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

learn more… | top users | synonyms

3
votes
2answers
107 views

Converting Vertices of Polylines and Polygons to Points and Maintain Attributes

I'm pretty sure someone has done this before, but I'm having no luck. I'm using ArcGIS Standard version 10.2.1 and I want to convert all the vertices of a polyline or polygon to points. Essentially, ...
0
votes
2answers
49 views

Find maximum and minimum value of points within a polygon buffer?

I have a series of 500m buffer zones along a polyline. I also have a series of points following the line, each point represents a 10m x 10m cell. I calculated the values of a field in each point known ...
1
vote
2answers
66 views

How can I group Points to make polygon via Python

I have an array of coordinates Point= [lat,long] ListPoint= [[38.203655,-76.113281],[38.10,-76.12],..] I wanna make a polygon that contains all these points ? There is a project developed by ...
2
votes
1answer
22 views

Using Python to create new point location based on various azimuth and distances

I have a feature class with thousands of points. In the same table with these point locations, I have two additional fields. One for azimuth, and one for a length (or distance) to move along that ...
0
votes
1answer
16 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
0
votes
0answers
23 views

Reducing point numbers in a certain area

We have a list of poi data in our database(Access mdb db), and we have a web service which serve data by a specified BoundingBox. However we found that the returned points are too close to another at ...
2
votes
1answer
27 views

Averaging XY points locations if in close proximity automatically over a large dataset in R

I have a point dataset (XYZ values) containing a few million points covering a 5km x 5km extent representing maxima locations. However there a great deal of these points which exist in 0.5m of others. ...
0
votes
1answer
28 views

Point-sampling rasters using R? [duplicate]

I need to be able to sample many raster files (imported from GeoTIFFs) using a previously defined set of spatial points, using R. What's the best way to do this?
0
votes
0answers
17 views

Pointstack with different count-1-symbols / SLD / GeoServer

I try to use the pointstack sld to visualize my data at different scales. I used the example from http://suite.opengeo.org/opengeo-docs/cartography/rt/pointstacker.html, and everything is fine. ...
0
votes
1answer
101 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
votes
0answers
35 views

How to create a point representing a polyline?

How do I convert a line (usually 2 vertices but can be more) into a single point in QGIS? I did it a couple of years ago using a build-in tool in ArcGIS 8 or 9 I think but have no idea how to do it in ...
1
vote
2answers
77 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 ...
6
votes
1answer
140 views

How can I transform polylines into points every n metres in PostGIS?

Question in pretty much the same as this, but I need to use PostGIS. I have a number of polylines, and want to trasform them into points every n metres along these lines. edit: Thanks a lot to ...
1
vote
2answers
93 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 ...
1
vote
2answers
31 views

Creating Many Uneven Buffers

Qgis 2.2, Windows 7 I am looking to create buffers around city lights (the raster). Currently, I have simple polygon buffers around the point layer (oecdminusa), but this is not accurately capturing ...
0
votes
0answers
15 views

Point in Linefeature build through specific topology rules

i want to build Lines from Point Features following different topology rules (that lines aren't like randomly build, but how i should be following the extent from other polygons for example.. when ...
0
votes
1answer
26 views

Creating points based on coordinates in MapBasic

I am currently working on a MapBasic tool that generates start and end coordinates for a polyline layer. So far I have successfully populated 4 columns in a table (SX, EX, SY, EX) with coordinates of ...
2
votes
1answer
393 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 ...
4
votes
2answers
4k 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 ...
11
votes
3answers
4k 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 ...
2
votes
1answer
228 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 ...
4
votes
2answers
108 views

How to speed up a query for nearest linestring to point data

I have processed a Strahler stream order layer with a lot of river linestrings (type: Multilinestring) and their corresponding strahler number (see information here). Besides I have a point layer. I ...
4
votes
1answer
191 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 ...
1
vote
1answer
112 views

Compare field values and assign a new field to store value ArcMap 10 python

I am currently doing an analysis in Arc Map 10 using python, as I am not familiar with this tool, hence I come here to ask your help. I actually have two shape layers, one is a point layer and the ...
5
votes
1answer
768 views

Problems converting polygon to point

I'm trying to convert polygons to points with ArcGIS 10. My polygon layer has 2 attributes that I want to give to my point layer. I'm using the Feature to Point function from the Arctoolbox, but it ...
4
votes
1answer
53 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
2answers
88 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 ...
0
votes
2answers
70 views

GeoServer create layer from PostGIS (data type point)

