Questions tagged [point]

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

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votes
2answers
139 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. http://www.scribd.com/doc/38714310/Afghanistan-Settlements-...
3
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1answer
7k 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 ...
10
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4answers
16k 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: [1,1];[2,2];[3,3];[4,4];[5,5]...
3
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2answers
3k 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 ...
5
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1answer
1k 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 ...
23
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2answers
8k 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
233 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 ...
12
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3answers
9k 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
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2answers
4k 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
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3answers
3k 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 ...
4
votes
1answer
347 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 ...
17
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4answers
23k views

Converting Polygon into single or all Points using QGIS?

I want to convert polygons into points using QGIS. I know how it's done in ArcGIS Desktop.
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0answers
505 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
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4answers
2k 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 ...
6
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2answers
40k views

Adding points to point vector layer using 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
1k 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
882 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 (...
2
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2answers
1k 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).
4
votes
1answer
7k views

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

I have got a layer of points that are showed with a little symbol. When I select one, a red square comes around it. The problem is that these points are inside other layers (polygons) and some of them ...
3
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2answers
564 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 ...
16
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1answer
10k views

Calculating distance to points in QGIS

Is there a way of calculating the distance to the nearest points in QGIS? In ArcGIS there is a function called Euclidean Distance, which can take an input vector or raster, and generate a raster of ...
2
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0answers
289 views

Updating SDE point feature classes with SQL SERVER 2008 R2 [closed]

I am contacting you in hope that you can help me resolve an issue using SQL Server 2008 R2 to push updates to a SDE point feature class. We are using a C# app that uses ArcGIS Runtime to edit the ...
4
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3answers
7k views

OpenLayers: Showing a WFS overlay on top of Google Maps

I have found similar questions asked previously, but I still fail to get a simple WFS point layer to work using OpenLayers and Google Maps. The original code I used was based on WFS polygon layers I ...
5
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2answers
13k views

What are units of Distance Matrix tool results 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 ...
7
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2answers
1k views

How to create zip code areas from point data?

I have a point dataset which has zipcodes for a certain region. This zipcodes have been marked on the basis of lat long collected. So each zipcode is repeated as it would be useful to show the region ...
11
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5answers
26k views

Creating polygons around extent of similar points using ArcGIS Desktop?

I've millions of points collected for lithology layer. They have used a coding for different types of rocks. I need to create a polygon around the extent of similar points. What is the easiest ...
2
votes
2answers
831 views

Setting up drawing order for point shapefile

I am having a difficulty with creating polyline feature from a point dataset that represents a boundary. This dataset consists of 5084 points which are randomly ordered. I have no Network Analyst ...
11
votes
1answer
18k views

Simple PostGIS ST_Distance query for two points from the same geometry table?

Note: This question was published at Stackoverflow at first. I have a geometry table points_table with SRID 4326 and a few points in it. I need to find a distance between a pair of points (features) ...
2
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3answers
2k views

How to create a efficent linestring out of geography points using postgis

I'm trying to create a linestring out of geography points. At the moment I'm doing it like this: select ST_GeographyFromText(ST_Makeline(a.record_point)) from ( select (record_point::geometry) from ...
3
votes
2answers
1k views

Total great circle distance along a path of points

I am looking for an SQL query that sums the distances between a series of points using PostGIS. The situation is as follows: I have 2 tables: tracks and points. Points belong to a track and thus ...
2
votes
2answers
4k views

How to create a graphic point by xy value?

I have implemented this code to create point event layer by xy text file, however I'm wondering how to create a point graphic by xy value? This script draws point graphic by mouse down. When I steer ...
6
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1answer
24k views

Create point in intersections of two layers

I have two layers. One of them is 'Road_line' and another one is 'forest_shape'. I want to create a point layer that has points in intersection of that layers. I couldn't find any tools for it.
8
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2answers
16k views

How to find nearest point for each point in current layer using ArcGIS Desktop?

