(1) abstract geometry; (2) storing geographic data in projected coordinates; (3) a generic ESRI term for vector features; a class for "geometry" objects.

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125 views

Which geo-location available in Twitter data should I use?

I am extracting twitter location on my side.Few tweets has perfect location but in most cases additional details are available (i.e. Country,bounding_box,poly lines etc) So confused regarding ...
5
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2answers
127 views

Can someone give the absolute lowdown on the following list of spatial operators

Ok, I have to admit, I don't really delve too deep into the semantics of the spatial operators list below, I'm more of a user, I write software to drive the SQL most of the time and don't really think ...
3
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1answer
791 views

Multiple geometry columns for points, lines, and polygons in spatialite?

I'm rather new to the GIS world and even newer to Spatialite and trying to create a new DB for our application. I would like to create spatial index(es) on the geometry column(s), but our geometry ...
1
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0answers
109 views

Error When Generating INSERT Statements for Geometry Field SQL Server

I am populating a column of linestrings from a list of points in sql with which I use to create insert statements to populate an ID and a geometry field in a table. This creates a temporary dataset ...
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0answers
128 views

Inaccurate result while clipping on gis data

I am trying clip polyline data using a polygon geometry. I am using itopologicaloperator to do this task. However, resultant clipped data is off by 1 feet. Meaning that the polylines at the boundaries ...
9
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2answers
409 views

What is the precision of SELECT DISTINCT on PostGIS geometry column?

I wonder what the precision of the SELECT DISTINCT operator is on a PostGIS geometry. On my system, the following query gives me a count of 5, which means that the inserted points are considered equal ...
3
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1answer
344 views

Retrieve geographic coordinates from OSM imported data

We have just finished importing OSM data into our PostGIS (Postgresql) database. And we are having difficulty understanding the geometry of various shapes imported. We run a query to retrieve the ...
2
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2answers
184 views

How to convert Point coordinates into CSV format?

The GDAL documentation describes how to convert a ShapeFile into CSV data. The layer create options (-lco parameter) allows to prepend the coordinates of Point features to the actual attributes ...
1
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1answer
72 views

Mismatch in area calculation using Field Calculator vs Group Stats in QGIS 2.0

I have two polygon files (A being my area of interest and B being a categorised land cover layer). Both layers were in the same projection (projected and not geographic). Using QGIS 2.0, I used the ...
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0answers
157 views

pgRouting results to LINESTRING geometry type

I am doing some routing queries, using pgRouting's second version of pgr_trsp function. What I can't do effectively yet is storing the results. That is, I want to able to store in a table: either ...
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1answer
257 views

Get Polygon or IGeometry from Envelope in ArcObjects

I would like to create a Polygon Feature from the geometry of an IEnvelope in C# ArcObjects SDK 10. Is there an easy way how to do it?
3
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2answers
288 views

How to rename points by clockwise direction or change starting point in polygon features?

I have a polygon feature class. I convert it to a point. Name of field (for example !Number!) in a point feature converted from polygon "A2"(The first point should be in the upper left corner ...
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1answer
106 views

How to automate creating box (rectangular) polygons in ArcGIS for Desktop?

Can anyone suggest a way to automate creating rectangle shaped polygons in ArcMap? If I had many 30m x 60m rectangles to digitize and I just want to click a starting corner coordinate on screen, ...
1
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1answer
109 views

Clip geometries in table based upon value

I have defined a view in postgres that returns a set of polygons and can be queried as follows:- SELECT wkb_geometry, grade_count FROM ng_schema.grade_count_report [sql.where] order by grade_count ...
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1answer
87 views

Missing a Geom field in PostGis

I am working in a Database preaparation for that I exported a shapefile from Qgis to PostGis.The Problem is this: In Qgis I can see a Polygon feature but when the same polygon feature is exported to ...
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3answers
360 views

KML to Shapefile using GDAL (LIBKML) - MultiGeometry data not transforming

I am trying to convert a KML file to Shapefile using GDAL (ogr2ogr). Regular KML files convert fine but KML files containing MultiGeometry features (eg: Geometry containing both Point and Polygon) do ...
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2answers
193 views

Calculating minimum/maximum width for overlay of two polygon strips in ArcGIS or some Opensource GIS

Is there some solution for calculating minimum and maximum width for overlay of two polygon strips? When I clip these strips the result is another strip with variable width about 1 km and 20 km long. ...
5
votes
1answer
440 views

How is ST_PointOnSurface calculated?

