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

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3
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1answer
43 views

Why is QGIS rounding off manually added decimal attributes?

I am manually adding a decimal column in qgis and set the width and precision to one more than I actually need (Width: 5, Prec: 5)so the number comes out as 0.XXXXX, but when I save my eidts qgis is ...
4
votes
1answer
92 views

Identifying south facing mountain land, above an elevation, within a slope range, less than fixed distance from major roadways

This odd question comes from believing that such an analysis is plausible in a GIS system. Only, I don't how to accomplish the various discrete steps implied from the Title, nor where to get a topo ...
2
votes
1answer
77 views

QGIS Dissolve tool re-projects and rotates layer

I'm trying to use QGIS (2.6.1-Brighton) to aggregate polygons according to an ID attribute. I'm using the shapefile of school district polygons in Michigan found here: ...
2
votes
0answers
28 views

Trouble merging 2 rasters using qgis

I am trying to merge two rasters using the "merge" tool on Qgis 2.6. Qgis does complete the process, but the resulting image only shows one of the two rasters with the rest of the extent with really ...
2
votes
1answer
46 views

Calling canvas.saveAsImage from script in QGis -Qstring problem

I want to create a processing script that saves the QGIS MapCanvas exactly as it is seen on the screen and then Zip up the tifw and a created PRJ. The existing QgsMapCanvas.saveAsImage()-method does ...
2
votes
2answers
87 views

How to merge same long lat points with different data into a unique one?

I have a layer where there is more than 1 feature for a same object. Imagine i have a layer called signals. There can be up to 10 features in the same place (long/lat) for a unique signal but the ...
3
votes
1answer
33 views

Can QGIS 2.4 follow symbolic links to load data on Linux?

Q. Can QGIS 2.4 [Edit: NOT 2.8, brain-freeze] follow Linux soft links? I want to add a number of raster layers from a store of NED30m elevation data, and thought I'd do it by creating a collection ...
0
votes
1answer
87 views

Web map viewer for QGIS Server and PostGIS

I have succesfully installed and configured QGIS Server. I tried WMS and WFS via QGIS Desktop and it works perfectly. Now i am looking for a web map viewer to display (only read (WMS viewer i ...
2
votes
1answer
28 views

Colormap to grayscale map using QGIS?

I need to export color orthophoto map to gray scale geotiff file using free tools (like qgis) any idea? I tried qgis preview but this does not produce new geotiff file
2
votes
2answers
93 views

Adding new fields to shapefile alters appearance of borders in QGIS?

I am using QGIS 2.6.0-Brighton and I am trying to add a custom field to my layer made from a shapefile of Italian provinces; everything seems fine when I create a categorized views using region codes, ...
2
votes
1answer
48 views

Distance to nearest hub output not correct

In QGIS 2.6, I'm working with two point layers: center of the population per census tract and stores that accept food stamps. I'm using "distance to nearest hub" to calculate nearest food stamp outlet ...
1
vote
2answers
47 views

Georeferencing PNG with transparency via gdal produce “green pixels” in QGIS?

This is just intriguing while not blocking my way, but I wonder what is going on and would like to get feedbacks from more experienced users. 1) Given a trans.png file (1.1MB) looks good and ...
1
vote
2answers
37 views

why Input layers do not have the same grid extent in the processing, hydrological analysis?

I'm trying to generate the hydrological analysis using processing and I have already done some terrain processing using the DEM. In this moment, I'm working in he channel network but, when i assign ...
1
vote
1answer
62 views

Finding a vertical kilometer between 2 points with specified distance in QGIS

I'm new to GIS software. I want to find 2 points in selected area (lets say Czech Republic) with distance 5km or less and altitude difference 1000m or more. I know that I can use GMTED datasheet with ...
2
votes
1answer
71 views

QGIS equivalent for ArcMap join for purpose of distances from points to polygon?

It is relatively easy to calculate distances from points to a polygon in ArcMap by doing a join and selecting the option for creating a field containing the minimum distance information. i.e. it ...
1
vote
1answer
86 views

Qgis corrupted excel file, possibility to repair?

