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

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2answers
158 views

How to get an indication of how points are spatially distributed?

Let's say I have a set of points and I want to get an indication of their spatial distribution. That is, if all points are at one location a possible return value would be 0, whereas if all points are ...
0
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1answer
11 views

GRASS Add Vector Point

I need to do a viewshed analysis using GRASS. I've got the DEMs loaded; and I simply want to input several (2-4) points (like 41.12345N, 122.34567W from GPS). What is the simplest, most ...
1
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2answers
119 views

Create line between polygon and nearest raster cell

I need to create a line between polygons (centroid) and the nearest cell of a raster dataset. The polygon and raster do not intersect. Each polygon has a UID. One cell can be linked to many polygons, ...
1
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1answer
55 views

Python script to select a point within a cell?

I have two features: points and grid cells (vector). I want to select a point within a grid cell (some cell do not have point) using python script and create a new feature layer with below conditions: ...
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3answers
352 views

splitting a lines layer using points

I'm looking to accomplish a similar task to this thread: How to split a line at point positions? Using QGIS and the Processing and GRASS toolboxes available, I'm looking to split a vector layer ...
3
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0answers
86 views

Find the co-ordinates of tangent points and intersection of a curved line [closed]

I have a line with curves in it. Is there an easy way to extract the X Y values for the tangent points and intersection points in ArcMap 10.2.1? Hopefully my simple paint diagram clarifies what I ...
0
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1answer
73 views

Can I use Point as the geom type in pgrouting?

in my table i have the field geom(POINT, srid) and its populated, this table also have the source an target field witch is blank(just like pgrouting guide). I tried the function pgr_createTopology() ...
2
votes
4answers
169 views

Linking up GPS points taken from rail network

Bit of a newbie here, trying to work out whether any PostGIS functions can help with my task. Apologies in advance if my use of GIS terminology is not up to scratch yet. I have a large database of ...
3
votes
2answers
326 views

Line start and end nodes: determining what is a junction

I have a layer of points and polylines and want to determine which points are road junctions. I currently have all start and end nodes within 3m of my road network as a layer. However I cannot ...
2
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0answers
47 views

What is an Orphan point?

MY apologizes about the next doubt, but I can't understand what is an orphan point. I am using QGIS with a module to apply the Linear Reference System (the module is called "LRS"). During the ...
4
votes
1answer
228 views

Create a point at the highest value in a raster ArcGIS 10.1

I am trying to find the location of the highest value pixel in my Direct Solar Radiation Raster. I can see the extent of the data in my raster but don't know where the highest value pertains to. Is ...
3
votes
1answer
104 views

How to map flood areas from a set of points containing surface and height of water?

I am working on the damages made by the typhoon Haiyan. I use QGIS 2.0 with extensions and toolbox, and MapInfo. I have vectors, rasters of the place. I want to map the flood area along the ...
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0answers
32 views

Creating contours from partial data set

Is it possible to create contour lines based on part of the points and not the entire dataset?
2
votes
1answer
203 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 ...
3
votes
1answer
143 views

How to horizontally align irregularly shaped point symbol to vector layer in QGIS?

Fairly new to QGIS and searching a method to graphically align my point symbols in the direction of the vector. The symbol represents a water valve in an irregular shape in close proximity to a vector ...
1
vote
2answers
97 views

Find nearest point (in file A) for every point (in file B)

I have 2 csv files both with 3 columns: variable, lat, lon. Let's call them file A and file B. File A has 100 values for variable (in this case city), File B has 100,000 values for variable (station ...
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0answers
56 views

Geoserver-WMS-problem when zooming point layer

I need help. I would like to have no blank(white) space between points when zooming in WMS geoserver. Any idea? Greetings, Andrew
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1answer
85 views

Can I “undo” buffering of a point layer in QGIS?

I have point layer, where each point is one tree, about 1300 trees in total. I made buffers around each tree, the buffer being the height of each tree in QGIS 2.0.1. My next step was to use Spatial ...
2
votes
3answers
502 views

Can ArcGIS only merge two shapefiles each time?

I need to merge multiple point shapefiles (in the same directory) into one point shapefile. After inputting these shapefiles and merging it, I found the final output only contained the data from two ...
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2answers
347 views

TIFF/Raster to Point shapefile question

Apologies in advance if this question is incredibly basic, but I've been googling around and I just don't know where to start. I've downloaded some nighttime luminosity data from NASA, and the data ...
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2answers
195 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 ...
0
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0answers
85 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 ...
5
votes
3answers
328 views

How to visually sort the order of Points with QGIS, GDAL, …?

The following Points layer is the basis of a rendering in a Android application. Android allows to draw a shape from the provided points. I cannot use LineStrings. However, the order of points ...
2
votes
2answers
179 views

How to convert Point coordinates into CSV format?

The GDAL documentation describes how to convert a ShapeFile into CSV data. The layer create options (-lco parameter) allows to prepend the coordinates of Point features to the actual attributes ...
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2answers
88 views

What is the most efficient method to delete points?

I have a script that takes a point featureclass (FC) through the following workflow: Select points that lie within individual polygons From the selected points within each polygon, randomly subset ...
1
vote
1answer
121 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 ...
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0answers
109 views

How to change icon symbols in QGIS? Can icons have JavaScript animations?

