used a .vrt file to set all the parameters in one single place.
...
8
votes
2answers
237 views
What to do with -3.4e+38 nodata values?
I am trying to process some bioclimatic raster files, such as can be downloaded from http://www.worldclim.org/current (bioclim set). They seem to have nodata values set to -3.4e+38 according to QGIS ...
8
votes
2answers
255 views
Options for a historic Web Map?
EDIT: I'm an intern at a small local history museum. We have a budget of $0.
Project overview:
I've got a bunch of old paper maps. When I say old, I mean 1800s and up. They've been scanned into ...
8
votes
2answers
230 views
Finding polygons without right angles
Now we are digitizing some buildings in specified area. The obligatory rule for this work - in most cases buildings should have right angles. We are using QGIS with CAD tools for this work. But ...
8
votes
2answers
2k views
How to perform Raster Reclassification in QGIS?
Is there a way to do reclassify a raster image to Qgis?
In Arcgis you can do that in Spatial analyst Tools-->Reclass-->Reclassify
Any ideas?
8
votes
1answer
640 views
What is the standard Mercator projection?
I'm using QGIS in order to re-project a shapefile I have into "Mercator" so that something like protoviz understands my co-ordinates. Protoviz tells me "Mercator" ...
8
votes
1answer
271 views
Is there a detailed description on the .qgs file structure somewhere?
Is there a detailed description on the .qgs file structure somewhere? I checked here: http://mrcc.com/qgis.dtd ("The requested URL /qgis.dtd was not found on this server.") and here- ...
8
votes
1answer
1k views
Dot Density Maps in QGIS?
Is there a 'friendly' way to create dot-density maps, where a polygon attribute data defines the number of dots (e.g. 1 dot = 100 ) using QGIS 1.7+? I say friendly because after a couple of hours ...