(Several days ago a user on gis stackexchange suggest that I should use OpenGeo (I was using geojson before). I succeed at what I was doing at that time, but now I have a different problem.) I was ...
3
votes
1answer
63 views

polygon from exterior points

How to convert points data to polygon, so as to form polygon from exterior point as shown above
0
votes
2answers
128 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
vote
1answer
65 views

Counting points in a raster

Is there a way to select points in a raster dataset by raster classification? I have a floating point raster created from the points, classified into 4 ranges by standard deviation. I want to find out ...
0
votes
1answer
92 views

Geodjango: Using Lat / Lon to Buffer from Point

I want to have a radius based distance search. To do this, I want to create a buffer around a point object so that I can filter objects that are inside this buffer, a method that I learned based on a ...
0
votes
0answers
23 views

Multiple Centroids within a dataset based on distance

Is there a way that we can find out the centroids of clusters within a dataset while differentiating one cluster from other based on distance not on any attribute value. The dataset is present in ...
0
votes
2answers
209 views

Using NetCDF for point time-series observations?

I have a large growing dataset of water and climate observations for several years in regular hourly time-step. The number of locations is cca. 1000 locations with latitude, longitude coordinates. At ...
1
vote
2answers
58 views

Finding routes in which more than one car passed (gps data)

I'm using ArcGIS 10.1. I have point GPS data of routes of several cars over a few days, and I want to find only the routes where more than one or two different cars passed through (Each GPS points ...
0
votes
0answers
13 views

Can't get X coordinate of PointM in PostGIS

Here are two queries, and I can't understand how to filter points if st_x does not work in WHERE clause. select st_x(geom_merk), st_asewkt(geom_merk) from road_density limit 5; ...
1
vote
2answers
54 views

QGIS 2.0 Automatic generation of a vector layer out of a point layer

I am an environmental engineer and the aim of my QGIS 2.0 project is to visualize the results of a sewage water system inspection. In a first step I included the hoppers from a csv file and added a ...
0
votes
1answer
32 views

Get all points with in some range of a point (or range of point)

I have got a list of points and a fixed range (10m). So what I have to do is for each point I have to find all the points present in a table with the 10m range of the given point. For example: Let ...
0
votes
2answers
48 views

How to get information about only one data point?

I have a vector-point shapefile. The data are not dense (about 1 x 1 degree). Lets say that every point includes value of average wind speed. I would like to create a interactive web-map so that ...
1
vote
1answer
45 views

Identify geographic location to points

I am quite new in QGIS and I really need your help. I have a map of Kenya divided into 68 districts and I have coordinates of 30.000 schools. The points have one variable besides the latitude and ...
1
vote
1answer
41 views

Adding XY coordinates from a point feature class to a one to many related table in ArcGIS 10.0

I have a point feature class with a one-to-many relate to a table. I would like to add the XY coordinates of each point in the feature class to the related table where the ID field matches. Of course, ...
3
votes
1answer
115 views

Select points approx. 2000 metres from another point along a river?

I have a series of points representing a river network (See Image Above). Each point contains attributes on Latitude, Longitude, Z value and Length calculated using flow accumulation. The river ...
5
votes
1answer
150 views

How many GIS projects deal with just basic “putting markers on a map”?

Is there an academic paper or conference contribution, where someone estimated how many GIS projects actually deal with only a very basic usage of GIS data? Something equivalent to the infamous "80% ...
0
votes
0answers
25 views

Creating a point layer from lat/long coordinates [duplicate]

I have a spreadsheet that lists the lat/long coordinates of several locations I wish to map. I would like to produce a geocoded point layer in QGIS. How do I do this? Thanks!
1
vote
1answer
111 views

Problem creating point shapefiles programmatically using python in QGIS 2.2

I am trying to create a point shapefile in the memory buffer (for a temporary label) and then zoom to the extents on this buffer. The working (in version 2.1) test code for this is: def ...
2
votes
1answer
38 views

How to find the polyline's ID connecting two points in ArcGIS 10.1?

I have an ArcMap (*.mxd) file with several layers including a point layer and a polyline layer. The points are connected by polylines in the polyline layer, and I wish to know how to list the ...
2
votes
0answers
40 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 ...
0
votes
3answers
68 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
votes
1answer
60 views

How to calculate distances between several points along network?

I have several points (bicycle share hubs), and I want to calculate the distance between each of them using a network. I want a CSV/XLS that has three headers: hub_id1, hub_id2, distance. I've ...
1
vote
2answers
76 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 ...