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

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5
votes
1answer
151 views

How can I get the field index of the new layer in my script using Python?

I am trying to use layer.changeAttributeValue(fid, fieldIndex, value) to add values to a field in QGIS Basically, I'm creating a plugin which will, if a checkbox is ticked, create a new field, then ...
1
vote
2answers
441 views

How to add a new column in attribute table with attribute with indexes of another max-min ordered attribute field?

I've an attribute column named e.g. VALUE with different values I would like to make a column named e.g. ORDERsuch that the greatest value has the attribute 1 the second value 2 etc. etc. so order ...
3
votes
3answers
2k views

How to set all pixels with value <= 0 to “nodata” in DEM raster?

I have a DEM raster with pixel values between about 3000 and -0.0003. I need to set all pixel with a value of 0 and smaler (<=0) to "nodata" (for later raster calculations and to reduce the ...
0
votes
0answers
48 views

List attribute values ​​of selected points in the layer

I need to grab the fields in the layer of the selected points in the order they were selected by the user. My code: Connection to the database and display the map on the screen, everything ok: uri ...
3
votes
1answer
320 views

QGIS not interpreting Lambert Conformal Conic projection correctly

I'm a fairly new user of QGIS and I've run into an issue that I can't seem to solve on my own. I'm trying to work with the NRCan Atlas of Canada Waterbodies SHP file but I'm having an issues ...
0
votes
0answers
40 views

qgis - slope from DEM - errors due to projection and oversimplified 'z factor' [duplicate]

I'm trying to generate a slope raster from a DEM raster. It seems there is a pretty significant error due to the 'z-factor' option. I'm fairly new to this, but some other posts and responses ...
1
vote
1answer
147 views

Save input in plugin as pdf format file

I m trying to make QGIS plugin with plugin builder that compare 2 map scale with Input1 and Input2 as input scale and show recommendation after clicked recommendation button. I wrote my code like ...
0
votes
0answers
72 views

determine the catchment area from dem or hillshade [duplicate]

I want to determine the catchment area of river from hillside. Is there a plugin that I can use in qgis ?
1
vote
1answer
75 views

Is it possible to insert note to remember the info of a project?

Sometimes I need to open an old project, and mostly I remember how it works (i.e. the structure, the formatting and so on) but sometimes not. At other times I open a project composed by a colleague ...
0
votes
2answers
98 views

How to install maps2winbugs for QGIS?

I have got a maps2winbugs.dll file, but what should I do to install it into QGIS, sorry for the first time using this software, doesn't have any experients in C or R.
3
votes
1answer
172 views

How to fill the area bounded by lines in QGIS?

There are two types of area I want to fill color: The areas bounded by a line, such as a building The area bounded by different lines, such as the river I don't know how with QGIS. I only know how ...
4
votes
4answers
910 views

Matching GPS tracks

I'm looking for a proper way to process multiple GPS tracks (so time ordered list of lat/lon points) and match/classify that segments, that are covered by multiple tracks: So it's not about ...
1
vote
1answer
604 views

QGIS 2.0 Python API: Layer vector style loaded from file, marker symbology is respected, labels are not

Im loading a QgsVectorLayer and showing it on map. I load the style i prepared with desktop QGIS 2.0.1 using the layer.loadNamedStyles(path) function in the API and it seems to work, kind of, because ...
3
votes
2answers
202 views

Is there a function to select a region of a map for further processing with Python?

I would like to select a map's region in QGIS for further processing with python console. Ideally I would like to select the region with a mouse drag (like Gimp crop function) and then e.g. analyze ...
2
votes
2answers
487 views

How to create equidistant points in QGIS along a polygon?

I am looking for a solution to distribute with a python script equidistant points in QGIS along a polygon. I tried to use the following code example: ...
2
votes
2answers
64 views

Is there a way to create a new vector layer from a template?

I would like to be able to set up a template for a vector layer with a standard set of attributes rather the having to specify them time. Similar to SQL "CREATE TABLE blah LIKE foo" Is this ...
3
votes
1answer
130 views

Rasterlite db with multi table

When working with Spatialite DBs, I can store multiple tables in single DB. But now I want to store multiple raster tables on a single Rasterlite DB. I tried QGIS for conversion but it converts only ...
2
votes
0answers
190 views

How to merge points (bus stops) in QGIS manually or programmatically?

