A geometric element defined by a pair of x,y coordinates.
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 ...
6
votes
2answers
186 views
Why am I getting duplicate ghost points (features), i.e., one point in the feature class but two points?
When editing some of the attributes in a point feature class in ArcMap 9.3, duplicate labels started showing up. When I click on the point, I discovered that the point has duplicated itself BUT there ...
0
votes
0answers
71 views
Can I write a query in MapInfo to select points within a certain distance of each other?
Example: I have 400 points. I want to make 4 different groups (roughly 100 points each) and I want the groups to contain the points that are closest, spatially, to one another.
1
vote
0answers
44 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
147 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
2answers
195 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 ...
6
votes
3answers
221 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 ...
0
votes
0answers
47 views
How to Draw a Point on a Geotiff in Android and Put it in the Postgresql Database?
I need to:
Open a geotiff in my phone (android) {offline)
Draw a point
Get it's coordinates (X,Y)
Fill in the data attributes (name of the point, ...)
Put the data and the coordinates in my ...
13
votes
4answers
795 views
algorithm to place maximum number of points within constrained area at a minimum spacing
I have a polygon layer that describes a constraint; I wish to add points within this area. I want to add as many points as possible, but they must have a minimum spacing between them. Is it possible ...
3
votes
1answer
185 views
Estimating cline width at multiple points along a trait gradient
In the map below I have 66 (green) points along the midpoint (0.5) for an allele frequency cline across the region (see map). I created the points by placing a point every 25 km along the 0.5 allele ...
10
votes
2answers
204 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 ...
5
votes
1answer
183 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 ...
3
votes
2answers
322 views
How to extract cell values from a raster file with Idrisi Taiga?
I need to convert raster cells into points. I use Idrisi and I need to generate a table containing xy (coordinates) and z (cell value).
5
votes
1answer
226 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
214 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 ...
6
votes
1answer
104 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% ...
7
votes
2answers
274 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 ...
0
votes
3answers
214 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
0answers
40 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 ...
2
votes
1answer
158 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
92 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
43 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) ...
3
votes
1answer
99 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 ...
4
votes
4answers
335 views
How to sample raster datasets at ALL points?
I know it is possible to use tools like ArcGis's 'extract sample' tool to extract values at a given number of points. I would like to sample every pixel in a raster, and drill down through all other ...
5
votes
0answers
93 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 ...
19
votes
6answers
2k views
How to compare two spatial point patterns?
If I have two point pattern distributions within the same geographic region, how would I go about visually and quantitatively comparing those two distributions?
Also assume I have many points within ...
5
votes
2answers
94 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 ...
2
votes
1answer
229 views
How to move a Point perpendicular from nearest Line?
I want to move Point perpendicular from nearest line or polygon, and the question is how to do that?
example, I have points (house number) near roadbed, and I don't want them to intersect roadbed ...
6
votes
2answers
112 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 ...
0
votes
0answers
22 views
How to export Dispers Markers result?
I have many points in same x,y . i'd like to show , select by attribute and location . The result of disperse markres is a representation . It just show points and not save all of them in desired ...
3
votes
0answers
149 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. ...
3
votes
3answers
203 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 ...
4
votes
1answer
260 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
83 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
198 views
How to display points on map as a graphic using C#?
I have created map using ArcGIS Server in C#. I need to display points as a graphic.
my database consists of points lat lon values,
xval yval txnid attr1 attr2
...
0
votes
0answers
30 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
249 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 ...
1
vote
2answers
233 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
113 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
347 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
113 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 ...
2
votes
2answers
333 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
198 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
4answers
2k views
Get all the points of a polyline
I have some polyline feature objects in python. Now I want to get all the points of polylines.
For example, if a polyline has start point [0,0] end point [5,5].
Result: ...
6
votes
2answers
177 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
208 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
62 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
104 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
193 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 ...
