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

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176 views

Why is there an offset between reprojection results of ArcGIS and QGIS from PSAD56 to WGS84?

I did a comparison of file system PSAD 56 to WGS 84 with arcgis and qgis and the difference is 8 m, why is the difference? This is a points file (shape) and it is in UTM Zone 19S.
7
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1answer
517 views

Creating contours with meaningful values from point data

I recently obtained a CSV containing the locations of all recorded bicycle accidents in Boston over the past few years. As an avid cyclist, I'd like to create a simple contour map that draws attention ...
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1answer
4k views

Import PDF to qgis

i have a PDF containing a region of Baltimore city that contains lots of polygons in it. you can download it from here: ...
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1answer
53 views

“merge” a raster data set on precipitation with a shapefile of administrative districts.

I'm currently using QGIS 1.8.0 I would like to "merge" a raster data set on precipitation with a shapefile of administrative districts. Basically my the aim is to figure out the precipitation in ...
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0answers
217 views

how can quantum be installed without administrative rights?

I have the impression from searching that this may have been possible with earlier versions but I don't know if it is possible with version 1.8. Thanks
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0answers
84 views

Mapping point data according to it respective value

The project I am trying to do is to map sum water quality (based on trace metals) data into QGIS. Each of the trace metals have their respective values and need to represent their concentration ...
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4answers
103 views

Add only unique features from another shapefile

I've got a problem that I am sure at least one of you have dealt with. I'm new to a company that makes use of a rather large database of point data. For whatever reason, the woman who was here before ...
4
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1answer
61 views

Dividing map into features with invisible divisor lines using QGIS?

I'm working with QGIS 1.8.0. Is there a way to divide a map with a grid but make the divisor lines invisible? I have a shapefile as the one in the left and I want it to see as the one in the right but ...
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1answer
85 views

Conversion of coordinates of “Bochum coordinate system”

I need to convert historic coordinate data into more recent Gauß-Krueger data. Specifically, I need to convert "Bochum coordinates" used till 1960 in the local coal mines into DHDN/Gauß-Krüger zone 2 ...
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1answer
446 views

QGis Save Raster as Rendered Image

In QGIS 1.9.0 Master, when you right click on a raster in the Layers Panel and select "Save As", you can select the output mode to be "Raw Data" or "Renedered Image". When selecting the Rendered ...
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3answers
644 views

is there any way to run a GIS (Esri, Qgis or mapinfo) on a Windows8 RT tablet?

I am looking for a good idea to run a GIS program on a Dell XPS 10 with the Wind.8 RT.Thanks for any
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1answer
76 views

Counting and sum by two layers

I´ve got to layers, both polygons. Layer 1 consists of propertiers, where ID is individually names. Layer 2 consists of lakes. The query I want is: Total count of squaremeters of lakes for each ...
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0answers
124 views

How to convert a symbol style set for ArcGIS for use in QGIS?

Is there a way to convert a symbol style set for ArcGIS for use in QGIS? There are symbols used in Incident Command I would like to use in QGIS, but can only find a style set for use in ArcGIS. The ...
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0answers
49 views

Can I use the PyQgis QgisPluginLayer to create heatmaps?

I am working in an application to generate maps from a bunch of MIF/MID files, I already created almost all the maps that I need, but, now I want to create heatmaps. I can't find any way of creating ...
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3answers
648 views

Calculating MCP in QGIS

QGIS 1.8.0. Scipy installed. Statsmodels installed. Using Sextante to try to calculate MCP. When I run the MCP calculation from the Toolbox, a layer is added to the file, but the layer doesn't ...
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1answer
65 views

Using LANDFIRE data in QGIS

I am wanting to use the LANDFIRE rasters in QGIS, but I cannot get all the files to load. I load the w001001.adf file in the directory that contains the data, but I cannot access the attribute table, ...
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1answer
300 views

Adding UTM Zone Number to Coordinates

The computer program that I'm working with requires an 8 digit UTM Easting for the coordinates of shapefiles (i.e., the UTM zone number must be included with each coordinate within a shapefile). The ...
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2answers
388 views