What I have: I have a large data-set containing links (bus routes( (>2000) and their respective nodes(bus-stops) (>6000). The data set I received from the local bus operator is very messy. It ...
1
vote
1answer
213 views

How to add a DEM Band to an existing 3-band TIFF file using QGIS?

I'm quite new in the GIS business and I do not figure out how to do the following thing: I have two geoTIFF Files, one is a 3+1 bands file (RGB+alpha), the second one is a DEM geoTIFF file containing ...
2
votes
1answer
146 views

graduated labels in QGIS

I've searched on Google but haven't found an answer. The QGIS Dufour GIS provide an enhanced vector-styling interface but is it also possible to graduate the labels like it is possible for the ...
0
votes
1answer
81 views

Create Area or Polygon based upon a Series of points

i have a large list of points that i would like to merge to create an Polygon based upon an attribute. Essentially an area that encompasses all points. x | y | attr ____________________ 1 | ...
7
votes
1answer
489 views

How to remove trailing zeros from QGIS Graduated Style Class labels?

I'm sure I've seen a solution to this before but now I can't find it. When using the graduated fill style in QGIS I get lots of trailing zeros in the labels. This makes my legends look messy in the ...
1
vote
2answers
4k views

How to export and import gps points from Garmin 62S and QGIS

I'm pretty new to using QGIS and I'm curious about how to import and export GPS points created in QGIS. I have QGIS 2.0.1 dufour on windows XP and a Garmin 62s. Any suggested walk throughs would be ...
2
votes
2answers
162 views

QGIS image export changes the map center and scale

I've been trying to export a few map layers using QGIS print composer. First, I loaded the layers and opened the composer using Project -> New Print Composer: Gave it a proper name: Added a ...
0
votes
0answers
29 views

How to turn this into a routable network that works with pgRouting? [duplicate]

I'm only asking again since I didn't get any answer and I'm still stuck here... I updated my last question with more info, but it wasn't answered. When I draw a line with snapping enabled and try to ...
1
vote
1answer
80 views

distance to polygon boundary

i have a layer of points, and a vector layer of county boundaries for the UK. I would like to be able to find the nearest county boundary to any given point and the distance using QGIS. any ideas? ...
1
vote
1answer
91 views

python scripts for accessing info from a postgresql database in case of a qgis application?

I am beginner and I need to know if I could access a postgresql database from python script made for a qgis application
1
vote
1answer
163 views

Help me to visualize polygon and point data [closed]

As part of pilot project, we have collected basic/rudimentary Household survey in one district. We have both Polygon and point data.Attributes of the database include, No of people living in the ...
1
vote
3answers
152 views

How to find area/multipolygon bounded by three other multipolygons?

Trying to get my head around PostGIS and QGIS...I'm trying to find the area (in white) bounded by three multipolygons (in purple) - refer to picture. Each multipolygon only touches the other two ...
2
votes
1answer
484 views

How to draw a simple bus network that works with pgRouting?

What I'm I doing wrong? I've created a new shape layer for lines, I've enabled snapping with 5 map units for that layer. When I draw a line between two of the stops I get a purple marker when I'm at ...
3
votes
1answer
257 views

How to apply a color gradient to a shapefile from QGIS console?

Anyone knows how to do a color gradient from the console to a shape file in Qgis (orin Python)? Like the image below.
0
votes
0answers
128 views

issue with QGIS Scale Level

I have different layers of shape files. I have imported all shape files into PostGIS. Now i want to show 3 layers Country, State & District with different scale/zoom level I tried to set scale ...
0
votes
2answers
95 views

How do I make shapefiles that I converted from .KML appear in QGIS?

