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35 views

Cutting many lines (as rivers) that are outside of a polygon in QGIS

I would like to extract only the vector lines, that represents rivers in my case, inside a polygon. I tried to use the intersection and clipping from QGIS, but couldn't do it. Any help?
2
votes
2answers
63 views

Mistake in Calculating Area or a Bug in QGIS? [duplicate]

I am trying to calculate the area of a polygon following the step by step mentioned in all the questions related to this issues in this website. Nonetheless, the result of the area calculation is ...
3
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1answer
63 views

Hillshades created from QGIS Virtual Raster Tables sometimes have unwanted artifacts

Using QGIS 2.14.3 I tested Virtual Raster Table technology for the first time using two TIF DEMS (NED 1/3 arc-second, projected to EPSG:3338, single band, 32-bit floating point, ~ 5-meter resolution). ...
3
votes
1answer
72 views

Start multiple processes with one action

I am trying to start multiple processes with a single action in QGIS. With Windows commands it is not hard, see here: http://stackoverflow.com/questions/13719174/how-to-execute-multiple-commands-in-...
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0answers
19 views

Upload a raster in postgis

I know this might be a similar question to many others. I have been prompting multiple questions here and on google but I cant figure it out. I have a raster and I have uploaded it into postgis with ...
1
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1answer
53 views

Visualizing interpolation result with three js in QGis

I used topographic map to trace the contours in QGIS. For each line, I added an attribute value (ex. 565, 564, 563 etc). After that, I used the IDW and TIN interpolation methods to create a couple of ...
4
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1answer
62 views

Stratified Random Sampling Tool

Is there a way to produce a certain amount of random points over different classes in a raster in QGIS? I have extensions such as GRASS or GDAL, ...
-1
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0answers
25 views

QGIS and image server

I am lacking in knowledge and wanting to link to the following image service. how do I get this link correct for QGIS ? http://gis.pcc.govt.nz/arcgis/rest/services/Base/Urban_Aerials_2016/...
2
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1answer
43 views

Plugin for fast export selected features from multiple layers

Is there any tool or plugin providing export of selected features from more than one layer on one click? I need to create multiple exports from three layers. Feature from layer one, then feature from ...
-3
votes
2answers
42 views

Finding address geographically? [duplicate]

Is there a way to make Geocode or location address based on a shapefile streets, without using a web service and using QGIS or some open source software?
2
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0answers
48 views

QGIS equivalent of Calculate Adjacent Fields for Atlas

Is there a QGIS plugin available or a processing model to calculate and populate fields that can be used to label the adjacent pages in a map book? Although there are tools to create vector grids, I ...
1
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0answers
18 views

Convert a SHP file set to a categorised ASC raster with Qgis?

I have a shapefile with regolith (soil) data that I would like to use as a categorised raster (say 007_1ASC) in Maxent. The regolith data is in the following files: 007_1.cpg 007_1.dbf 007_1.prj ...
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0answers
26 views

Classification of multiple values at the same point

If I have a point dataset with multiple values for the same geographic location (e.g. residuals from a regression where multiple individuals live at the same location) which I classify using quantile ...
2
votes
2answers
91 views

How do I get the building housenumber from OSM data?

I've made a map in which buildings in a city are displayed using shapefiles from Geofabrik and unfortunately, none of the shapes contain the housenumber. When I download the .osm files from Geofabrik ...
1
vote
1answer
35 views

Geoprocessing in CRS WGS84 and UTM Zone in QGIS

Why do I can't do union or do another geoprocessing two shapefiles with different CRS in QGIS? For example, I want to do union two shapefiles, one shp with CRS WGS84 and another shp with CRS WGS84/UTM ...
2
votes
1answer
63 views

Is there any plugin to Identity in QGIS? [duplicate]

Identity is one of ESRI ArcGIS Feature that clipping feature class by another feature class then union first feature class to the result of clip process. The simple explanation is like this picture ...
2
votes
0answers
42 views

Automatically split line at intersection of nearby shapes/zones

I have a large dataset in QGIS with roads (blue line in picture below) and 3 type of zones (mostly rectangular areas, red and green shape in picture below). My task is to spilt to road into segments ...
1
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2answers
82 views

how secure is data on qgis? [closed]

What is the safety guarantee using the QGIS platform for data storage? I want no data loss and easy access to data when stored. Can passwords be used to safeguard data and how do I give permissions to ...
2
votes
1answer
40 views

QGIS 2.14 Debian Sid - Couldn't load plugin 'processing'

The processing plugin can't load because python import error for QtWebKit.QWebView. QGIS is installed from Debian official repositories. The plugin worked fine until 2.14.1. The error message at ...
2
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0answers
37 views

Aligning layers in QGIS?

