Questions tagged [qgis]

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

Filter by
Sorted by
Tagged with
3
votes
3answers
4k views

Are there any geocoding plugins for QGIS that interpolate along linear features instead of querying web services?

I am curious if there are any tools for QGIS to facilitate geocoding tabular data using a local linear features layer (ie, a street map with street name and address ranges - similar to geocoding in ...
2
votes
2answers
1k views

Graduated Symbol classification not working with a decimal range [closed]

I am classifying an .adf wind resource map which I vectorised using the Polygonise tool (which worked very well). I have classified the data using the Graduated symbol renderer using Natural Breaks (...
2
votes
2answers
527 views

Is it possible to attain a classified raster with several classes in just one QGIS raster calculator operation?

I'm using qgis' raster calculator and wanted to make a new raster (oraster) from the values of an input raster (iraster). something like: if iraster>2 then oraster=1; if iraster >4 then oraster=2; ...
1
vote
0answers
367 views

Manifold 'Link drawing to query' - can I do this in QGIS?

Manifold GIS allows the creation of dynamic drawings linked to queries. Unfortunately I do not have access to Manifold as my employer refuses to pay for it, so am currently investigating alternatives....
4
votes
1answer
930 views

Where to activate “Vector” Menu?

I am a QGIS newbie trying to work through Lex Berman's QGIS tutorial. I'm stuck in the "join" unit, because I do not see a Vector menu on my menu bar. The screen shots show that there should be a ...
2
votes
0answers
182 views

Are there Plugin Compatibility Issues between QGIS 1.6.0 and 1.7.4?

I've been working on a QGIS plugin on Quantum GIS 1.6.0 Copiapo with Python 2.5 that calculates additional values for eachf feature of a vector layer and adds them to the .dbf. We've just upgraded to ...
2
votes
1answer
196 views

How to digitize from a map with additional detail views?

I have a map with a river that includes islands within it. Some islands have a blown up version (detail views) outside of the river showing land ownership details. I would like to make polygons (...
14
votes
2answers
25k views

How to copy features from a vector layer to another vector layer with only correspondent attributes in QGIS

I have two vector layers: A first one with all cadastral parcels of a region. This layer has several attributes, it's only the geometry and 3 of the attributes I'm intrested in. My second layer is a ...
3
votes
1answer
2k views

How to show labels depending on the zoom scale and save it forever in one project?

I have got a problem in showing labels for a polygon layer : When I select "Show labels" in the layer's properties, then I select that I want to use the scaling to show or not my labels and I ...
4
votes
1answer
7k views

How to modifiy how selection highlights are displayed? [closed]

I have got a layer of points that are showed with a little symbol. When I select one, a red square comes around it. The problem is that these points are inside other layers (polygons) and some of them ...
8
votes
1answer
23k views

How to display places names when using Quantum GIS and shapefiles?

I am new to the world of geo systems. What I would like to do is displaying some information on a map for given regions. I downloaded shape files from cloud made web site and load layers using ...
12
votes
4answers
17k views

How to import qgis.core to Python app?

I'm new to Python. I want to create GIS app with Python using QGIS library on Window 7 64 bit. The way I do: install QGIS 1.7.0 I set PYTHONPATH=D:\Program Files (x86)\Quantum GIS Wroclaw\apps\qgis\...
5
votes
1answer
233 views

How to keep Table Order in Identify Results?

Is there a way to keep the default table order when using the "Identify Feature" tool. I see that you can sort the "identify results" by table column name or value. I don't want the data in this view ...
3
votes
3answers
2k views

How to extract the US from a North America Shapefile?

I have a north america shapefile, downloaded from ftp://ftp.epa.gov/wed/ecoregions/cec_na/NA_CEC_Eco_Level2.zip How can I get a new shapefile from this showing only us? Is there a way doing this in ...
4
votes
3answers
2k views

How to add a raster legend with min/max values in QGIS 1.6?

I calculated/made NDVI with landsat data using ERDAS. Results of NDVI is in black and white map but I need it in colour to present the scale for NDVI with value of pixels in Map Composition. How to ...
1
vote
1answer
1k views

Why does qgis become unresponsive when adding a .sid raster layer?

