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

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2
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0answers
82 views

select by location

When performing an overlay or intersect I would like to know if there is a way to ignore selection when intersection or overlay is less than a certain percentage of area or less than a certain number ...
0
votes
1answer
278 views

How to properly add a Python Module to a Plugin?

I've been trying to use a module that is installed in my local version of python, but whenever I open the plugin itself, it does not manage to locate said module. The module in this case is Noise ...
3
votes
2answers
289 views

Adding a GIS feature to existing database entry with QGIS

I've built a database with postgreSQL with tables, which include geometry columns. When I add some data to my non-geometry columns, I can see them in QGIS when I connect to my database using postgis. ...
0
votes
0answers
75 views

What vector file type yields the greatest detail with the Heat Map plugin?

I'm using .shp files built from .csv files and having quirky results. Perhaps there is a better way to begin. The heat map appears to be accurately describing the data but calculates a huge area in ...
9
votes
2answers
379 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 ...
1
vote
0answers
265 views

Can I create a custom Shapefile for SAS with QGIS?

Okay - I am in the process of configuring GIS within our organisation and am waiting for QGIS to be installed. My aim is to use QGIS to compile a custom shapefile of the business regions used by our ...
2
votes
1answer
2k views

How does Quantum Gis work with Arcgis .xml files?

I'm not familiar to quantum gis, so can anyone explain if it is possible to import/export xml files in quantum gis? If it is possible, how can I do that? I exported some . xml recordset and workspace ...
1
vote
0answers
174 views

QGIS plugin 'sextante' not loading after upgrading to Mac OS X 10.8

Any known issue with sexante and Mac OS X 10.8? After updating from 10.7 and even after reinstalling GDAL sexante is still not working...
5
votes
3answers
702 views

How to drape a simple jpeg image over dem of some area?

How can we drape a simple jpeg image which doesnot have any geo referencing information over the digital elevation model in order to visualize it in 3D in QGIS?
0
votes
2answers
250 views

QGIS 1.8 crashes when exporting from print composer to image on Windows 7

My question is similar to QGIS Crashes when writing to PDF. Today, when I try to export to image, QGIS crashes. I've tried opening a new composer to no avail. This is the problem signature: Problem ...
1
vote
0answers
105 views

'File is too big' error when uploading QGIS Plugin

I have written a simple QGIS plugin which zooms the map canvas to a user specified UK postcode. I would like to share the plugin but the csv file, which contains stripped down OS Code-Point open data ...
2
votes
1answer
362 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
2answers
876 views

Can't open Spatialite db from openstreetmap in Quantum GIS

I am new to QGIS, OpenStreetmap and Spatialite. I'm trying to get the (OSM) map data into a (SQLite) compact form I can eventually use for realtime reverse geocoding in a vehicle. Quantum is just for ...
3
votes
1answer
621 views

Can the units of the measure tool in QGIS be changed?

All, I'm trying to do some error-checking with some rasters I'm creating, and want to measure line distances on the map in feet, rather than meters - which is what the measure line tool seems to be ...
2
votes
2answers
315 views

Selecting lines occupying identical positions in MapInfo or QGIS

I have two shapefiles from a client, one is their entire network (complete with unique IDs) and another a selection I need. However the selection file does not have unique IDs but the entire one does. ...
1
vote
0answers
82 views

mapCanvas.saveAsImage not functioning as expected in QGIS 1.8

I have a plugin for exporting maps as PNG images. I believe this code was working correctly within 1.6 (but I cannot guarantee I haven't made another change that would have broken it there, too). ...
3
votes
2answers
955 views

How to create a multipart polygon?

I have two polygons that consist of two separate polygons/lines in QGIS). How can I make this into a multipart polygon, which consists of 1 line in QGIS?
1
vote
1answer
728 views

Illustrator to QGIS workflow for vectors

I vectorized a map in Illustrator and would like to import it to QGIS now. I know I must use DXF for that purpose but when I convert the DXF to SHP with the QGIS plugin it is not georeferenced which ...
2
votes
2answers
138 views

How do I stop null values from being assigned extreme color values?

