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

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4answers
429 views

How to find the center point of MULTILINESTRING?

How to find the center point of MULTILINESTRING, which lies on the multiline?
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0answers
100 views

Esri ArcGIS plot point

I have created a java function to plot the points on the map, and I need to pass the x-y coordinates and the taskevent as the parameters. I would like to ask what should be the input parameter for ...
2
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1answer
288 views

How to find the nearest single point?

I have two shapefiles containing each one set of points, set A and set B. One set is my random selection (set A), the other is a list of communities (set B). For each point of the random selection ...
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2answers
1k views

How to offset point perpendicular to line direction in PostGIS

I have a postgis table of points, that are sitting on road centerlines (I've linear referenced them). And the second table with road centerlines themselves. The point table also has a field roadid and ...
0
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0answers
423 views

How to do a spatial join if QGIS 1.8 keeps crashing?

I am trying to perform a simple spatial join (adding polygon data to points) in QGIS 1.8: target vector: points join vector: polygons take attributes of first located feature keep all records ...
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2answers
1k views

PostGIS convert geography(Point,4326) to GPS

I got a database with a column of type geography(Point,4326), the data contained looks like 0101000020E610000092E057F66EF73140930035B56CBD4840. How can I convert it to GPS coordinates?
5
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1answer
173 views

Given 2 LINESTRINGs with common point, how to extract common point?

I have 2 LINESTRING geometries. I know both share a common point. Using PostGIS for Postgres, what is the cleanest way to extract the common point? Example with illustration: How do I extract the ...
2
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1answer
322 views

How to create a point table from a remote csv file?

The current approach that I am using to load a csv file into a PostGIS enabled database on a server is the following: -- create table CREATE TABLE points( id int, lat double precision, lng double ...
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1answer
481 views

Is it possible to create a point within a Polygon (not a centroid)?

Is it possible (without writing Python code - sorry I'm not a developer) to create a point layer from a polygon layer but ensure the point is within the polygon? The ftools centroid tool is cool but ...
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2answers
4k views

How to calculate new point coordinates from distance and angle?

I want to calculate the coordinates of a new point. What I have: The source point coordinates, the distance (meters) and the angle For example: I want to create a point within 100 meters and 45 ...
5
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3answers
3k views

How do I retrieve start and end point coordinates with Python/arcpy?

How do I retrieve start and end point coordinates with Python/arcpy for a polyline feature class? I expect to pass a segment identifier to a subroutine and have it pass back start and end coordinates. ...
0
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2answers
465 views

Handling points in openlayers

I have a several hundred points that I am showing on a map. At the moment, my method of adding the points seems inefficient. I create an array using the following approach: var features = [new ...
2
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0answers
459 views

cant find point/polygon intersect using qgis (windows only)

below i describe the method i am using. i have 2 machines: 1 ubuntu linux, qgis 1.4 - intersection works 2 WIN xp, qgis 1.8 - intersection dows not work hopefully, someone will ...
6
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2answers
237 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 ...
8
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4answers
1k views

How to filter wrong GPS points?

I have a database of GPS points. There aren't any tracks, only points. I need to calculate some value for every 100 meters, but sometimes GPS gave a wrong coordinates that lies far from real GPS ...
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1answer
419 views

Generating Point from Centroid of Polygon Error

I have a feature class of polygons within a geodatabase and I'm trying to generate points based on the centroid of the polygon using the Feature to Point tool in ArcGIS 9.3. However, I end up with ...
8
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2answers
896 views

How can I create random points along a polyline in QGIS?

I am trying to create random points along a polyline shapefile in QGIS. Basically, like the 'random points' tool in 'research tools' but for polylines instead of polygons. I have tried converting ...
3
votes
2answers
895 views

How can i select a polygon in MS SQL 2008

I am very new to MS SQL 2008. I got a task to select a polygon from the polygon layer by giving the X-Y coordinates. I already got the script for PostgreSQL for the same thing, but i need it for MS ...
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4answers
3k views

Prevent drawing of overlapping point symbols - ArcGIS Server/Javascript API

Is there any way in ArcGIS to prevent symbols from being drawn when they overlap each other? I know this is possible for Labels using Placement Properties/Label Weight, but I can't seem to find ...
2
votes
2answers
406 views

Where can I get a multipoint shapefile?

I'm trying to find a multipoint shapefile to do some testing for an application I'm working on, but I cannot seem to find one (and do not have ArcGIS to create one). Can anyone suggest a place to find ...
2
votes
1answer
689 views

Geometryutil, simplify polygon, querytask and query fault error

One of the tools in my app is to draw freehand polygons (counties) to show points (companies) in each county. Everything works great but if the user creates an intersecting polygon then I have a ...
1
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3answers
484 views

Divide Line Into Sections Using Points Offset from It

I have track (line) and milemarkers (point). Each point is offset by a different distance. Is there a way to find where each point would intersect the line if going perpeniduclarly out from the line? ...
3
votes
2answers
1k views

Update point coordinates in QGIS after manually moving locations in edit mode

I have imported point coordinates from a database, but I need to manually adjust a lot of the locations. Is there a way for QGIS to automatically update the point locations in the attribute table ...
4
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1answer
431 views

Address or reverse geocode a point shapefile

I have a shape file that contains points. I want to do a reverse geocode and give these points an address. Can someone please help me?
3
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0answers
70 views

Adding points to represent non-chosen locations

I am looking for a way to set up a discrete choice model in ArcGIS for foraging behavior of individuals, in a grid of 15 locations. To do that I need a point for every possible choice they could have ...
4
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5answers
4k views

How do I create a line between two points with a common field?

