Tagged Questions

1
vote
2answers
42 views

How to select two points on a map using QGIS?

I need to select two points on a map in QGIS. I selected the element selection tool in menu view and I want to select two points. How can I accomplish this? Are there other tools or methods to ...
3
votes
1answer
46 views

How to delete points from CSV point layer?

I have a point layer produced from importing a Delimited Text Layer and I would like to delete some points. It seems that it is not possible to toggle editing in a point layer. How can I delete the ...
-1
votes
1answer
55 views

QGIS and Python - create line with multiple points in postgis

How can I create a line, with Python functions, with many points that are records in Postgis? Thank you
0
votes
0answers
29 views

Assuming nearest point for a region

I'm mapping agricultural cropping systems in Brazil using QGIS. From satellite images I got an raster file with 5136 x 5136 pixels from my field work. Now I need to associate many soil/climate ...
0
votes
1answer
78 views

Aggregate points with same values to polygons

I have a shapefile with 2M measurement points (each measurement point has a resolution of a 1/10). How can I aggregate points around each other if and create polygons out of it? They do not have to ...
1
vote
0answers
78 views

How to calculate average value within a polygon(in Qgis with Python)?

Now I have a point and polygon shapefile and I want to calculate the points' average value within each polygons How to do it with python? I tried to find out but google gives me a lot of raster ...
1
vote
0answers
60 views

How can I move two layers at once in QGIS?

I'm trying to move two digitized layers, one containing points, the other polygons to a different location at the same time. QGIS doens't seem to allow this. Even if I select both layers and features ...
0
votes
2answers
59 views

Manually add a new point to PostGIS table [duplicate]

I did accidently delete a table row - or well, in fact a whole subway station. My attempt to solve the problem was this PostGIS function: ST_GeomFromText('POINT(coordinates)') But then PostgreSQL ...
2
votes
1answer
75 views

How does Flow Mapper Plugin work?

I downloaded the Flowmapper plugin for Qgis and I can't seem to find any information on how it is supposed to work... Also the text seems to cut-off and not fully showing for the input fields so I'm ...
5
votes
3answers
119 views

GIS file format for space and time data?

I need some advice with GIS file format choice. Here is my problem: I have about 100 stations. At each station water temperature is measured daily for 1 year I want to load this data to QGIS and be ...
1
vote
2answers
63 views

Layers with same coordinates not lining up [QGIS]

I have a project where I have a few layers (State of Texas, cities, roads, etc.). They are all resaved and projected to NAD83 / UTM zone 14N EPSG: 26914. The project CRS is also NAD83 / UTM zone 14N ...
0
votes
1answer
61 views

Split polygons and extract points

I have a polygon file with 90 adjacent polygons. I also have a lat/long point file that overlaps the entire surface of the polygon file (170,000 points). My problem is that working with all of the ...
5
votes
1answer
223 views

QGIS or Postgis - How to split polylines with a point layer?

In QGIS, I would like to split the polylines in a layer loaded in the workspace with the points in another loaded layer. If a point intersects a polyline, this polyline should be transformed into two ...
1
vote
1answer
110 views

QGIS create layer with the points of the beginnings and ends of a polylines layer (without duplicate points)

In QGIS, i would like to create a new layer containing the beginning and end points of a polylines layer, but without the duplicate points that would result of adjacent polylines.
5
votes
3answers
195 views

How to create different diameter circles round points?

I want to map a tree survey. I am thinking that I will plot positional points of the trees and then add other data like tree type etc. to the attribute table later. Is there a way I can have an ...
4
votes
1answer
105 views

QGis 1.8 fails to rotate point geometries with rule-based style

I have to do some visualizations in QGIS (1.8.0) and up to now I've been very happy with the new Dialog "Layer Properties -> Style", using the rotation-field to rotate Point-Geometries visualized by a ...
2
votes
1answer
151 views

Is it possible to place a point at a coordinate in QGIS?

Is it possible to place a point at a coordinate in qgis? I have a map, using irish grid reference and wish to place a point at an exact 6 digit coordinate. Is it possible to do it. Previous to this ...
1
vote
0answers
90 views

Creating points along lines? [duplicate]

Possible Duplicate: How to create a point along a line given distance How to create equidistant points in QGIS? I have some road survey data and each line has an individual value and ...
5
votes
0answers
91 views

Moving points onto lines (~neighborhood)

I do have two vector layer, of which one is a point layer based on "events" by remote sensing and the second one is a line layer from local research. In my case these are earthquakes and tectonic ...
3
votes
1answer
93 views

How to determine error radius of given points

I am running QGIS 1.8.0 on a 64-bit Windows 7 platform. Given multiple points with different (but close) coordinates, how do I automatically create a new point that programmatically takes into ...
5
votes
2answers
92 views

How can I join a spreadsheet to a point layer?

I have a layer with point data for the grave positions in our cemetery. We are gathering data from each headstone. If I enter the data to a spreadsheet can I later associate the spreadsheet with the ...
4
votes
1answer
256 views

How to remove duplicate point features?

I have created many .gpx datas with my Garmin device, but due to the amount of data, I have imported the mapping data from my device several times (also because I didn't want it to be lost)... As a ...
0
votes
2answers
81 views

Why does a track point layer attribute table have no positional information?