I have a raster surface that I kriged in Surfer and imported to Grass GIS but when I view it in QGIS, the null values outside of the interpolated surface take an extreme value and wash out the ...
1
vote
2answers
140 views

Problems with Combining Layers in QGIS

I am trying to add the political boundaries baselayer from http://www.cec.org/Page.asp?PageID=924&ContentID=2336 and then on top add points where I gathered coordinates from Google Earth (using a ...
3
votes
1answer
497 views

How do I use the GRASS command line tools within QGIS?

How do I use the GRASS command line tools within QGIS? I use the QRASS plugin to open the mapset, and then I open the GRASS tools window. I click on 'GRASS shell' under modules and it brings up a ...
2
votes
1answer
101 views

What is No Data Value?

I'm looking at the transparency window of the layer properties of my "Heat map". How does the No Data Value effect a raster layer. I'm assuming an initial setting of -9999 sets it out of the way, so ...
2
votes
0answers
225 views

Can Nearest Neighbor Analysis help determine values for a Heat Map?

Given the below parameters (from Nearest Neighbor Analysis): A) Is there a definite range my Radius value should be within? B) Are there definite values my cell size should be near? C) Is there a ...
1
vote
1answer
120 views

How to use QgsVertexMarker in a python plugin?

I am trying to display a vertex marker for a QGIS python plugin I am writing. I am getting a the following error... 'NameError: global name 'QgsVertexMarker' is not defined' canv = ...
13
votes
1answer
688 views

How to setup QGIS Master and Stable in parallel on one Linux system?

I mainly use the QGis Master (nightly build) for my Debian Linux and I'm quite happy with it. But for educational and demonstration purposes, I now have to work with the Stable(1.8) version. How can ...
2
votes
2answers
1k views

Importing Lat/Long coordinates as CSV file & only displaying single point in QGIS

I am using QGIS and trying to import Lat/Long coordinates as delimited text layer. All points show up in my attribute table, however, only one point is displayed on the map? Any ideas?
1
vote
2answers
135 views

Why does my 113th Congress Shapefile match up with the wrong districts across the country?

I downloaded a Shapefile from the Census on the 113th congress broken down by district nationally: http://www2.census.gov/geo/tiger/TIGERrd13_st/nation/tl_rd13_us_cd113.zip Within the .dbf file, ...
6
votes
1answer
2k views

Best Way to Handle Many Raster Files in QGIS?

I have a project with a large number of raster files, but it is becoming very slow. I wonder which is the best way to handle all this. I'm simply georeferencing these files creating .wld file (geoTiff ...
1
vote
2answers
104 views

Missing GPS Tools button

Following the guidance at, http://docs.qgis.org/html/en/docs/user_manual/working_with_gps/plugins_gps.html I checked my Plugins Manager and verified that GPS Tools is enabled. However, unlike what ...
2
votes
1answer
775 views

how to connect points to create a polygon boundary in QGIS

I have 31 points in a shapefile, which delimit a field (it's an irregular shape). I want to connect those points so they create the boundary of a polygon. Does anybody know a kind of "connect the ...
3
votes
2answers
764 views

How to calculate the area of rasters in QGIS?

I have been working with some rasters and would like to know how to calculate the area occupied by one element of a raster in Qgis.
2
votes
2answers
1k views

Is it possible to use WMTS in QGIS?

Is it possible to use WMTS e.g. by http://data.wien.gv.at in QGIS? ich möchte gerne daten der stadt wien als WMTS-Layer in qgis hinzuladen. ist das überhaupt möglich? ich bin kein profi und bitte ...
1
vote
1answer
406 views

Creating routable network table in PostGIS

I am trying to create the routable network table, as per http://underdark.wordpress.com/2011/02/07/a-beginners-guide-to-pgrouting/. Everytime I do it in PostGIS extension, QGIS crashes. The area is no ...
1
vote
1answer
83 views

Scaling location points proportionately

I'm trying to get QGIS (1.8) to scale the point markers for each town in a district proportionately to the size of their population (i.e. bigger population = bigger circle). I can get them to vary by ...
5
votes
1answer
137 views

What suit of components do I need to get installed to start with QGIS?

