A geometric element defined by a pair of x,y coordinates.

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1answer
14 views

finding the nearest point outside a series of geometries

I have db with a very large amount of geometries (circles), most of them overlapping. I'm trying to come up with a way to find the nearest point (from your current location) that is not within any of ...
1
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1answer
20 views

Quality estimation of a spline interpolation with barriers

I interpolated the age of minerals for the Inner Tien Shan mountains (Kyrgyzstan) using the ArcGIS tool "spline with barriers". I use ~ 200 points for my interpolation. The barrier that I use is a ...
0
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2answers
208 views

Create multi-line from point in PostGIS

I'm working on an old table where polygons are stored as points. Now, I want to migrate these points to PostGIS and store them as polygons (or multi-polygons). The table structure is as follows: ...
1
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0answers
16 views

OpenLayers - Add points at vertices of line while drawing line

I would like to create points while I draw a line on my map in OpenLayers. That is, at each vertices of a line and at the end points there is a shape like a square, circle, or diamond. I have this ...
3
votes
1answer
16 views

Deriving coordinates from Application.Display or MxDocument.ActiveView in ArcObjects?

I've found two possible ways of converting a MouseEventsArg's coordinates to the coordinates of the current map: The first is taken from a snippet included with ArcObjects: protected override IPoint ...
1
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0answers
23 views

How to Interpolate very large datasets in QGIS

I am working with a very large set of point data, (XYAttribute) which I wish to display as a raster. I've been using Interpolate, this is successful but very slow. I have other programmes that simply ...
3
votes
1answer
42 views

Find the closest line vertex from the linestring using PostGIS

How to find the closest line vertex from a linestring? ST_ClosestPoint will give a point which is not from the linestring.
2
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1answer
58 views

Representing multiple attributes of single point feature with icons?

I always wondered if there's a way to represent using an array of various icons multiple attributes of a single layer containing point features. For example, think about a point feature with these ...
3
votes
1answer
896 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 ...
1
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1answer
30 views

QGIS 2.4 Layout View pdf/raster file export moves points

I created a map, using a google basemap (openlayer plugin) and imported a table as a csv file (containing a name of a city, latitude, longitude for wgs84 and a row named "amount"). It displays ...
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1answer
169 views

Split a line feature using nearby points

I have a line shapefile and a point shapefile, and the line has its own segments and its attribute table, the point shapefile has points near the line above, not on it and the close ...
4
votes
1answer
222 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
41 views

Delete duplicate polygon nodes with PostGIS

I'm trying to delete duplicate nodes from a shapefile with QGIS, but after running the tool to delete it, nothing happens and shows the same errors. I thought that maybe importing to postgis could be ...
2
votes
1answer
284 views

Postgis 1.4 - Obtain closest point of point over polylines layer (without st_ClosestPoint)

I´ve got a polylines layer (pipes) and a points layer (valves) and In Postgis 1.4 I would like to obtain the closest points but exactly on the closest polyline. In other words, i need to locate each ...
3
votes
2answers
133 views

How to automatically draw lines with a given angle from one single point in qgis 1.8?

I'm new to qgis so please be patient. I need to draw a bundle of lines all originating from the same point and with a 10° angle between each line (e.g. lines bearing at 0,10,20 ..90..110..220..350). I ...
2
votes
1answer
668 views

Getting polygon shapefile node coordinates and point order

I am trying to get the coordinates of each node of a polygon in QGIS. What I basically did is use the following tools: Vector -> Geometry tools -> Extract nodes Vector -> Geometry tools -> Export ...
0
votes
1answer
15 views

ValueError when instantiating LineString from a mix of tuples and Point objects

I'm new to Shapely, and tried instantiating a LineString object from a mix of tuples and Point objects like this: >>> LineString([Point(1,2),(2,3),Point(3,4),(5,5)]) I get the following ...
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1answer
98 views

Get points along a polyline at defined distance c#

I need to store into my array the points along the polyline at each defined distance. Example: The Polyline length is 50m, I set the interval to 5m. I have to store in the array all the points along ...
0
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1answer
30 views

WKT: What is the reasoning behind the concept of a POINT EMPTY?