Can someone provide insight into why qgis becomes unresponsive when i try to add a raster layer? Specifically a .sid raster from NAIP imagery. I can no longer add these raster layers to projects, even ...
1
vote
1answer
997 views

Why does intersect not calculate polygon areas?

this is strange: I intersected 2 shape-files and the resulting shape does not contain the Shape_Area and Shape_Length of the intersected polygons. Instead the field Shape_Area contains the polygon-...
2
votes
2answers
3k views

How to control line width in legend in QGIS?

I have a map in which I am defining the sizes of various features in map units. When I come to generate a pdf of the map, using the Print Composer, the map itself is fine, but when I include a legend ...
8
votes
1answer
827 views

How to get rpy2 for QGIS on OSX?

I am a new QGIS user, have installed QGIS on a Mac running Snow Leopard OSX 10.6.8 following all the instructions. QGIS seems to work well for everything other than when I boot up I get the message "...
2
votes
2answers
8k views

How to export a raster layer for external processing?

Is there a way to export all values from a raster to for example a cvs or other textfile or dbf or xls and later import (changed) values from that file back into the raster? For vector-files this is ...
7
votes
3answers
14k views

How to exclude missing values from raster layer?

In my raster layers the value -999 means "missing". Those points completely mess up any colormap in qgis because qgis treats them as normal values and includes them in the classification. I would ...
2
votes
0answers
677 views

Trouble with Python plugins on QGIS [closed]

This question has been bugging me for a while now, and I still haven't managed to solve it, so I'm giving it another go, hopefully someone may help me out. I've been having problems loading several ...
1
vote
3answers
4k views

How to extract a rectangle corner coordinate in Python script

I want to extract a rectangle corner coordinates of a shapefile in Python script... please suggest me a solution.
8
votes
6answers
9k views

Creating multiple buffers using QGIS?

I'm new to QGIS and have no programming skills. Is there an easy/uncomplicated way to create multiple buffers around a line feature?
0
votes
1answer
1k views

GRASS and QGIS- “ not recognized…format” but it worked before

Prologue: I used my Ubuntu file viewing GUI to move data files around and "clean house" a bit. I started a new GRASS session and tried to add NED elevation rasters which I have successfully added ...
28
votes
4answers
81k views

Converting vector layer to raster using QGIS?

In qgis in the raster menu there is an item "convert vector to raster". This behaves strangely - I do not understand how it is supposed to work. I can select a vector file, an attribute and an ...
17
votes
7answers
25k views

Georeferencing DXF using QGIS? [duplicate]

I have got myself a dxf which is built with units in the wrong scale. How do I upscale that in QGIS? Note it does open in QGIS, just in the wrong map units and location.
1
vote
1answer
516 views

How to create one shapefile from multiple rasters?

Ok, I have about ten maps that connect along their edges to each other linking rivers and properties. When I link them all in Inkscape I end up with a large file that won't save (and a smaller one ...
4
votes
2answers
2k views

Is it possible to automatically set CRS of Rasters from PRJ file?

I am trying to learn my colleagues to display measured data (ASCII) in maps relatively easily. I can prepare project, color and symbology style for the point layer and background map. I also found ...
1
vote
2answers
1k views

Where to choose a shapefile for appending?

I want to append several shapefiles in QGIS. The ftools 0.6.1 add-on is installed. But under Vektor>Datenmanagement-Werkzeuge>Shapedateien zu einer zusammenführen (=append shapefiles) is only the ...
10
votes
2answers
6k views

Why can't I edit KML/GML layers?

Newbie here confused by my first experience in QGIS I have a handful of lines defining a bike route. Originally they were saved in a .gml file and later translated into .kml so they could be viewed ...
0
votes
2answers
498 views

Why does only one of three elevation rasters display correctly?

I downloaded a selected sub-set of the USGS National Elevation Data (NED) using their online GUI. This download came in the form of three files. The names of the files are 61471006, 61471006_2, and ...
3
votes
3answers
2k views

How to generate heatmaps with QGIS1.9 plugin automatically?

I created a few heatmaps with the new plugin in QGIS 1.9, but now I would like to generate a lot of them automatically. How should I do? I created a few of them by hand, but I should first import the ...
1
vote
1answer
371 views

Looking for help identifying projections and reprojecting

I'm still struggling with projections in QGIS. The "Vogelschutzgebiete" reprojection worked. But these ones seem to be tougher: www.projektidee.org/images/extern/Gemeinden.zip as well as the same ...
0
votes
1answer
1k views

How to work with OS map files from Digimap?

