Questions tagged [qgis]

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

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3
votes
1answer
8k views

Import MySQL Spatial vector layer in QGIS

I have a spatial table called 'places' in MySQL, with a spatial column 'pt' (point). I tried to import it in QGIS and no points appear. I created a view 'places_as_text' which reproduces the table but ...
0
votes
1answer
144 views

how to overlay GPX data on rasters in QGIS [duplicate]

Possible Duplicate: Overlaying GPX data on rasters in QGIS When both layers are displayed in QGIS, they are not even visible in the same display. The coordinates displayed for each are wildly ...
2
votes
1answer
747 views

How do you change the Window Icons in QGIS 1.7

I am a beginner to QGIS 1.7, and I want to change the icon files in QGIS, (wherever we see the 'Q' icon I have to change that). I tried and I got success in the case of the mainWindow, and also ...
6
votes
1answer
1k views

Creating color tables for floating point raster maps in GDAL?

I've got a script that dumps a floating point raster that I'd like to automatically color. Currently I load this raster in ArcGIS Desktop or QGIS and manually create a color table every time I re-run ...
5
votes
1answer
1k views

Distance between points and polygons in QGIS / PostGIS

I need to work out the distance between a table of polygons and a table of points. The table of polygons has different site boundaries, and the point table has points relating to each of the site ...
0
votes
1answer
2k views

QGIS and MapInfo Projections - EPSG 27700 (British National Grid)

I have some data in a PostGIS table with the projection EPSG 27700. If I export this data from QGIS (v1.8) to MapInfo TAB / MIF when I open the data in MapInfo it has a shift on it. Does anyone know ...
6
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1answer
7k views

Add or Import Metadata to a shapefile

Is there a way to add metadata to a shapefile in QGIS? I have the shapefile and an XML metadata file and I want to import in shapefile.
10
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4answers
13k views

How to fix QGIS error "Entry Point could not be located"?

Today, after returning from vacations, I started my QGIS 1.7 and got this terrible message: Help, anyone?
5
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2answers
2k views

Quickly create contour polygons from cost points using OSS for web app

This is related to a previous question I've asked: Create filled contour map with GRASS I've created a point layer using OpenStreetMap data and pgRouting's driving_distance() function, where the ...
10
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1answer
2k 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 ...
45
votes
8answers
58k views

How to create polygons with straight lines and right angles in QGIS?

When creating a polygon, how do I do it so that the lines are straight (90, 0 degrees, etc.) and when I create corners they can be right angles? For instance, how do I create a perfect square or ...
4
votes
1answer
143 views

Looking for HowTos or Examples of Presentation Platforms targeting Management/Clients

Any good ideas about using Google Earth to present self contained geospatial data&app to a client or senior management? The broader issue being explored here is that many of our clients are not ...
65
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7answers
40k views

Generating Tiles with QGIS?

Is it possible to generate map tiles from QGIS? I guess QGIS Server must have a way to do it, but is there a way to just generate the tiles and save them to disk? With the new symbology renderer ...
2
votes
2answers
339 views

Is there a way to save manual QGIS changes to Postgis to SQL script?

I am manually editing a Postgis layar with QGIS and would like to export these manual changes in the form of an SQL script. This way: I can do it automatically next time i need to it is easier to ...
9
votes
2answers
4k views

Formatting Dates in QGIS labels

I would like to display a date field as a label. The data is from a shapefile. The field in question is a date field. When I use the date field for the label, it displays in the yyyy/mm/dd format. I ...
2
votes
2answers
334 views

File paths in a PostGIS Table in QGIS

I have a PostGIS table which I have stored the location of some viewpoint photographs. I would like to store the location of the photo file in a field, but when I add a file path in the attribute ...
11
votes
3answers
11k views

Shapefiles and OpenStreetMap data do not overlap in QGIS?

