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

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0answers
64 views

Prediction a point position

I don't know if you could help me in this: I have 7 points (x coordinate is known and variable) (y coordinate is known and fixed) each point represents a position of the same object in a specific ...
1
vote
1answer
509 views

arcpy points in polygon check

I have a list of points and a list of polygons both in a separate shape files. I am trying to write a ArcPy script to loop through the points, and then the polygons respectively and tell me when a ...
2
votes
3answers
689 views

Calculate min distance between points in PostGIS

I have point layer in PostGIS database. Help please with query which add for each points in layer distance in attribute table between this point and another nearest point. Thanks! Update Calculate ...
5
votes
1answer
378 views

How to determine optimal windmill placement to maximize production?

How can I add automatically the maximum number of points (dots) with 6m diameter and 100m distance each point from other into an area. The dots will present the windmill base (6m) and I want the ...
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 ...
6
votes
2answers
694 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
2answers
359 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.
6
votes
3answers
517 views

Classifying point coordinates to countries or continents?

I have about 50 000 points (latitude and longitude), and I would like to find out in which country each of the points is located. It does not need to be super precise, though. (Or actually I only ...
6
votes
3answers
851 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
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 ...
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% ...
9
votes
2answers
1k views

Aggregating points to grid using R

I have a question with regard to spatial aggregation in R. What I am trying to do is aggregate a point dataset to a grid. I am unsure however how to do this as I have little experience with this sort ...
2
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0answers
41 views

Spatial indexing of a point pattern in R [duplicate]

I have a point pattern and a tessellation (grid) in R. Is there a way to spatially index each of my points? In other words, my tessellation grid has n quadrats, I would like to know for each of my ...
0
votes
3answers
300 views

Calculate 'Rectangle' Coordinates Given 2 Points and width [closed]

I want to create a rectangular polygon using two points as guides. So let's say a journey starts in Egypt and ends in London, my polygon should have 4 points: 10 miles further from London than Egypt ...
2
votes
1answer
692 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
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0answers
271 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 ...
0
votes
0answers
54 views

How to format spreadsheet to input point data for later import to PostgreSQL

I want to create a spreadsheet to hold data from our cemetery. I will use the spreadsheet to get the data into a PostgreSQL database. What I dont know yet is the format that the point (positional) ...
6
votes
0answers
227 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
169 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
140 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 ...
7
votes
2answers
165 views

Algorithms for optimally locating points

I am trying to compare locations of where several thousand facilities have been actually built to where they would be optimally located to minimize travel times of the population (represented by ...
3
votes
0answers
209 views

How to Batch Change X, Y Coordinate Number in ArcGIS?

I have a huge number of points (100000 points). Some of these have the same x,y coordinates. For example, 50 points are same in x,y then 100 points are same in another x,y coordinates and so on. ...
6
votes
1answer
224 views

NYC Subway Line Station Order?

I've currently got data on the NYC subway stations (including name, position, and how many people entered and existed during a timeframe). Also, I have the data on which stations have which train ...
4
votes
1answer
990 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 ...
3
votes
3answers
444 views

How to perform a join on simultaneous spatial and attribute criteria in ArcGIS?

I have two point layers and want to perform a spatial join on nearest distance. Normally it is easy with ArcMap. But now I have a restricting condition on the spatial join. The restriction only ...
0
votes
2answers
135 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
41 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
1k 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 ...
2
votes
2answers
1k views

OpenLayers: how to save added point in server side

I'm new in OpenLayers. I have simple application, which use a picture as map, on this picture users can add, move, or delte point, and then save. I have implemented adding, moving, deleting ...
3
votes
1answer
2k views

Creating Isolines from point Data

I'm quite new with ArcGis 10 so I’m having difficulties with something that may be simple to some. Anyway I have a list of bores that I’ve plotted using coordinates. Now I need to draw a single ...
3
votes
1answer
206 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 ...
3
votes
1answer
255 views

How to connect particular sets of points with (poly)lines?