In data formats like WKT and WKB, we have ways of representing "empty" geometries. That all pretty much makes sense: a "LINESTRING EMPTY" is a LINESTRING type with 0 vertices. Same with a MULTIPOINT, ...
0
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1answer
156 views

How to extend polylines to the nearest point

Hi could anyone tell me a way of getting my polylines to search for a point within a certain number of meters of their start/end points and extend to it? edit: There was some broblem uploading a ...
1
vote
2answers
165 views

Draw line between points from multiple datasets

I have 2 point datasets and want a tool or script to draw a line between all points in one dataset to all the points in the 2nd dataset. Is it possible? I have tried ESRI "Point Distance" and ...
3
votes
2answers
35 views

How to automate drawing a polyline from 2 intersecting datasets based on proximity?

I've been stuck on a situation recently where my company's data has to be integrated with another. Basically there are two point shapefiles comprising of >50000 points, and as shown in the image ...
1
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1answer
88 views

QGIS how to compute a trendline of two point lines?

Does anyone know how to compute a trendline for two lines of points? I have two lines of points of a 10 km long urban road. 1st line is one driving direction and the 2nd line of points ist the other ...
1
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1answer
89 views

What is the best way to display point data (with standard deviation) using QGIS/SAGA/Manifold? [closed]

I would like to display point data values (indicating biomass at a point) but also to show the standard deviation value for each point. What would be the best method to do this in QGIS (I'm a basic ...
0
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0answers
76 views

Point features disappear when moved using QGIS 2.0

When I move, either by the node or the move function, a feature symbol on the map canvas, it simply disappears, not just the label, the whole thing. CTRL-Z brings it back. I'm using a MAC OS-X. I've ...
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0answers
21 views

Creating random location within a network from a given location and a given distance

For a habitat selection study, I am trying to identify availability. My species lives along waterbodies and I could assess distances moved between two consecutive locations using the network analyst ...
0
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1answer
58 views

The best way to convert points to polygons using ArcObjects

I have a set of points from GPS I want to convert them to polygons..I have two approaches to do this.1- convert points to polygon..I do this with below code: private IPolygon ...
3
votes
2answers
110 views

Determining closest representation of polygon as collection of points+radii

Have a bit of a tough question, which I realize there may not be an easy solution to. Figured what better place to ask. I'm attempting to transform a polygon into a series of arbitrary points with ...
2
votes
1answer
136 views

Getting null values using Point sampling tool in QGIS 2.0.1

I would like to obtain the information of a raster layer at some points. Apparently the Point sampling tool does the job. I have used this tool, and all the raster values extracted at specific points ...
0
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0answers
33 views

Reading Points as PolyLines

I'm currently developing an Android app where I need to show some information on a map, which is stored as Shapefiles (.shp + .shx + .dbf). I noticed that when the shapefile is opened in QGis, a nice ...
1
vote
2answers
92 views

Creating density map from point data?

I have point data, where one point represents one 1 storm water outfall, looks like this: (point data is across all of Long Island, New York). I am having a bit of difficulty finding the best tool ...
1
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0answers
20 views

How to compare two sets of points in QGIS?

I have two point layers with XYZ data: 1 set are points measured at the field and the second set is a Lidar data set. I want to check the accuracy of the lidar in comparence to the measured data. Is ...
0
votes
1answer
34 views

TIN file to a POINT file

I have some bathymetry data in TIN format; I am able to open this in arcmap and view the terrain. However I need to use this data within a simulation framework called Delft3D, which needs the ...
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0answers
30 views

QGIS Rasterization of points

I have a point vector layer and want to make it a raster. Trouble is that many points are very close to each other, so unless I specify a very small resolution of the raster cells, likely several ...
2
votes
1answer
60 views

Calculate distance between point and linestring and how to represent that on QGIS?