So I'm pretty new to GIS, and I'm working on a mapping project using data for Vancouver, Canada. I want to combine OpenStreetMap data along with data provided by the City of Vancouver. But the City ...
4
votes
2answers
1k views

How to merge street layers in QGIS for exporting to PostGIS?

Is there any way of merging lots of street data in QGIS and getting one layer for exporting it to Postgresql? I know one method using mmqgis "Merge Layer" tool. It works in Ubuntu but not in Windows....
1
vote
1answer
2k views

How to solve an installation problem involving QGIS, Python, and a plug-in?

In an attempt to get the plugin "Profile Tool" working, I installed geoslib and python Shapely 1.2.10 module as requested using following: sudo port install geos Then install Shapely once downloaded:...
5
votes
2answers
921 views

Invalid Geometry Error after ST_ConvexHull

I've a Postgis table of around 80,000 points and want to be able to populate a second table summarizing the data with convex hulls based on points with a common attribute. For example, the data ...
3
votes
1answer
230 views

QGIS 1.7 + MacOS 10.6 : georeferencing from map canvas bugs

I am experiencing issues with the gdal plugin to georeference a raster. It works fine when I enter the coordinates manually but it does not work when I try to link the plugin with the map canvas. ...
2
votes
1answer
495 views

How to move labels in QGIS using the old labelling method

I would like to use the new labelling method in QGIS, however it does not display labels for all of my polygons. If I use the old labelling method (in the properties dialog) the labels display fine. ...
48
votes
8answers
26k views

Comparing QGIS and gvSIG? [closed]

Many debutant GIS users are asking me which one is better QGIS or gvSIG. Since I use Qgis and I don't have any experience in gvSIG, I aways say that both are very nice softwares and the chose is a ...
10
votes
3answers
6k views

Generalizing Polygons to MultiPolygons in GeoDjango?

I set up a model with models.PolygonField in geodjango, using postgres as database. I try to import shp into postgres. The problem is, shp (compiled with QGIS) mixes polygon and multipolygon, hence it ...
22
votes
6answers
30k views

Moving vectors to specified coordinates in QGIS?

I have a layer of vectors located around, say, (100, 100), and I want to move them to new coordinate like (1000, 1000). How should I do it using QGIS?
78
votes
5answers
48k views

Visualising WKT geometry string in QGIS

Is there a simple tool in QGIS to graphically visualise geometry formatted as text? Example geometry: POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 6337246,571178 6337246)) Result: A ...
20
votes
2answers
3k views

Polygon gradient fills / tint bands in QGIS

Is it possible to use a gradient fill on a polygon in QGIS? I would like to have my polygons with a colour at the edges, fading to clear/white as it moves away from the edge. The majority of the ...
10
votes
2answers
3k views

How to label raster cells in QGIS?

I try to show a small resolution raster file in the QGIS Print Manager tool. I would like to show a small label with each cell value (position - circa middle of each cell). How I can do it? Is there ...
11
votes
7answers
24k views

Copying attributes from one polygon layer to another?

I have a problem that I can't seem to get my head around. I have two polygon layers: Polygon A - is a subset of polygon B with the same fields and has identical polygons to Polygon B Polygon B - has ...
7
votes
2answers
690 views

PostGIS uuid type not visible in QGIS or GeoServer

This is probably a simple question, but nothing comes to my mind right now. I have created a view in PostGIS containing multiple columns, including one column of data type uuid. When I try to ...
6
votes
2answers
1k views

How to Match Point Data in QGIS?

How do I match the same points (WGS84) in two different point layers? I want to get the points that lie exactly upon each other in the two datasets.
15
votes
2answers
67k views

Changing unit of measure from degrees to meters in QGIS?

I am running QGIS 1.7.0 on windows, and I donwloaded a shapefile of census block group boundaries from TIGER. This file appears to be in the WGS 84 coordinate system, and when I open it in QGIS the ...
7
votes
2answers
3k views

How to calculate perimeter of polygons in Quantum GIS?