Vehicle tracking by QGIS

I need to do routing for a vehicle. A map with detailed turn-by-turn driving directions should be generated. For example, it should be like car race game in which the map with vehicle tracking is ...
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0answers
159 views

Spatial Precision for Editing in Multiple GIS Clients

I have something I'd like to discuss, I'll try to explain it first, why it's important, and I'll explain how ArcGIS handles the issue, which I think is a good way to handle it. Finally I'd like to ...
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1answer
224 views

Bring trails onto a Garmin nuvi GPS

I seem to be having a lot of trouble uploading Utah Trails onto my nuvi 50 GPS. Is it not possible? The Black hills national forest has a img file that is able to be loaded onto the GPS, but the ...
3
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1answer
429 views

Invert Color Ramp in QGIS

This is a real basic question, but I can't seem to find it. How do I invert the color ramp in QGIS? I am using RdYlGn, but I would rather use GnYlRd. Seems really easy, but I can't seem to find ...
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1answer
234 views

Polygon grid shape file for landmass

I am interested in generating a polygon grid shape file for the landmass of the world. What I have presently is two tables in postgreSQL. Table 1: Coastal area shapefile ...
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0answers
55 views

How do I make vectorlayer with sql on PostGis via python code

I need to make a vectorLayer and fill with the SQL's results on PostGIS via python code. I'm working with python 2.7, QGIS 1.8 and PyQt 4.5 How do I it ? thanks
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0answers
38 views

QGIS adding points using decimal degrees [duplicate]

As duck blind permits are sold, we need to add the location using lat/long. we are working in ArcView now but would like to move to QGIS- Everything I was able to find seemed to deal with importing ...
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5answers
1k views

Display ESRI Shapefiles in a map in a browser. (Not in google maps)

I have a series of shapefiles that I need to render as a map on a webpage. I have an ASP.Net server, although I would prefer something that will work on Linux servers. I would like to find an easy to ...
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1answer
213 views

Can one expose variables to the Python console from a plugin in QGIS?

I have a QGIS plugin that performs a long-running operation, eventually producing and loading new shapefiles into QGIS. (I have this as a plugin rather than just a function that can be called from the ...
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1answer
641 views

How to create a customizabe table in QGIS Print Composer?

I would like to add a custom table to a map layout created in QGIS. I would like a fair bit of control over the look of the table (borders, background colours of the cells, etc.), and it appears that ...
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1answer
87 views

How to know the real size of grid? [duplicate]

Im working with QGIS. When dividing a map with a grid I set in the paramters X=0.1 and Y=0.1. Could someone please explain what does that mean? I mean would the map be divided into 100mx100m squares? ...
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2answers
287 views

QGIS:what does it do “snap gcp coordinates to background layers” in the Georeferencer plugin?

Maybe is too obvious, but I don't find any precise documentation about this checkbox in the georeferencer plugin.
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1answer
86 views

problem in merging adjacent address polygons in qgis

I am having 15 polygon shape files of a sub locality of a city that is having address in their attribute table. I want to merge these polygons based on the address in the attribute table?how can i do ...
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1answer
179 views

How to count number of stores per company per region?

I have two layers. One point layer and a Polygon layer. It is simple to count the points in the polygon layer by the "points in polygon" function. But I also need some more information of the point ...
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2answers
182 views

How to count record points within a given area (electoral district)? [duplicate]

New user to GIS and to QGis but experienced data user. I have shapefiles for a state legislative districts. I have a set of individual voter records that I have geocoded. What I'd like to do is ...
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1answer
84 views

Value Map Attributes to Multiple Files in QGIS

I am hoping someone can share a way that I can some what automatically (none manual) associate a pre-defined CSV file for use with multiple shapefiles as an attribute Value Map. I have a number (in ...
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0answers
111 views

QGIS merge rasters error

I've been trying to merge some raster tiles at work and I've been getting an error message saying I don't have the correct permissions. This works fine on my home pc. Any obvious reasons for this? ...
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0answers
54 views

Borderlines of states subdividing my GRID

![enter image description here][2]I just merged a map of a country with its states, so I went from having 1 feature (the whole country) to 32 features. Is there any way to have the borders of the ...
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1answer
33 views

What is the meaning of “MULTIPOLYGON EMPTY” Message?

