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

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0
votes
2answers
735 views

How can I download maps from mapquest?

I need to get a detailed map for my own purposes. I need it detailed as much as I can see the buildings (like google map hybrid mode). I went to http://open.mapquest.com/ but I couldn't find the way ...
2
votes
0answers
29 views

How to load a style from POSTGIS in PyQt

The thing is that I have four styles I have created in QGIS through the GUI and saved into a postgresql database. I can see them in the table named layer_styles I have seen similar questions asking ...
0
votes
0answers
5 views

Need to edit info to new column for label and concatenate information which is alphanumeric

I need to end up with the following: Jones, H.L. A-345 The data is entered into Survey Name (as string). Survey Abstract #is entered as "345" I need to add "A-" to the number, and then concatenate ...
1
vote
0answers
37 views

Unable to stylize as pseudocolor render type

In a raster layer's Style Properties, I can choose pseudocolor render type, and choose a color ramp and classify the raster. However, when I click the 'Apply' button, or click 'OK', the ...
15
votes
2answers
9k views

How to rename attributes/fields in a shapefile attribute table?

I would like to rename some fields in my attribute table: Like rename XRF_N3in something else. It seems quite a easy issue but I don't find any information about how can I do that... I've QGIS 1.8 ...
1
vote
1answer
22 views

How to change the border style of a symbol

In my maps I have a symbol, his type is polygon, I want to change the line style of the border, actually is solid , I had to put it in dash Is there a simple way to change it ? i think to the ...
1
vote
3answers
47 views

Grass toolbar for QGIS 2.10

I don't see the GRASS toolbar in QGIS 2.10 (Pisa). There are still GRASS commands in the Processing toolbox. I know there was some upgrade of GRASS for 2.10. Is the toolbar not available anymore? If ...
0
votes
0answers
19 views

How to edit a shape which the toggle Edit buttom is noot enable in QGIS?

I just download a shape file (polyline) from internet and I would like to do some modification in the line, but the Toggle Editing buttom is not enable. It seems that the file is locked and is not ...
2
votes
1answer
32 views

How to find if map layer registry is empty?

In my script I want to open layer named my_layer if it is in the map layer registry. I use following code for it: inputLayer = QgsMapLayerRegistry.instance().mapLayersByName("my_layer")[0] If not ...
3
votes
1answer
925 views

QGIS python - reference a layer in the table of contents

I'm trying to create a plugin for QGIS using python, But need some help. I want to 1.Zoom to a layer and 2. make the layer visible(switch off or on). But I have managed to zoom to an active layer by ...
2
votes
2answers
29 views

QuickOSM returns no result

I am trying to download the polygons for the Umweltzone Heidelberg from OpenStreetMap using QuickOSM in QGIS. I queried by name as shown in the screenshot: The corresponding OSM script looks like ...
0
votes
0answers
21 views

Fail in searches on the joined table data

When a table is joined to a standalone table, the searches on the joined table data return a fail. Is there another way to solve this inconvenient without save the layer with joined table under a new ...
2
votes
0answers
17 views

PyQgis: How to access a deleted features attributes (before committing)

I have a signal setup for a feature deletion event on a layer: self.layer.featureDeleted.connect(self.feature_deleted) When I try and grab an attribute from the deleted feature on the slot, a ...
3
votes
0answers
300 views

Create a path following a road, interpolating from a set of points

I have several hundred vehicular routes within a city from which I wish to create shapefiles. These take the form of directions such as "From Green Street, turn left into Brown Street, Right into ...
1
vote
1answer
28 views

Polygons in one layer have different attributes

Is it possible in PyQGIS to have in one layer more polygons and some would have one set of attributes and another different? E.g. Polygon_1(name, size, average_age), Polygon_2(name, size, ...
1
vote
1answer
18 views

Updating a column in MapInfo based on Symbology or colour

I am transferring a large dataset from MapInfo (V 12.0.2) to QGIS (V2.8.1) and I want to be able to create a column in the MapInfo attribute table that differentiates features with different ...
4
votes
2answers
63 views

How to run qgis scripts in parallel across remote server(s)

I have a stand alone python script using qgis that I wrote with the help of the SE question here The script takes three arguments being; an input file path, an output file path, and another input ...
2
votes
1answer
279 views

How to deal with clipper error “cannot compute bounding box of cutline”?