I think my problem is quite easy to be solved by the most postgis-users, but i am a bloody beginner: i have a timestamped point-table representing GPS-tracked places of different cars. To distinguish ...
3
votes
2answers
1k views

Create point to a center of polyline

I'm trying to create a points in the middle of polylines. The data is now in the form of shapefile. Is there an easy way to do this? Cheers, Sanna
4
votes
1answer
349 views

adding multiple points to a linestring in PostGIS

Though a newbie to PostGIS, I'm having trouble solving something that I think should be farily straightforward. I have two linestring tables, both consisting of simple, 2-node line objects: one has ...
7
votes
2answers
572 views

How to add vertices to existing linestrings?

If I have Linestring(1 2, 1 5, 1 9) and a Point(1 3) Is there any function that can merge linestring and point preserving the order so output would be: Linestring(1 2, 1 3, 1 5, 1 9)
4
votes
2answers
368 views

ArcGIS: Rapid digitizing of Point Data

I have several big maps with a lot of points that I have to digitize. All these Points have different Values (depth in Meter, double) and will be stored in 1 Shapefile. Is there a way to speed up my ...
3
votes
1answer
78 views

Plotting pixels on a map image

I've got a list of some hundreds of latitude/longitude pairs close to each other (within a country). I want to create an image with a map, and circles overlaid around these points. Basically, what I ...
0
votes
1answer
199 views

Vector data(point) is drawn in wrong place on map (OpenLayers)

I need to show a map (world map, used default OpenLayers WMS) and one point on it (with events like onhover, etc). Here is my code: var options = { ...
6
votes
1answer
302 views

How to draw shapes with highest possible decimal accuracy

I am trying to read input of lat and long to draw the shape based on condition.The input is standard array of lat and long with 15 decimal accuracy. I am realizing - I am loosing some decimal accuracy ...
3
votes
2answers
2k views

Compute Angle of a line in conventional bearing

I am trying to compute angle between two lines (line segment) using ESRI (ArcGIS, JS) in conventional bearing (Eg: N29'E) I am using Add Toolbar to draw a line segment where point A is a fixed point ...
10
votes
2answers
368 views

How to identify and simplify point clusters with regard to time in PostGIS?

I just started to work with spatial databases and I want to write a SQL(PostGIS) query for automatic generalizing of raw GPS-tracks (with fixed tracking frequency). The first thing I am wokring on is ...
3
votes
2answers
420 views

How to create polyline feature from two input points by following/tracing another polyline?

I have a list of things each have two grid references, start and stop points. I can turn these into points and join them with polylines. But what I need to do is have the lines that join the points ...
4
votes
6answers
2k views

How to represent several points with same coordinates on map?

I'm working on Arcgis 10. I have a point shapefile representing events with several points having coinciding coordinates (They have the same coordinates). For representing them in a dynamic way, I ...
6
votes
2answers
1k views

How can several vector layers have different controls, using Openlayers?

Using openlayers I have two vector layers. One layer is called lineLayer consisting of vector lines, and the other is called pointLayer consisting of points. When I hover on the lines I want to be ...
0
votes
1answer
192 views

What is the fastest way to identify the two nearest linestrings using PostGIS?

I want to be able to identify the closest roads to two points that are generated through geocoding (a start and end address). The points will likely be near a linestring. Two approaches that I have ...
3
votes
1answer
378 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 ...
5
votes
3answers
620 views

Is there a tool to add “noise” to overlapping X, Y coordinates so they are no longer in the EXACT same place?

I have a series of points representing animal observations. Many of them overlap, having the exact same coordinates, and this is causing me trouble when I want to run some analytical tools which ...
4
votes
1answer
2k views

Arcgis 10: Point layer, polygon line layer, draw points to the nearest polygon point or other nearest line?

I have been using arcGIS for a while now but I often get frustrated with it :( I have version 10.0 arcGIS and I'm have two layers 1) Point data (building locations) 2) a polygon shape file (outline ...
4
votes
1answer
599 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 ...
1
vote
1answer
657 views

create buffer around locator-derived point

I am trying to create a buffer around a point derived from a locator search, using this example: http://help.arcgis.com/en/webapi/javascript/arcgis/help/jssamples_start.htm ..but I am getting no ...