I have created shapefiles from Google Earth but they do not show in QGIS, whereas in ArcGIS they do. I have made sure they are at the top of the layers, not transparent and also I have changed their ...
1
vote
1answer
50 views

not all polygons showing up in qgis 2.0

I am working with the block group shp files that I got from tiger 2010. When I bring in the shp files some of the block groups show up, but this is spotty. I have adjusted the CRS and still nothing. ...
2
votes
0answers
370 views

application of gis in geology [closed]

I am a student of geophysics and I am studying geographic information systems (ArcGIS) and we have been given a project. As I do not have much information about GIS capabilities can you please suggest ...
1
vote
0answers
18 views

How to move an existing point object to a coordinate? [duplicate]

Is there a simple way to move a point to an exact coordinate (do not intend to create a new point but move an existing point)? Something like, write the coordinates and move a selected point for ...
0
votes
0answers
389 views

Using Tile Mill and GeoJSON

I am trying to use Tile Mill and GeoJSON layers to have an image appear within a tooltip but it is not working properly. The process I go through to get the GeoJSON: 1) load .shp into QGIS 2) save ...
1
vote
1answer
357 views

How to get Google satellite images (via the plugin) to behave well in QGIS with a map created with a different CRS? [duplicate]

How to get Google satellite images (via the plugin) to behave well in QGIS with a map created with a difference CRS? I have a problem using the Google Image layer plug in - at some scales, it won’t ...
1
vote
1answer
156 views

determining what polygons intersect another layer

I am attempting to establish what spatial relationship exists (if any) between two layers. I have two layers - one is a road network with a buffer of 500m, and the other is a collection of polygons ...
0
votes
1answer
100 views

What expression returns data defined color from a color field eg: (30 50 40 10) using color_cmyk

Hi I have a geology plan with a base color field. I need to write an expression in the data defined color option using "color_cmyk" command. I can not seem to get the expression written correctly. The ...
3
votes
2answers
962 views

Calculating elevation profile of a trail?

What would be the best way to calculate an elevation profile of a trail remotely (without using altimeter/gps tracking your steps)? For example, to do it in the most rudimentary way you might take a ...
2
votes
2answers
364 views

How to Calculate Custom Zonal Statistics?

I have a vector polygon shapefile outlining counties for which I have a raster of nighttime-luminosity data. I've been able to compute Zonal Statistics in ArcGIS 10.0 using Zonal Statistics as Table ...
2
votes
2answers
445 views

QGIS DXF file projection match

I need to use this file on a map but I am not able to match the projection with the others I have, primarily data downloaded from OSM (city of Boston). I read many articles, I have repeatedly tried to ...
5
votes
2answers
223 views

Can someone clarify some details about freehand line tracing in QGIS?

I have read several tutorials and questions here on this site, but I have some lingering questions/doubts that I would like clarified. My project is tracing roadways from a 1926 map so that I can ...
1
vote
0answers
82 views

Megellan Meridian and QGIS GPS Tools help request

I am using QGIS 2.0.1 on Ubuntu 12.04. I have a Magellan Meridian GPS and I trying to use the GPS Tools plugin to download waypoints to a layer in QGIS. I have successfully used the Gebabbel ...
2
votes
1answer
325 views

Creating buffers that will not overlap in QGIS

I am dealing with a .shp with a number of points in it. The distances between points range from ~300m to 5km. I wish to create a 1 km buffer around each point with as little overlap as possible. Each ...
0
votes
2answers
163 views

How to add Excel-sheets with meter coordinates to QGIS?

I have an Excel-sheet where the coordinates are in meters. What is the most efficient way of inputting this file to QGIS? There are thousands of files to put so please recommend some straight-forward ...
2
votes
1answer
118 views

Bug when viewing data from SQL Server in QGIS

I'm having an issue with viewing data in QGIS 2 based on a spatial query in SQL Server 2008 R2. The data appears to load, polygons appear and I can add thematic shading based on data. However when I ...
1
vote
2answers
269 views

QGIS export ESRI Shapefile to SpatiaLite format issue

I am trying to export a shapefile of 3221 mixed POLYGON and MULTIPOLYGON geometry elements and every time, I get this same error: Does anyone have any idea what's going on? And no, this is not an ...
2
votes
0answers
78 views

Longest slope oriented to north?

I need a help with my homework. I have created digital elevation model from the shapefile. In QGis(Grass plugin) This is how far i can go. I have to find the longest slope oriented to North. I know ...