I have a point layer and want to know the distance of nearest point of current layer for each point in the layer. I found some tools in ArcToolbox about it , but they need two layers for input and ...
11
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2answers
2k views

Creating line (closest vertex to line) using ArcGIS Desktop?

I'm using ArcInfo 10 SP3. I am working in reorganising our utility data. Two years ago, we have started collecting Private Service water line. We still have a lot of them to extract from old ...
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0answers
89 views

Point features disappear when adding new data

Recently while adding features to a point layer i noticed that once i had saved my edits the already existing points disappeared. Although not visable on the map all of them and their data were still ...
0
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2answers
2k views

Is there a way to have a single point feature with multiple records?

Is there a way to have a single point feature and have multiple attributes records associated with it? Multipoint approach won't work as it gives me one attribute set (database row). I am trying to ...
3
votes
2answers
5k views

How to easily enter a point feature in ArcGIS? (arcmap10)

My job requires me to enter point features into ArcGIS 10 which correlate to underground RFID markers that mark underground telecom infrastructure. Right now, the workflow requires someone to go out, ...
2
votes
2answers
3k views

How to automate point-in-polygon queries in ArcView?

Layer1 = point shapefile (multiple points, geocoded) Layer2 = polygon (1 attribute; (1,2,3...)) I want a non-gis person to be able input a single address and be told the attribute of the polygon ...
3
votes
2answers
1k views

How to loop through an array of point features?

I have a set of point features and I wish to find the points that have common coordinates. Now I changed the code as shwon bewlo by using the IPoint and the compare method through a function. I have 2 ...
1
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0answers
458 views

Moving GPS Points with a VB script - Bearing works well but distance is wrong

I am using a script I found online created in 2003 by one of the commentators here. It is a great script and exactly what I have been looking for and I'm very glad to have found it. It simply takes ...
10
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2answers
4k views

Finding centre point of a raster in ArcGIS?

If I have, say, a rectangular and georeferenced raster file loaded in an ArcMap 10 document (.tiff w/ associated tfw), how do I easily find its centre point and store that point in a points vector ...
13
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3answers
4k views

PostGIS raster value of a lat/lon point

I have a tiff raster in my PostGIS 2.0 database. I want to get the value of the raster at a specified lat/lon point. I have: postgresql-9.1 postgis-2.0-svn with raster support a raster imported ...
3
votes
1answer
2k views

What are nodes in ArcGIS and how do you create them?

I want to create a elevation profile of a cross section so a polyline on ArcGIS. I wanted to regularly space around 1000 points per 1700m long xsection and extract elevation data for each node/point ...
7
votes
1answer
7k views

Converting points to raster in ArcGIS?

How do I create such map from point data? I am using ArcGIS 9.3 and 10
6
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2answers
943 views

How to Match Point Data in QGIS?

How do I match the same points (WGS84) in two different point layers? I want to get the points that lie exactly upon each other in the two datasets.
4
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3answers
2k views

Problem creating a point IFeatureClass

I'm trying to create a point IFeatureClass, but my code doesn't work. Public Function CreatePointFeatureClass(ByVal featureClassName As String, _ ByVal ...
9
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2answers
6k views

Find points that lie within a set of coordinates

I have a PostGIS db, and I want to find the points that lie within some region (a bounding box). I have two sets of coordinates, from which I can get all four rectangle points that form the box (if ...
2
votes
1answer
137 views

Access points with PostGIS

I have a PostGIS table with linestring geometries and point (A) on it and I need to detrimine points (M) which located M meters from A. Distance is measured along linestrings. Any thoughts?
2
votes
2answers
429 views

Stacked point representation in KMLs

I cross posted this in the Google Earth forum but they changed the format there and I'm not sure I like the format. In my dataset I sometimes have multiple locations at a single point. GE will ...
30
votes
5answers
19k views

Joining 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 ...