I have loaded my data with osm2pgrouting and I have my network with ways (Linestring) and nodes (Point). The problem is : I have a database of doctors addresses (point) and I should calculate the ...
8
votes
4answers
1k views

How to view LiDAR data from a web browser?

I am looking to host lidar data on my own server and give clients the ability to view that data through a web browser as a 3D point cloud (file would be in .las format or equivalent), possibly with ...
2
votes
2answers
70 views

QGIS polygon centriods - How are they created?

I have been using QGIS to analyses spatial data and I created polygon centroids with the vector geometry tools. Now for a report I have to explain how these centroids were created. I have not been ...
0
votes
0answers
49 views

how to remove a point or polygon in shapely python

I want to place minimum number of sensors(circles) to cover a maximum area(polygon). I am using "Shapely",python module. I want to know if a sensor i.e a point buffer inside the range of the other ...
0
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2answers
48 views

Adding end nodes to a line

I'm hoping someone can help me here. I have a line feature and what I am trying to achieve is to determine is in which direction the line ends. I understand that this could be achieved with ...
2
votes
4answers
83 views

How to set a minimum point snap distance?

There are two points: A and B. I need to snap any points within a 65 m search radius (blue buffer) of point A. However, the snap distance of B needs to be exactly 5m apart from A (i.e. located ...
1
vote
1answer
85 views

Iterating over all features in featureclass to intersect them individually with polygon using ArcPy?

I've got a point featureclass, and I'm trying to individually intersect each feature with a polygon featureclass to get some information about which polygon each feature is in. I did one intersect ...
1
vote
1answer
33 views

Intersection of two polyline geometries not returning expected coordinates?

T2B = arcpy.Array([arcpy.Point(1,2),arcpy.Point(-1, -2)]) L2R = arcpy.Array([arcpy.Point(0, 2), arcpy.Point(1, -2)]) L2R_line = arcpy.Polyline(L2R) T2B_line = arcpy.Polyline(T2B) cent = ...
1
vote
1answer
61 views

How to analyse point data as covariate for areal data

I have two data sets: a) a set of polygons with areal data variables. b) point measures of various co-variates of interest (note I do not necessarily have a point for each polygon) How do I ...
6
votes
7answers
4k views

Extract raster values at points

How can I extract values from a raster by points. I prefer not in Arcgis. I prefer in Qgis or Mapwindow or other open source gis.
5
votes
0answers
58 views

Point to point and point to line [closed]

I have several points. These points are far from some lines. I want to make the following: If two points are closer to each other than the maximum distance of one of these points to the closest ...
8
votes
2answers
808 views

Creating a line (closest vertex to line)

I am working in reorganising our utility data. Two years ago, we have started collecting Private Service water line. We still have a lot of them to extract from old Record Drawings. I was ...
0
votes
0answers
34 views

Can I create a cross section from points along a line without using a DEM in QGIS?

I have a set of points perpendicular to a river and would like to present a cross section of them. Like a simple graph in Excell for example, with Z as y axis and distance along the line as the x ...
0
votes
1answer
58 views

Density analysis producing extreme values?

I have point data of gas flares and I am trying to create a simple density raster of those flares. Results are either 0 or in the 100,000-1,000,000 range (when there's 5 to 40 or so points in each ...
14
votes
5answers
14k views

How do I create point features with exact coordinates?

How do I create point features with exact (manually entered) coordinates in QGIS? I get precise GPS coordinates from a survey team which I need to add to a point layer. What I want: -Add point, type ...
2
votes
1answer
124 views

Buffers with Varying Distances around a Set of Points

I have set of points in one shapefile and I have a table with a unique identifier that matches each point. I want to make a buffer around each point, according to the radius that I have specified in ...