I am new at QGIS and am having a problem aligning layers. Possibly I just don't understand how projection works. I have 2 layers: 1) GPS waypoints collected in a GPS UTM zone 55N 2) polygon ...
4
votes
1answer
81 views

How to load multiple vector layers into QGIS' map canvas using python scripting?

I am trying to write a standalone script in python to create a QGIS map canvas. The vector layers I am attempting to load are Shapefiles. Currently, I am able to load each vector layer, add them to ...
1
vote
1answer
58 views

Counting nodes/vertices in large polyline GeoJSON?

I have a large .geojson file (~ 1 GB) of made up of thousands of polylines. My objective is to count the number of vertices (not end points) in the entire file. Is there a python module that is ...
3
votes
1answer
47 views

Create street map with A-10 type grid & index

I need to create a printed map using QGIS with an arbitrary grid superimposed, such as is usually found on street maps.. say A to K on one axis and 1 to 10 on the other. Then I will need to create an ...
1
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1answer
29 views

GRASS/QGIS- “buffer” created with DEM analysis- how to avoid it?

I have, to start, a DEM raster and a shapefile, with random created points, within a given polygon. The DEM raster was clipped with that same polygon. With the DEM raster, I used GRASS to perform ...
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2answers
57 views

Are there roadmap datasets available for qgis?

On ArcGIS.com, you can download public datasets such as road maps. Do these work with qgis or are there public datasets available for qgis? By public, I'm referring to datasets that others have ...
2
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0answers
19 views

get active colourramp form qgis rasterlayer

I m building a pythonscript were i need the active singleband pseudocolour colourband of a raster. I want to give the active colourramp a new min and max value. I can only find examples like this ...
0
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2answers
45 views

how to insert Co-ordinates (LAT. and LONG.) in a map composer of QGIS 2.8

In QGIS 2.8, how to insert co-ordinates (degree, minute and second) in map composer? when I did it, the the X and Y intervals value were showing on the frame instead of actual lat. & long of the ...
0
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0answers
24 views

Raster to categories to shapefiles

I have a raster data file which is the population density. I would like to transfer this raster into a specific number of categories, let's say 5. After that I would like to convert the raster to a ...
2
votes
0answers
20 views

classify colourramp with new min and max value with python

For my script i want to update the existing colourramp of a raster with new min and max value. In my current code is can fill the min and max but can't classify and update the raster. How does the ...
1
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1answer
45 views

How to delete one band from raster file?

I was working using drone imagery (regular camera) and there is this alpha band which is preventing me from doing maximum likelihood classification. I want to remove the alpha band. So far I used ...
1
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0answers
48 views

KML with raster in QGIS

I have a kml file which displays correctly in Google Earth but only as a bounding box in QGIS . What can I do to see the associated raster image?
3
votes
1answer
101 views

How to make some labels BOLD using Expression Builder QGIS

I am using QGIS 2.14 and I am trying to make some of my labels bold to stand out. I'm not sure how to do this using the expression builder. I know this is wrong and I was wondering if someone could ...
3
votes
1answer
32 views

QGIS geoprocessing script, ## hand-over processing-specific information error

I have a QGIS python geoprocessing script starting like this: ## Networking = group ## lIn = vector ## lOut = output vector from qgis.core import * v = processing.getObject(lIn) #[...the rest...] ...
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0answers
28 views

Problem in layer overlapping (qgis)

I want to plot gps pts on qgis (version 2.14.1). I have added the vector layer of SE Asian countries, and added the delimited text layer of my gps pts which included species name, lat and lon. ...
5
votes
1answer
123 views