I have merged about 20 OS tiles in to a single raster and I am trying to clip the merged tiles using a single polygon which itself was created from a small number of ward boundaries, merged using the ...
1
vote
0answers
12 views

How to scale SVG symbols which are not label background on zoom level in QGIS

I need to scale the SVG symbols on zoom level. @Underdarks answer in the posted question did not help me thus I can't set the SVG symbols as label background for I have labels which should not be ...
1
vote
3answers
241 views

Free printable background map: land use, rivers, etc

I am looking for a free printable background map of europe which should look more or less like the OCM landscape: land use, major rivers, coast lines Is there any WMS or raster set whiche enables me ...
1
vote
1answer
27 views

How to get PostGIS DB name from QGIS layer?

I'm writing a custom Processing script that needs to know which database connection a vector layer resides in. I can't find anywhere in the API a function to return this information from a layer. So I ...
1
vote
1answer
12 views

Rendering of SVG for layer symbols using QGIS?

I have a little problem with the rendering of SVG for layer symbol. I want to creeate a categorized symbol to show different style of buoy I have for that two icons the first is an half circle ...
3
votes
1answer
19 views

How can I create a QGIS plugin that needs an external Python library?

I’m trying to enhance QGIS's Profiletool plugin by adding DXF export functionnality. For this, I need to to import dxfwrite library. As it's installed on my computer, i added the following lines to ...
5
votes
2answers
117 views
+50

Creating disease risk map in QGis

I would like to create a risk map using RFE Data and Tiffs but now I realised that I actually have no idea how. I have dowloaded .Tiff(Region), .hdr and .bil(Rainfall/RFE) files from the USGS page, ...
0
votes
0answers
8 views

Normalized icon for BOYLAT

I try to find normalized icons to use for the BOYLAT ( lateral buoy ) I find description, but for the boylat it seems that different shape to show different buoy link for the description ...
1
vote
1answer
370 views

Export to Open Layers plugin doesn't work with Raster and WMS

i am trying to export a Qgis_2.4 project to openlayers using the "Export to OpenLayers" plugin. I cannot export raster layer. I am not getting any error message, but the raster layer doesn't appear ...
1
vote
0answers
16 views

Why do pixel (cell) values change for 32 real NDVI values when taking from Multispec to QGIS?

Landsat 5 values change from normal NDVI -1 to 1 when created in Multispec as a 32 bit signed data image. When adding the raster layer in QGIS, the value range changed to 0-255. How does one ...
1
vote
1answer
13 views

Opening MapInfo .TAB file containing text objects in QGIS?

Whenever I try to open a MapInfo .TAB file that contains text objects in QGIS, the text objects are converted to point objects. Any help, please?
1
vote
1answer
42 views

Loading Natural Earth *.prj file into QGIS 2.10.1?

I have found solutions for this problem in other versions of QGIS, but none that apply to the newest version 2.10.1. Whenever I try to import a Natural Earth Raster projection that is a prj file I get ...
2
votes
1answer
15 views

Inserting image in an attribute table in QGIS Composer?

I'm trying to create second page of map atlas. In this page I need to show all records in the range of current atlas page. I've used Insert Attribute Table tool in composer and it worked. But I need ...
1
vote
2answers
22 views

How to put a frame around a legend using QgsComposerLegend?

I can already see this being a simple answer but I'm stumped with this. I want to create a frame around a legend created by a PyQGIS script Code snippet is: legend = QgsComposerLegend(c) ...
3
votes
0answers
43 views

Soft edges for interpolation output

I've built the following heatmap using QGis 2.8.2's Raster->Interpolation feature. It looks almost the way I want: The background layer is Google Maps tiles by using the OpenLayers plugin. ...
1
vote
1answer
25 views

QGIS2WEB Plugin (openLayer3) for QGIS not exporting raster images

I am using the QGIS2WEB plugin for QGIS. I have added vector features as well as a raster image (.tif or .ecw) format. When I try to export the webmap, all the layers are visible expect the rasters. ...
6
votes
1answer
133 views

How to create an Atlas based on point attributes?