The PostGIS documentation states that ST_PointOnSurface returns "a POINT guaranteed to lie on the surface". It seems like this function could be trivially implemented to give results that satisfy the ...
1
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1answer
79 views

PostGIS Geometry folder is missing

I have installed PostgreSQL 9.2 and PostGIS 2.0.3 from Stackbuilder. My template_postgis_20 does not have a geometry table only spatial_ref_sys table. Is that a problem? and if not how can i create ...
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1answer
121 views

Problem of linear records with zero shape length and no geometry in attribute table

I am working with a bicycle and pedestrian facility file geodatabase in ArcMap. I noticed a some of the records in the shapefiles/feature classes have a shape length of zero in the shape length ...
2
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3answers
295 views

Fastest way to join points table to polygons tables in ORACLE

I have two tables in 11g oracle db, one with points geometry, one with polygons. Currently I need to enrich the points table daily with the name of the polygon (country) that the point is inside, but ...
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0answers
223 views

How to get the top left and lower right coordinates of polygon in ArcObjects?

First of all, draw the rectangle ESRI.ArcGIS.Display.IScreenDisplay screenDisplay = Map1.ActiveView.ScreenDisplay; screenDisplay.StartDrawing(screenDisplay.hDC, (System.Int16) ...
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5answers
956 views

How to Identify and Delete duplicate vertices?

I am trying to figure out how to delete duplicate vertices. I have successfully determined that there are duplicate vertices using PLTS Data Reviewer, but I am confounded as to how I identify and ...
4
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1answer
640 views

Buffer polygon inward by percentage of area [duplicate]

I would like to buffer a polygon inward by a percentage of its area, using the polygons below as an example. How could I shrink each polygon inward resulting in a 35% reduction of area? I am using ...
5
votes
3answers
1k views

How to convert geoJSON to python objects?

New to the site, and to geoJSON, and to python. My goal is to read in a file with geoJSON data, and use it to generate shapes to be used in an application that is using python scripting. Python has ...
5
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2answers
912 views

How to efficiently determine if a collection of coordinates (polygon) is an ellipse?

I'm attempting to determine a geometry type based on a collection of coordinates and have come across a situation where I'd like to differentiate between what is a "polygon" and what is an "ellipse". ...
6
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3answers
2k views

How to fill a hole in a multi-polygon layer on QGIS 2?

I need to fill a hole in a multi-polygon layer on QGIS 2.0. I've set the snapping option for the layer as follows : mode: to vertex and segment tolerance 4 pixels avoid intersection "enabled" ...
7
votes
1answer
264 views

Draw middle ordinate perpendicular to chord, out to curve, with arcpy

I've been assigned to find the radius of road curves. My boss found this article describing a pretty straightforward method of doing so: find the start/end points of the curve; create a chord; ...
2
votes
1answer
41 views

How to generate features to test different implementations of LinearRing?

I have some code that throws the following exception: Points of LinearRing do not form a closed linestring and I want to check if my code is calling this correctly by supplying some features that ...
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2answers
153 views

Distance between latlongs varies in different projection systems?

I have shapefiles with correct projections. The SRS is EPSG 32735 (WGS 1984 UTM 35S) Now, I have these two coordinates from this projection system: (31.3751,-23.4388) and (31.3779,-23.4355). ...
2
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1answer
345 views

Map projection lat, lon to pixel?

I'm trying to find the concave hull of a lat, lon pointset but when I project my points on my map it doesn't look like expected. I've tried a lineare projection and a spherical projection. My data is ...
1
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0answers
30 views

PostGIS. Obtain the rotation between two equal Geometries

I've got two features with the same drawing (poliline) but one is rotated relative to the other. I would like no know in PostGIS the rotation between the two geometries to apply this rotation to a ...
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0answers
150 views

Problem import shapefile in PostGIS database

I am having a Polygon shape-file. When I try to import this shape-file in PostGIS some of the attributes in Geom Field is found empty. But in attribute table when I select that polygon It is visible ...
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1answer
71 views

ArcObjects- IBorder.GetGeometry() in Python

I am trying to get geometry of frame border trough IFrameElement.Border. I do receive IBorder object, which has .GetGeometry() method. How do I use this method to get geometry of the border? I can ...
2
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2answers
175 views

OSM linestring shown as point

I have loaded the following file http://openstreetmapdata.com/data/coastlines to postgreSQL. In visual studio with gdal/ogr and geos enabled: SELECT geom FROM waterpoly WHERE geom IS NOT NULL LIMIT ...
3
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1answer
162 views

How to convert a line to points?