I imported a track log in GPX format to QGIS. The track had two layers, the track points and the track, a smooth line joining the track points. Why does the attribute table for the track points have ...
0
votes
0answers
29 views

Point to Polygon [duplicate]

Possible Duplicate: Create new polygon layers from postcodes latitude & longitude I'm running QGIS 1.8.0 I have a list of points that I need to convert to one polygon. So far I have ...
3
votes
3answers
236 views

How to extract POINT from a [LINE|MULTILINE]STRING

I'd like to create a vectorLayer in QGIS to display all the points that form a LINESTRING or a MULTILINESTRING stored in a PostGIS DB. I think that I need to transform all points of LINESTRING (or ...
3
votes
1answer
110 views

How to create a line with start and end points which are in another layer in QGIS?

In my map, there are lots of points in layer A. I want to make a line layer B and I want to make start & end points of lines snapping to points in layer A manually. Can I use points of layer A as ...
1
vote
1answer
113 views

Is it possible to filter points that dont make sense compared to neighbour points?

I have a point shape (10.000 Points). Before interpolating theses points I need to filter them with a statistical background. Is there a tool or something I could use? Is it possible to select / ...
3
votes
1answer
220 views

Can I move points by editing x/y in attribute table?

Im new to QGIS and I just cannot figure out how to do this one hopefully simple thing: I have a bunch of points in shapefile and i need to move some of them around by hand / coordinates. I've ...
4
votes
1answer
273 views

How to automate the drawing of polygons (square) around a number of points in QGIS?

In QGIS (or alternatively any other scripting + GIS stack), how can I automate drawing a 100km x 100km square around a number of points, with the point being dead in the center? I'd need to loop ...
5
votes
4answers
3k views

How do I create point features with exact (manually entered) coordinates?

How do I create point features with exact (manually entered) coordinates i Quantum GIS (QGIS)? I get precise gps coordinates from a survey team which I need to add to a point layer. What I want: -Add ...
1
vote
1answer
194 views

How to find the nearest single point?

I have two shapefiles containing each one set of points, set A and set B. One set is my random selection (set A), the other is a list of communities (set B). For each point of the random selection ...
0
votes
0answers
250 views

How to do a spatial join if QGIS 1.8 keeps crashing?

I am trying to perform a simple spatial join (adding polygon data to points) in QGIS 1.8: target vector: points join vector: polygons take attributes of first located feature keep all records ...
4
votes
1answer
264 views

Is it possible to create a point within a Polygon (not a centroid)?

Is it possible (without writing Python code - sorry I'm not a developer) to create a point layer from a polygon layer but ensure the point is within the polygon? The ftools centroid tool is cool but ...
2
votes
0answers
335 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
7
votes
2answers
610 views

How can I create random points along a polyline in QGIS?

I am trying to create random points along a polyline shapefile in QGIS. Basically, like the 'random points' tool in 'research tools' but for polylines instead of polygons. I have tried converting ...
3
votes
2answers
625 views

Update point coordinates in QGIS after manually moving locations in edit mode

I have imported point coordinates from a database, but I need to manually adjust a lot of the locations. Is there a way for QGIS to automatically update the point locations in the attribute table ...
4
votes
4answers
2k views

How do I create a line between two points with a common field?

Does anyone know how I could create a line between two points that have a common code? For example: I have the start and end point of a pipe as a lat/long for a network of pipes, each with a ...
1
vote
1answer
125 views

QGIS - WGS84 to BC Albers reprojection no curved lines, any idea why? How to snap a line to a point?

I am trying to learn a bit about QGIS. So I thought I would drop in some layers of my Province and then recreate some points representing the BC Albers Central Meridian, and the two standard ...
3
votes
1answer
1k views

QGIS calculate distance of point along a line

I have a polyline (movement path) and points recorded along the line. I would like to calculate for each point the distance along the line in Quantum GIS. I hope for a result which will add a new ...
4
votes
3answers
2k views

How do I convert a polygon into a point?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)
2
votes
1answer
1k views

How to add points to a point vector layer - QGIS

I have a point layer with multiple data points in QGIS, but I want to add some extra data points to it and adjust some info that we missed because the ground was wet and we needed to go around it. I ...
2
votes
2answers
145 views

How to modifiy how selection highlights are displayed?

I have got a layer of points that are showed with a litlle symbol. When I select one, a red square comes around it. The problem is that this points are inside other layers (polygons) and some of them ...
3
votes
1answer
927 views

Calculating distance to points in QGIS

Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
3
votes
2answers
2k views

How to use Distance Matrix tool in QGIS?

I have a point data set. Now there are cluster of points based on a field. So I take out one such cluster which has points with same field.I want to find distance between all the points in cluster and ...
6
votes
2answers
279 views

How to Match Point Data in QGIS?

Please, how do I match the same points (WGS84) in two different point layers? Like I want to get the points that lie exactly upon each other in the two datasets.
10
votes
3answers
2k views

How to join attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
1
vote
2answers
1k views

Hyperlink relative paths to files in points layer in QGIS?

I would like to add hyperlinks to each point in a points layer in QGIS 1.7.0 running on Mac OS X 10.6.7, but I have several requirements: (1) Each hyperlink has to be a relative path to the linked ...
11
votes
5answers
9k views

Get list of coordinates for points in a layer?

I've got a layer in QGIS that is comprised of points. Its attribute table doesn't have the corresponding x y coordinates for each point. Is there a way for me to extract a list of coordinates for ...