I am trying to run ST_Intersection function. SELECT ST_AsText(ST_Intersection(ST_Point(42.729123082000058,-96.619302355999992), ST_Point(42.72899715300008,-96.619410439999967))) FROM clu_08aug; I am ...
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2answers
537 views

QGIS Zonal Statistics just gives 'NULL'

Seems like such a simple plugin, but it just won't work. I'm trying to run Zonal Statistics to find the mean value of a raster's pixels within the area of a vector polygon, but all it will give me is ...
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1answer
133 views

Dividing map into features (whole squares)

I'm using QGIS 1.8.0. I divided a map of a state with its municipalities into many features using a GRID (small squares), but instead of creating one ID per feature (one ID per square), it creates one ...
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1answer
1k views

Does QGIS run on Windows Surface with Win RT OS?

I was wondering if anyone has had any success running QGIS on the Windows Surface tablet? Specifically with the Windows RT OS.
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2answers
252 views

Convert ASCII Grid Colorized to Raster

I have an ASCII Grid file + .prj file and can visualize this in qGIS. I can colorize it by going to properties and using a Pseudocolor Ramp. However, I want to export this now as a TIFF / Raster. ...
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0answers
103 views

Problem with pie-charts when exporting them to an image file

I have 3 vector layers: a map of Europe and N.Africa, a line layer, and a point layer (on the top). I have created pie-charts over the points in QGIS 1.7.3, and on QGIS itself, they look fine. ...
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0answers
107 views

how to avoid Intersection of polygons via python code

i am using QGIS 1.8 and i can set the check box in Setting\Snapping Options "Snapping and Digitizing " dialog to avoid polygon intersections and enable topological editing but i am looking for a way ...
3
votes
1answer
145 views

Strange exposure of a PostGIS layer in QGIS after importing OSM data into a database

I've imported a osm layer into my postgres/postgis database. osm2pqsql -E 3857 -c -S /usr/share/osm2pgsql/default.style -H localhost -W -d landslide -U postgres oberpfalz-latest.osm.bz2 During the ...
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0answers
337 views

How to integrate .NET application in QGIS using Python?

In our company we have developed a .NET application that's now integrated with 3 different GIS platforms. Now we would like to make it work with QGIS but we need some help on getting started. I've ...
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1answer
84 views

Why isn't enabling on the fly projection reflected in raster? QGIS 1.8.0

I have imported a map from the Ordnance Survey Open Data website. It is a 50k Street View raster. I have also created a new shapefile layer in which I have created a polygon overlay for the raster ...
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3answers
220 views

Converting .kml to different projection in qgis not working

I have run into a slight problem it would seem. Yesterday I downloaded qgis in the hope that it could convert a .kml overlay of some administrative boundaries from EPSG:3857 (Google maps) to ...
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0answers
119 views

convert vector with multiple attributes to multiple rasters

I have a vector polygon feature with multiple attributes/fields. Ultimately, I want to convert it to a raster 'stack,' whereby each of the attributes/fields will be a different band of the raster ...
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1answer
68 views

Polygons Shrinking and Moving as if CRS Was Suddenly Out of Sync with Project

I long ago set the CRS for a linguistic geography project I'm working on involving Oklahoma data (EPSG:2836 - NAD83(HARN) / Oklahoma North), and I have been closely monitoring that the polygon ...
7
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5answers
1k views

Are there open source solutions for travel demand modelling?

I'm looking for open source tools for travel demand modelling (eg The four-step UTMS). Preferably in a GIS environment. That works well with Qgis, Grass and Postgis. My question is not related to ...
4
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1answer
448 views

Is it possible to open the attribute table using PyQgis?

is it possible to open an attribute table from the python console or through a python script in QGIS? Thanks!