I am trying to add map tiles as raster files in QGIS but when I add them they all appear on top of each other. I did this once before and everything was ok but I am now unable to find how to get the ...
9
votes
1answer
4k views

How to export multiple Shapefiles to one KML file in QGIS?

As the title says, is it possible to export multiple Shapefiles to one single KML in QGIS (Similar to "Map to KML" in ArcMAP)?
3
votes
2answers
4k views

Is there a browser/management view in QGIS?

Is there a browser/management view in QGIS 1.8 so that I can manipulate shapefiles and others (such as geo tiffs, etc.) like in ArcCatalog? Maybe a plugin? Right now I have to use my system's file ...
5
votes
1answer
2k views

Is QGIS suitable for noise modelling?

I've never used any type of GIS software before so I'm trying to find out if it is suitable for what I'm trying to do: I've written a c++ program which estimates ground level noise from a distant ...
7
votes
3answers
12k views

Combining information from raster and vector layers in QGIS?

in QGIS I have 1 raster-layer (elevation) and 1 vector-layer (administrative units). Now I would like to be able to query one of the administrative units and see the mean and min/max of the elevation ...
1
vote
1answer
173 views

I would like to show points moving on a map by date

I would like to create a map where I can see points moving. I have table of points for example with a date column, A 01/01/2012 B 02/01/2012 C 03/01/2012 D 04/01/2012 E 05/01/2012 F 06/01/2012 I ...
10
votes
0answers
39k views

How to add Lat/long columns to a point layer which is not in WGS84? [duplicate]

I need to extract the Lat/long coordinates of the centroids of districts. My QGIS project SCR and the different layers have all been set on "WGS 84 / UTM zone 18N". I've created the centroids using ...
5
votes
2answers
648 views

How to Intersect a layer with custom CRS with NED data?

I am trying to create a map with a layer of county tax assessor property parcels plus NED elevation data. The projection of the tax assessor layer is a weirdo -- looks like user-created by the ...
5
votes
2answers
1k views

Is it possible to generate a vector polygon from a polygon on a raster image?

I have a raster map which I have extracted from a government report providing flood extent return frequencies. I want to 'snatch' these flood extent polygons (i.e. convert to vector) and I was ...
17
votes
1answer
9k views

How do I build a custom form for entering attributes in QGIS

I've done this many times in ArcGIS and ArcPad but I don't even know where to start building a custom form for data entry in QGIS. I would like to do this for field operations--QGIS would make a good ...
2
votes
1answer
354 views

Heat Map to find 10 restaurants, 10 retail, and 10 stores open after 6pm within 3 linear blocks

I would like to find where in the City there is a combination of 10 restaurants, 10 retail, and 10 stores open after 6pm within 3 linear blocks. What is the best way to do this? What data would I need ...
21
votes
4answers
22k views

Layer stacking rasters in QGIS?

I have some multi-spectral data, where the individual bands are separate Raster files. How do I layer stack these rasters so that I get one raster with 3 bands instead of 3 different rasters? This ...
6
votes
3answers
3k views

Any issues going back-and-forth between QGIS and ArcGIS Desktop software? [closed]

I have very simple work tasks at the office (digitizing) that I would like to be able to work on at home because we are exceptionally busy. I don't want to spend thousands of dollars purchasing ...
31
votes
2answers
45k views

How to access file geodatabase in Qgis? [duplicate]

How does one access data from an Esri file geodatabase in Quantum GIS? I've seen snippets of conversation that indicate it's possible with qgis 1.7+ and gdal 1.9+ but no clear recipe. I recognize ...
2
votes
1answer
3k views

Do QGIS Field Calculator xat(n) and yat(n) functions work in version 1.7.x?

I'm trying to use the xat(n) and yat(n) in the Field Calculator but can't get them to work. Does anybody have an example how to use them? I need the start and end coordinates for line segments, does ...
3
votes
2answers
2k views

How to handle AutoCAD map to QGIS workflow?

I'm looking for some assistance and like many here, I am pretty much a GIS novice. I'm working on a project to map our local cemetery (about 40 acres), locating sections, lots, and graves, etc. I ...

1
644 645
646
647 648
654