There are a lot of SVG files located in the "QGIS Dufour" Program Files folder on my PC. I was thinking that I could find the symbol that I want to change in the GUI in this listing in InkScape so I ...
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0answers
119 views

Building real-time point/polyline connection in GIS

In the first instance I need to create the network by constructing the basic elements, the nodes and links. This is relatively easy work as SharpMap has provided geometry tools that allow users to ...
0
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2answers
272 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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1answer
132 views

QGIS how to compute a trendline of two point lines? [on hold]

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 ...
2
votes
1answer
35 views

Get coodinates from point shapefile

I converted a line shapefile to points as you can see in the attached image. Is there a way to know the coordinates of each point? Any help would be really appreciated! PD Im using QGIS 1.8.0
4
votes
4answers
2k views

How to randomly subset X% of selected points?

What methods are available in ArcGIS 10.2 to randomly subset a selection of points. For example, in the attached screenshot I am interested in keeping 20% of the selected points and deleting the ...
0
votes
1answer
158 views

Defining a WHERE clause from a subquery for a query to create a handy view

It is about my implementation from an answer of this question. It is more an postgresql issue than a GIS issue, whereas it is about geometries and spatial queries. I want to create a view from the ...
2
votes
0answers
108 views

(Solved) Near/Spatial Join pick the wrong polyline segment as closest [closed]

I have a set of points near a street centerline. I need to find the perpendicular point on the street centerline, and use their x y instead of the GPS information of the original points. I tried Near ...
8
votes
4answers
2k 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 ...
1
vote
2answers
193 views

Alternative to ST_ClosestPoint, one which returns a vertex of the geometry

ST_ClosestPoint returns the closest point on a geometry, as in the example at http://postgis.net/docs/ST_ClosestPoint.html What I need is to get the closest point which is already a part of the ...
0
votes
1answer
196 views

How to display coordinates of a point in a projected cooridante system?

I want to check the coordinates of a point. On selecting this point in ArcGIS it displays a latitude and Longitude . In ArcGIS I found an option in 'Identity Tool' that the Latitude and Longitude ...
2
votes
2answers
145 views

Creating a circle with points

I want to arrange 96 points as a circle/ring. Is there a way to make this automatically, for example "Buffer", "vertices"...? Kind regards, Stefan
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0answers
63 views

How to auto-fill a new point vector in a vector layer?

When I work in-situ I manually add points in my shape-file. I would like that when I add a new point some attributes would already filled with values calculated programmatically. E.g in my first ...
0
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1answer
63 views

QGIS proximity raster with extent beyond original coverage?

I need a raster coverage of distances from points outside the geographic region of interest, and am having trouble doing this with QGIS. Questions like this one (Calculating distance to points in ...
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0answers
31 views

QGIS rule-based point style responding to number of co-located objects?

I am mapping the geolocated location information for 5.5k Twitter profiles as point data. Many of them have the same location ie "London, UK" meaning that they return identical coordinates. On the map ...
4
votes
1answer
80 views

How to find closest point without crossing obstacles?

I have a set of points and I'd like to be able to find the nearest point from another layer. The problem is that I need to find the closest point without crossing an obstacle (such as a river, ...
2
votes
1answer
232 views

Moving a shapefile point to specific coordinates

In QGIS is there a simple way to move a shapefile point in a shapefile point file to specific coordinates? Without exporting the points to WKT changing the x,y values and then importing the WKT via ...
4
votes
1answer
554 views

How to create linestrings with a definite angle and length, that are fixed to a point

I want to create linestrings with a definite angle (e.g. 160°) and length (e.g. 2m) that are fixed to a number of points of another linestring. So, I want to use the ST_DumpPoints function to find the ...
0
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0answers
26 views

How to divide my area into adjecent polygons containing 80 points each? [duplicate]

I have a couple of thousand points in my dataset. I need to create clusters that each consists of 80 points. The specific selection of which points to put into a cluster is not critical - only the ...
3
votes
1answer
64 views

Exploratory search for clusters in point data

This is a more conceptual than practical question and is about exploratory cluster identification. While there are very specific meanings in the geography canon as to what they are, in economics they ...
1
vote
1answer
71 views

why are my buffers not lining up with their original points despite setting the layer crs as all the same crs when I reopen my project [closed]

I am having my entire project in pseduo mercator (google earth raster image) and when I create buffers for points and then open back up my project all the buffers are offset from their points. ...
1
vote
2answers
343 views

Extract a LineString from LineString by two Points

I am using PostGIS2.0 and PostgreSQL9.3. I have LineString in Spatial-Ref 4326 like geom:= ST_GEOMETRYFROMTEXT('LINESTRING(60.7014631515719 56.8441322356241,60.7023117507097 ...
4
votes
1answer
429 views

Calculate distance to median point for a group of points in ArcGIS 10.1

I have a shapefile called "household_points" of ~2,000 points, which are divided into about 100 sites. The shapefile has a field in the attribute table called "SNAME" and in the field each point is ...
2
votes
0answers
47 views

Update PG table setting an area_id

I have a table with lots of points which I'd like to update and set a consecutive area_id to every point "group". I define a point "group" as points that are within a 500 meters radius. The raw table ...