I'm working with QGIS and I want to convert a line into many points, does someone know how? Thanks.
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1answer
107 views

ArcMap toolbox script with draw geometries parameter

I have an arcpy script in toolbox, that need one additional parameter to draw geometry(ies) which will work as a filter. I have done something similar using arcobjects using ...
0
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0answers
86 views

How to find the list of TMC codes by region or by geometry polygon?

Can you please suggest a way to find out all the TMC (Traffic Message Channel) codes by region or by Geometry polygon values. My area of interest : USA
2
votes
1answer
963 views

PostGIS Select Union of Polygons

I have a Postgres 8.4 PostGIS 2.0 enabled database and I've loaded it up with a bunch of shapefiles. I'm trying to get the database to do on-the-fly unions of geometries. Here is the query I'm ...
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0answers
315 views

Publishing PostGis table using GeoServer REST returns error when geometry column is NOT named “geom”

I tried publishing an existing PostGis table with geometry column named "wkb_geometry" to Geoserver using its REST API. I used the following command: curl -v -u admin:geoserver -X POST -H ...
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2answers
411 views

Convert 3D WKT to 2D Shapely Geometry

I have the WKT of many linestrings which contains three dimensions, however my script only requires a two dimensional linestring and I therefore want to discard the third dimension. My current code, ...
2
votes
2answers
839 views

How to convert Geometry type column to degree Minutes Second in SQL Server 2008 R2

I have shape column of type geometry and I want to convert X and Y coordinates into Degree Minutes Second format using SQL query and i am using sql server 2008 R2. Currently I got Lat and long using ...
1
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1answer
298 views

SQL Data: How to draw circles with a radius based on lat/long data in DB

I have a . sqlite file with many columns, two of those columns being lat and long. I've been searching around for a bit now (don't think I want to be using BuildCircleMbr from spatialite?) but I'm ...
4
votes
2answers
5k views

How to remove duplicate features with the same geometry in ArcMap?

Is it possible to uniquely identify each geometry in a feature layer? Essentially I have a polygon feature layer with many rows of data represented by the same geometry. I would like 1 row for each ...
2
votes
1answer
192 views

Center point approximation of a polygon

I would like to get a center point approximation of a set of polygons so I can do a NN lookup to use for assignment instead of a point in polygon query. Lets say I have this set of polygons: I ...
1
vote
1answer
421 views

SQL 2012 - How can I convert MultiLineString to Geography?

I have a Geometry LineString that I wish to convert to Geography. Since the Geometry isn't valid , When I use MakeValid on it, SQL convert it to MultiLineString and than the Geography creation is ...
0
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1answer
233 views

SetGeometry problems when using python/ogr

So i am trying to use the difference function and i pretty much create the new file i want but the Geometry is empty. No error is produced. any help would great! Thanks. #!/usr/bin/env python import ...
1
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1answer
552 views

What to do if PostGIS gives error that “geometry requires more points”?

I have a .TAB file. I convert it to ESRI(shp)-->sql and insert it into database. Using PostGIS when I want to convert the data into ESRI file, it shows an error: geometry requires more points ...
0
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0answers
171 views

Openlayer seems slow when zooming / panning on vector (geometry line) from geojson. Why?

I have a layer with 7 lines . when I zoom on some of the lines , the maps seems to be very slow. I thought it might be because I bring a lot of points to the client (that represents the line) aa ...
5
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1answer
322 views

Can ArcPy 10.1 be used to generate true curve elliptical polygons in a file geodatabase?

As background, this question arose from trying to answer a question on How to generate overlapping polygons from lines output from Table To Ellipse tool? Using the ArcMap GUI it is very easy to ...