Is there a way to calculate perimeter of polygons with the field calculator of qgis, like there is for area calculation?
16
votes
2answers
813 views

How to clean such a bad shapefile for routing?

I am trying to clean a shapefile to make it usable for routing with pgrouting, postgis, postgresql. Here an intersection, it seems to be connected but when we zoom …. It is not: Same here : Here ...
3
votes
1answer
3k views

Georeferencing with Quantum GIS and reprojecting to EPSG:900913

I'm trying to reproject a map to EPSG:900913 The image I'm reprojecting is the following http://i.imgur.com/HmfLW.png I'm using the cities as reference points obtaining the coordinates from Google ...
48
votes
5answers
21k views

Smoothing DEM using GRASS?

I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough because the area is near flat and the DEM is 90m in ...
33
votes
3answers
56k views

How to Add OSM Layer to QGIS 2.X

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 1.7.0-Wroclaw ...
8
votes
4answers
11k views

Is there a layout view in Quantum GIS?

Is there a layout view in Quantum GIS (something similar to ArcGis layout view) ? Anyway I am looking for tutorial or some good practices how i can prepare a nice map to print in Quantum GIS.
11
votes
1answer
1k views

Snap line layer to network in QGIS or PostGIS

I have GPS data I've taken of bus routes, and now I'd like to snap it to my road network. Both layers are line layers in a PostGIS DB. I'd like to use either QGIS or PostGIS, but if I have to go with ...
4
votes
5answers
7k views

When labelling polygons, not all labels are displayed - QGIS 1.7.0

I am trying to create a simple map of Mexico showing the state polygons and their label. The state shapefile is from here, and the specific file is the first one from the top (Áreas Geoestadísticas ...
7
votes
1answer
15k views

How to change projection and show latitude / longitude in QGIS?

I am new to QGIS and pretty ignorant with the subject, but I want to be able to see the latitude / longitude of a point (with a mouse click) in Quantum GIS. I imported a shapefile (roads of finland ...
11
votes
4answers
2k 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. ...
7
votes
1answer
2k views

How to create a polygon from other polygon boundaries?

I want to write an algorithm that creates a polygon inside a hole made by a set of other polygons. It's something like a flood fill and it's like the "boundary" tool in Autocad. The image shows an ...
13
votes
15answers
43k views

Redefining nodata value into zero in QGIS

I have an image which I clipped with an AOI polygon. The contour area was set to pixel value = 0 and I have a nodata value of -32768. I want to redefine the nodata value into zero. I used to do this ...
2
votes
0answers
269 views

RT Sql Layer plugin giving an error [closed]

I am trying to use the aforementioned plugin with QGIS 1.7 and Postgres 9.0/PostGIS 1.5. Added a PostGIS spatial layer w/out a problem and then clicked on the RT Sql layer button which displayed the ...
12
votes
2answers
8k views

Is there any 'Auto-complete polygon' tool in QGIS?

Is there any 'Auto-complete polygon' tool in QGIS, similar to the one existing in ArcGIS?
16
votes
7answers
31k views

How to delete fields in QGIS?

When is the option to delete field in an attribute table enabled in QGIS? I'm in editing mode and still am not able to delete a field...
3
votes
1answer
2k views

How to update only a single vector layer in QGIS map canvas?

I want to update a single vector layer as I am working on 8 vector layers and they are getting fast data from serial port so for updating I use mapCanvas().refresh() which refresh all the layer and I ...
13
votes
2answers
17k views

How to join external tables with a shapefile's attribute table in QGIS?

I need to join a .csv table into an attribute table of a shapefile. I wanted to do this with QGIS and i don't seem to find anyway of doing it. I know that the mmqgis plugin does it, but my shapefile ...
0
votes
1answer
330 views

QGIS 1.6.0 problem during printing & export to PDF

When trying to print or export my map to pdf something happens to my document. When trying to print, the outcome always results in the printer producing a solid grey rectangle, and when I try to ...