Does anyone know how I could create a line between two points that have a common code? For example: I have the start and end point of a pipe as a lat/long for a network of pipes, each with a ...
7
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3answers
611 views

Creating raster or vector raster from DEM point file?

i have a point shape of 75.000 elevation points in a regular 5 m grid. We now want to create a polygon grid with the elevation points as "centroids". Unfortunately, all attempts to do so fail: I ...
4
votes
4answers
530 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 ...
2
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0answers
129 views

How does integrate work with point data sets?

I'm trying to combine point data into clusters and I think I've come up with a method that will work for what I want to accomplish. However, I don't understand why it works the way it does and I'm ...
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1answer
90 views

Anyone know where I can find a file like this for Pakistan?

Can anyone tell me where I can find a file like this on Pakistan? I found it on ochaonline.un.org I cannot find it when I search on there. ...
3
votes
1answer
2k views

convert list of points to line or polygon

I have a list of Points in a PostGIS table. The rows can be grouped by a date something like: myTable id INT date DATE lat NUMBER lng NUMBER geom GEOMETRY(POINT) now I need a table where all ...
7
votes
4answers
4k 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: ...
3
votes
2answers
1k views

ArcGIS 10: How to clip point buffer to features in another layer?

I'm on a steep learnig curve here, so aplogies if my question is a one-banana problem. In ArcGIS 10 I have a contour layer that was generated from an ESR ASCII raster file (batyhmetry of the South ...
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1answer
346 views

PostGIS - table with 3d points with fast ordering by distance

I am pretty new to PostGIS and I am trying to solve the following problem. I need a table with 3D points (x,y,z) that will contain around 1-10million points. I want to be able to efficiently ask the ...
9
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1answer
508 views

How much sense does it make to average (lat,lon) samples in order to increase 2D accuracy of a GPS location?

Several GPS applications, like this one, or this one, acquire multiple (lat,lon) samples of a given location, assuming that the GPS unit is not moving, and then take an average of the samples in order ...
1
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1answer
154 views

QGIS - WGS84 to BC Albers reprojection no curved lines, any idea why? How to snap a line to a point?

I am trying to learn a bit about QGIS. So I thought I would drop in some layers of my Province and then recreate some points representing the BC Albers Central Meridian, and the two standard ...
3
votes
1answer
2k views

QGIS calculate distance of point along a line

I have a polyline (movement path) and points recorded along the line. I would like to calculate for each point the distance along the line in Quantum GIS. I hope for a result which will add a new ...
3
votes
2answers
733 views

From point to Grid of polygones or polylines

Is it possible to reconstruct a grid of polygones or polylines from the centroids? I am looking for a arcGIS tool or script that will allow me to reconstruct a grid of polygons or polylines from ...
2
votes
3answers
832 views

Accessing coordinates of polygon

I have designed a polygon in a web page and the coordinates are stored in the database of the type polygon. However when I check the database, I find GEOMETRY - 120B under polygon field. What does ...
3
votes
1answer
233 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 ...
6
votes
4answers
4k views

How do I convert a polygon into a point?

I want to convert polygons into points. I know how it's done in ArcGis and I think this may sound trivial but it's a serious issue :/. I'll appreciate any hints :)
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0answers
245 views

Create IPoint with Lat/Long in decimal degrees and Z in feet

I have written an ArcMap v10 AddIn that reads a folder of geotagged JPEG's and creates a new feature class where each point is the geotag information from on of the JPEG's. The issue is: The GPS ...
7
votes
4answers
823 views

Output PostGIS geometry data as centroid or polygon depending on zoom level (GeoServer)

This is what I want: when I zoom out, cities of the country should appear as points and at a certain level when I zoom in, I want them to appear as polygons (showing the area of the city and ...
2
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1answer
2k views

How to add points to a point vector layer - QGIS

I have a point layer with multiple data points in QGIS, but I want to add some extra data points to it and adjust some info that we missed because the ground was wet and we needed to go around it. I ...
3
votes
1answer
645 views

OpenLayers Point Feature Vanish on Zoom-In

I use OpenLayers to animate a point moving along a line. To do this I use several map layers and one vector layer to contain one LineString feature and one Point feature. Currently, the animation is ...
2
votes
1answer
327 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 ...
3
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2answers
455 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).
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2answers
402 views

How to modifiy how selection highlights are displayed? [closed]

I have got a layer of points that are showed with a litlle symbol. When I select one, a red square comes around it. The problem is that this points are inside other layers (polygons) and some of them ...
3
votes
2answers
336 views

Housenumber(point) angle from line (street)

using arcgis 10 with Point data (Housenumber without angle attribute) and line data (street without angle attribute) I want to create housenumber labels from point with correct angle from nearest ...
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0answers
266 views

ArcGIS10 Split Line at Point Failing due to Dataset size

Im having an Issue with my Split Line at Point tool. Seems to run if lucky for 700 entries before arcmap/arccatalog falls over. Debugging of the errorlog has produced nothing. The total size of the ...