I had an excel file with several data which I imported into Qgis as a layer. For some reasons I had to change the data type of one coloum so I created a new one and imported data from the first ...
0
votes
0answers
21 views

ST_Touches Function in Iterative Process

Im a complete newbie to postgis. I have the following problem: Got two tables: "mp_power_lines_new" -> contains lines of an electricity grid "uw.new"-> contains polygons of all substations in this ...
3
votes
1answer
164 views

How to Install QGIS 2.6 plugins offline

"Due to various IT policies at my workplace, QGIS is installed on a machine (Window 7, 64bits and QGIS 2.6) that is not connected to the internet. I wish to install a couple of QGIS plugins on this ...
1
vote
0answers
24 views

Object Inspector Button not enabled in python console of qgis

I am using QGIS2.6 version. I loaded an existing py file in a editor. Though I added a codes in the editor, the object inspector button was not enabled. Please help me in figuring out what would be ...
3
votes
1answer
55 views

Shapefiles not showing in OpenLayers using QGIS export to OpenLayers 3 plugin?

I am new to GISs in general and I am working with QGIS to generate layers to be shown on OSM using OpenLayers. My problem is the following: I have multiple layers in a QGIS project and I want to ...
3
votes
0answers
41 views

PyQGIS: Trying to export layer to shapefile

I´m using python in QGIS 2.2 and struggling with an error trying this: # create layer from text _vlayer = QgsVectorLayer(_ur1, "raw", "delimitedtext") works fine but: # export layer to shape ...
3
votes
1answer
131 views

Transform shapefile to WGS:84 (EPSG: 4326) in Qgis

I am struggeling with an enoying problem here. I received several shapefiles from an colleague that he told me is in WGS:84. If I look at the metadata in Qgis it tells me the following: In layer ...
3
votes
1answer
87 views

How to create a clickable hyperlink in a QGIS form?

I have a hyperlink field in my table. I wish I could go to those addresses without using actions. I want to go directly from the form by clicking on them as happens in a hyperlink. It is possible? ...
2
votes
0answers
97 views

Openlayer georeference location is not correct [closed]

I am running QGIS 2.2, Windows 8.1. I have openlayers plugin installed. None of the openlayer sources display in the correct location. For example, Google hybrid displays multiple worlds tiled ...
1
vote
1answer
32 views

How to use field calculator in QGIS to calculate new coordinates, and use that new columm to geolocate a layer's points

In a separate question, at How to shift a CRS by an observed offset, I asked about shifting a CRS to align the problems aligning data points with a satellite image obtained from OpenLayers. (They ...
2
votes
1answer
35 views

Why can't I add a Spatialite table with clip results in QGIS?

I have 2 layers and I want to make a clip of layer 1 with layer 2 in SpatiaLite (I'm using the DB Manager within QGIS). That's the code I'm using: create table clipped_lines as select * from lines, ...
1
vote
1answer
60 views

What is the “Auto Open Form” checkbox used for?

Windows 7 QGIS 2.6 - 64 bit Feature - Identify Results Could someone help me understand what is "Auto Open Form" checkbox used for.
4
votes
1answer
97 views

Comparing floor and roof areas using QGIS?

I am pretty new in this GIS topic and I would really appreciate if someone can help me with this problem. I am doing a research for university that shall show the available roof area for ...
1
vote
0answers
44 views

Finding census block with highest pop. value within the census tract

In QGIS, I'm trying to plot a centroid of only the census block with the highest population within each census tract. So there should only be one point per tract- that of the block with the greatest ...
1
vote
0answers
60 views

How to determine Affine Transformation Parameters? [duplicate]

I try to use the qgsAffine plugin to do the transformation. But no idea in its usage. Anyone can post an example. Many thanks!! How to find the transformation parameters? I found some posts suggest ...
1
vote
1answer
50 views

how to generate NDVI with multi channel images?