QGIS display on high resolution screens

I recently changed over to a laptop with a 3200x1800 resolution screen, and QGIS no longer displays properly. Many items and font are too small and almost unreadable. Slight improvements can be made ...
3
votes
0answers
28 views

Rotate feature by angle (QGIS)

Trying to offset a line by 10 degrees, rotating around an endpoint. I've read up on the older plugins and the new Rotate Feature tool, but am having trouble. I am using QGIS 2.8.9 Wien, reinstalled ...
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2answers
53 views

Creating an artificial coordinate system to plot a garden experiment

I am trying to map plant death in a garden experiment. The location of the garden doesn't matter, I just care about each plant in relation to the others. They were all planted on a grid system. My ...
1
vote
1answer
28 views

QGIS- extract raster information into a point return nulls

I have a 1) raster layer and a 2) point layer. I want to extract the pixel value to each point, but it is not working when using this tools (QGIS): plug-in "Point sampling tool" (the new shapefile ...
2
votes
1answer
19 views

How to extend an OSM or raster area in Qgis (into 'No Data' area)?

I need to do the opposite of clipping down a raster (or SHP file) in Qgis (or Gdal, Python etc - even R if someone can provide the script). I have a dataset from Open StreetMap (*.OSM) which includes ...
3
votes
2answers
111 views

How to extract part of string after '*', '~', '-' or '#'

I have strings like this: 234/1-1 3345#5 11/2~10 6754*15 It needed only rightmost part of string after '-', '#', '~'or '*' . I figured how to extract when there is only one sign for example '~' ...
2
votes
1answer
65 views

How to get attribute values from vector features visible in the qgis canvas

I have a vector layer (grid). Currently I select some tiles with the select tool and paste some python code to get information about these features. layer = qgis.utils.iface.activeLayer() ...
1
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1answer
28 views

How to add a node/vertex in a QGIS edit session?

I'm doing some polygon (boundary) cleanup, and am wondering if it is possible to add a node/vertex to a set of selected polygons or even a single polygon. By the way, the QGIS topology editing tools ...
2
votes
1answer
62 views

Update raster color ramp with new min/max values using python?

For a script, I want to update the exsiting min and max of a colour ramp with a new one. In the image you can see what I want to update. To do so I tried to follow this thread. I tested the ...
0
votes
0answers
21 views

USGS ArcGrid converted with GDAL to GeoTiff

I downloaded an USGS NED File in ArcGrid Format. I converted it with GDAL-plugin to GeoTiff. But the dimensions are wrong. Is there a possibility to "stretch" the GeoTiff in the right dimensions? I ...
1
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0answers
54 views

QGIS Attribute Question

I am trying to create a script that will take selected features from one layer and search for the specified attributes related to a column name. in my case 'id'. What I am having trouble doing right ...
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0answers
14 views

Getting Color Infrared from NAIP WMS Server on QGIS

I'm having a terrible time getting color infrared imagery from an NAIP WMS Server with QGIS 2.14.3. I use the "Add WMS/WMTS Layer" button, add a new server with the URL from the WMS link on ArcGIS ...
2
votes
0answers
40 views

problem using qgis spatial join in a python script or modeler : no results [closed]

I'm trying to create polygons from points layers. Each layer contains one point to avoid troubles due to superposition of polygons. I detailed the context here : How can I add output vector to a list ...
1
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1answer
40 views

Road Graph plugin routing on a virtual numeric field does not work

I'm trying to calculate the shortest/fastest path based on a 'dynamic' virtual field with the road graph plugin. The speedvalues are based on a combination of other ppvalues: eg field GFBscore. But ...
1
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1answer
20 views

QGIS Clip of layer with several points

I have two shapefiles: 1) one with several points with a buffer around each separated point 2) another which is a single polygon with several characteristics (therefore it has several polygons inside, ...
1
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1answer
23 views

I keep getting the same error when trying to clip a raster

Error: Cutline feature without a geometry. Consistently get the above error when trying to clip a raster. I have looked at all the other questions relating to this and tried all the 'fixes' however I ...