I have a requirement for a GIS product and following advice from firends and colleagues have decided that Quantum GIS seems suitable for what I need. I have input a request to our IT section to ...
1
vote
2answers
630 views

Are there any work-arounds for WMS width and height limit when printing?

I get the following error when trying to export in QGIS to PDF: "Some WMS servers (e.g. UMN mapserver) have a limit for the WIDTH and HEIGHT parameter. Printing layers from such servers may exceed ...
1
vote
2answers
669 views

Error adding a delimited text layer in QGIS [closed]

I'm a GIS beginner here. I'm trying to add a delimited text layer in QGIS. The plug-in is okay. I have created a table in Excel, saved as CSV file, imported the file with QGIS, selected the delimiters ...
1
vote
1answer
407 views

What are Bands, Dimensions, and Histograms in QGIS?

First; I can see a band as synonymous with a channel in an image editing program like GIMP, is this correct? If so then bands play the role of color mixing and masking. Are there any other ...
1
vote
0answers
30 views

Why does my QGIS want to create so many icons? [duplicate]

Not sure on protocol here--I asked this previously, but the responses petered out-- Every time I open a Print Composer, a box comes up, and text flashes by saying, "Creating icon for file [various ...
2
votes
1answer
193 views

Sum line length with clip intersect? [closed]

SELECT sum(st_length(st_intersection(POLY.geom, LINE.geom))) AS sum_line_length... Is this function OK to calculate the sum of lines length? Wonder if it do the clip line where one line go from one ...
1
vote
1answer
281 views

Cannot install TimeManager 0.7: no module named six

I was able to extract and copy dateutil to C:\OSGeo4W\apps\qgis\python\dateutil and the error saying that dateutil wasn't found disappeared. But now I am getting the error no module named six. Tried ...
2
votes
1answer
342 views

QGIS rounds up the coordinates to six decimals when saving layer changes

I have the problem that when I create a new point (in a point layer) or a new line (in a line layer of course) and I save the changes to the layer (so NOT the project save) then QGIS rounds up the ...
3
votes
1answer
67 views

What defines a Class in the Heat map plugin?

What defines a Class in the Heat map plugin? As in: "Black holes like that are usually caused by raster values exceeding the range of the color ramp. Try adding another class with a higher associated ...
2
votes
1answer
50 views

How to make a certain attribute Toggelable? [duplicate]

I have imported data from an excel spreadsheet containing lat,long coordinates associated with other attributes such as current operator of each point (well). I imported as a tab delimited file, then ...
10
votes
3answers
2k views

How to snap lines to points automatically?

I have two vector shapefiles: One file is points representing manholes and the other is a polyline file representing pipes leading to and from the manholes. I need to snap the lines within a ...
3
votes
1answer
960 views

How to convert jpg file to shapefile? [duplicate]

I am developing a GIS application like this: By now my steps are: I have got a jpg file, 5040 x 8179 dimension. In this map, the roads, rivers, towns etc. are marked. I am using .Net to develop ...
1
vote
1answer
329 views

Find closest point from origin in QGIS and display measure line in composer

I have a location point. there are several constraints areas surrounding the point. Is there a way to calculate the closest point of this constraint from my point and to display the distances as a ...
6
votes
2answers
633 views

How to implement multivariate hex bins?

I have two point datasets that I am analyzing and I wanted to implement a multivariate hexbin approach for displaying this data. I have managed to cobble together an approach using QGIS SVG symbols ...
3
votes
1answer
416 views

QGIS Print Composer Export problems

When I attempt to “Export as PDF” a Print Composer image, it hangs up until I press cntrl/alt/del, whereupon I learn that QGIS is not responding and needs to be closed. I’ve tried this as jpg, jpeg, ...
0
votes
1answer
81 views

gdal_contour creates an empty shapefile

I am running: gdal_contour -a elev hazard_interp4.asc haz_ak_contour_4_10 -i 10 the hazard_interp4.asc file has values in band 1 (singel band gray). With the above command, I get a shapefile that ...