I have a 6 channel proprietary camera and I need to create a NDVI map. I created a map from each band, so now I have 6 files each one on a different band width. How can I proceed now? I am using QGIS ...
2
votes
1answer
65 views

Finding and using data on population density files

I'm attempting to replicate this map for the state of Nevada in QGIS: source: http://www.bostonfed.org/commdev/c&b/2014/spring/map-distance-to-closest-snap-outlet.htm (A SNAP outlet is just a ...
1
vote
0answers
37 views

how to automatically update column based on the second layer, trigger, postgreSQL

I am newbie in postgreSQL. I have 2 tables, observation and landcover, i want to create a trigger which would allowed to update the column observation.land based on the spatial information according ...
1
vote
1answer
32 views

Route and distance measuring

I'm looking for a plugin that can make a route from given GPS points and then calculate the distance of this route. I'm going to create GPS points and import it to Qgis as a GPX file. I know I can ...
2
votes
0answers
21 views

Help getting a Mathematical Representation within a Layer's Attribute Table

I'v been playing around with Vector Coding and was wondering if there was any Plugins out there that might let me represent Vectors within a layer as it's Mathematic attributes in the Layer's ...
1
vote
0answers
63 views

How to create a floor plan KML file from a DXF in QGIS? [duplicate]

I import a building floor plan from DXF format to QGIS. When I export it to KML format and then import it in Google Earth, how can I put the floor plan to my desire building location? MY CRS is WSG84 ...
2
votes
1answer
79 views

What am I doing wrong with QGIS v.clean?

I thought I understood how the GRASS v.clean tool worked in QGIS (in 2.6.1 Brighton) but I keep getting unexpected results and errors with a polygon ShapeFile. I've run the QGIS TopologyChecker with ...
2
votes
2answers
83 views

QComboBox nested within a Qmenu?

Is it possible to nest a QComboBox inside of a Qmenu within QGIS? Below is my current code and an associated screenshot with the unexpected results. (orange = current incorrect placement, green = ...
1
vote
0answers
51 views

Assessing Flood Hazard Risk Zones using DEM

My Question: What is the best effective way to quickly estimate flood hazard risk areas using DEM data? Ideally I am looking for guidance to move forward and perform this process over large areas ...
1
vote
0answers
20 views

Syntax to use when entering geographic data into geography columns via SQLSERVER Management Studio

I am starting to learn about spatially aware databases. I have QGIS 2.61 and SQLserver express 2012. I can set up a table using the SQL Server Management studio GUI and insert a geography column. ...
0
votes
0answers
90 views

How to fix “Unable to load GdalTools plugin. The required ”osgeo [python-gdal]“ module is missing.”

When I start QGIS, it display error message: Unable to load GdalTools plugin. The required "osgeo [python-gdal]" module is missing. Install it and try again. Couldn't load plugin 'processing' from ...
1
vote
1answer
25 views

QGIS plugin select and edit features performance issues

I wrote a plugin for selecting and instant updating the value of the selected feature in the attribute table. I tested with a big shapefile and to select and edit 5 features takes ~5 seconds. Which ...
2
votes
0answers
30 views

How to digitize in stream mode in QGIS, using a tablet?

How to digitize in stream mode in Qgis, using a wacom cintiq tablet? freehand it's no use. i need something like MNDR stream digitizing extension for arcview 3.x, which allows continuous tracing, ...
1
vote
1answer
39 views

Adding shapefile layers in QGIS causes previous layers to disappear

This is my first time having such trouble, but I'm only a casual user. I have a base raster layer of the school I work for and I've been adding vector shapefiles on top of that in separate ...
1
vote
1answer
49 views

How to split a text attribute by characters in QGIS 2.6.0

Is it possible to make a new column, for example named "Test" and store the first part of the column "Name" split by -? See below how it should look like:
-1
votes
2answers
67 views

File or personal database in qgis?

is there any database ? I use ArcMap with file geodatabase. But now, i have make project in qgis and i dont know, how to create database.
2
votes
1answer
48 views

QGIS has an automatic way of finding the LS factor?

I wonder if is possible to calculate LS (soil erosion) factor automatically in QGIS? Or at least a way to calculate the length slope?
3
votes
3answers
551 views

QGIS OpenLayers 3 Google Maps not zooming

Google Satellite will not zoom. Although the scale changes as I zoom, as the map is re-rendered, it zooms out to its maximum extent every time. This first happened in the latter part of November ...
1
vote
0answers
27 views

Projection problems when importing .kml from Google Earth to QGIS

I want to open several points that I exported from Google Earth as a .kml in QGIS for further use. I can import the data and the points are displayed but something must be wrong with the projection as ...
1
vote
1answer
53 views

What is a memory vector layer in QGIS?

What is a memory vector layer and how does it relate to the vector layer? Background info: I have a volunteer working with my organization, because of financial reasons we have him using QGIS. He ...