Essentially I am wanting to produce an atlas based on a categorical field in a point layer. i.e. I have a point layer of childcare providers with the categorical field "Provision". I've categorized ...
5
votes
5answers
584 views

How to create a label formatted like “ 1,000' ” from a numeric field?

This question builds on a previous question I came across at gis.stackexchange: How to easily edit attribute data using Regular Expressions? Perhaps someone can point me in the right direction? I ...
1
vote
1answer
341 views

QGIS Invalid object name 'geometry_columns' QODBC3:Unable to execute statement

I was using Lisboa 1.8 with SQL Express and tables with geometry. Connections were working with 1.8 and are working with ArcGIS, so I know my tables and geometry are fine. I installed 2.4 Chugiak, ...
1
vote
0answers
14 views

how to make rectangle selection by mouse on my map(world shape file) in qgis in python

I want to make a rectangle selection using the mouse on my map (world shape file) in qgis in python and extract the lat lon of the selection area but I don't understand how to do it. I don't have any ...
5
votes
4answers
237 views

Is there a quick way to clear all attributes from a layer but leave the polygons in place?

I have a layer with several polygons, each of which has data in over 100 fields. I need to create a new layer with all the same polygons, but with all their data fields blank (set to 0, Null or empty ...
1
vote
1answer
24 views

How can I check in QGIS python if an atrribute is included in my layer?

I use the following code: for field in self.layer.pendingFields(): if field.name()=='elevation': do this else: do that Although there is an elevation attribute in my layer ...
2
votes
2answers
3k views

How to access attribute data type in QGIS?

I've been developing a plugin on QGIS platform using PyQGIS. So far plugin does the following: You can select any feature of the already loaded vector layer in QGIS. After selection, plugin displays ...
2
votes
2answers
963 views

Calculate area covered by a particular raster layer within polygons in QGIS

I am trying to extract information on vegetation cover within a set radius of point locations (my sites). I have succeeded in creating a new vector layer of circles with a 5 km radius around my sites. ...
2
votes
0answers
47 views

Create Indexes Within a View? How could I Speed up Spatial Queries Over a View?

I´m trying to add a view from postgis using QGIS, what´s facile. The problem is that it´s taking too long to load it and to perform any kind of operation, for example, as simple as counting rows. It´s ...
2
votes
1answer
30 views

what is the “clip” feature for color ramps?

In the singleband pseudocolor band rendering, there is a boolean checkbox "clip". What does this do? I don't notice a difference in my maps and haven't found documentation for it. Thanks
4
votes
2answers
191 views

Boundary from Points

I have a point cloud and need to process a very detailed boundary around the outer points. Is there a tool in QGIS? Convex hull is not detailed enough. Thank you!
2
votes
1answer
25 views

QGIS: Finding electric network loops

With QGIS, how can we analyse an electrical network to find loops? Using Python is not a problem, however there is not a solution in the QGIS Python API. The QgsGraphAnalyzer has dijkstra and ...
0
votes
0answers
17 views

Problem using EPSG:3395

in my application I use OGC:CRS83 for the coordinatereferencesystem, but now I had to change it to EPSG:3395 when I call : mQgsCoordinate->createFromOgcWmsCrs("EPSG:3395") there is nothing in ...
1
vote
0answers
10 views

Unable to make qgis build in cmake

I am trying to build qgis without any change in source code which i have downloaded from github using clone and i have download OSGEO4W from qgis.org and the same is installed in c drive. I have ...
1
vote
2answers
61 views

One-to-many join in QGIS

I am looking for a possibility to make a one-to-many table-join in QGIS. I have a shapefile with postal codes and would like to join them with survey results (more than one). In other words, there ...
0
votes
1answer
22 views

What is the meaning of DN and DRVAL2 categorie?

I try to find the meaning of the categories DN and DRVAL2 when I used them in the command: lrenderer = new QgsCategorizedSymbolRendererV2("DRVAL2" , Categrories ); Is there any tutorial or ...
1
vote
0answers
18 views

Error in Editing Point Shapefile: I can't add a new point feature

I want to add a point to a point shapefile. I place the cursor in an empty field. The strange thing is that the point of the point shapefile that is nearest to the cursor is highlighted. If I click ...