(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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2
votes
1answer
287 views

Multipoint vs point PostGIS

Is it normal to use the geometry type 'multipoint' instead of 'point' knowing that I use it to store only one point. How can I convert from multipoint to point
5
votes
3answers
97 views

What is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator?

Stemming from my other question: When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?, what is the PostGIS 2.x equivalent of the pre-PostGIS 1.5 ~= operator? It ...
2
votes
1answer
80 views

When would a PostGIS geometry compare using ~= return true when ST_Equals returns false?

I have a couple of featureclasses in a 10.2 geodatabase/PostgreSQL 9.2.2 database and I've been struggling with the FeatureCompare tool--it is telling me geometries are different on some features ...
1
vote
2answers
85 views

Problem - ST_AsGeoJSON return text with accolade

I am saving a result of ST_AsGeoJSON(..) into csv file. But the results I got can't be interrupted as an object later on. How can I polish and delete the accolades that I don't need. ...
0
votes
0answers
21 views

Is there a way of converting polygon vertices to points using GDAL python? [duplicate]

I have an ArcGIS standard license and I want to convert polygon vertexes to points in a script. Since I don't have a good enough ArcGIS license I've been using ET Geowizards to get the points. The ...
1
vote
2answers
197 views

Get the vertices on a LineString either side of a Point

I have a shapely LineString and defined a shapely Point which lies along the LineString. How can I find the vertices of the LineString which lie either side of the point? (split the line in two). ...
0
votes
0answers
83 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
votes
2answers
112 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
votes
1answer
558 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
vote
0answers
87 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 ...
1
vote
0answers
107 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 ...
0
votes
0answers
187 views

Feature.geometry.transform not working

// World Geodetic System 1984 projection var WGS84 = new OpenLayers.Projection("EPSG:4326"); // WGS84 Google Mercator projection var WGS84_google_mercator = new ...
8
votes
1answer
258 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 ...
0
votes
0answers
277 views

Polygon to point conversion in ArcMap

I tried to convert polygons to point using Feature to Point under data management toolbox in arcGIS 10.2 (got it from uni. licensed). I got the point layer but it is not showing anything. I added X ...
2
votes
1answer
214 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
votes
2answers
153 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
vote
1answer
63 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 ...
1
vote
0answers
138 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 ...
0
votes
0answers
30 views

Identify primary routes in Postgis

I have a table of linestrings that make up a route network. I want to identify the primary routes and separate out the interconnections. Problem is that the primary routes are split into separate ...
1
vote
1answer
163 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
votes
2answers
228 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 ...
0
votes
1answer
89 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
vote
1answer
91 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 ...
0
votes
1answer
73 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 ...
1
vote
3answers
293 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 ...
0
votes
2answers
146 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
322 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
vote
1answer
69 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 ...
0
votes
1answer
97 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
votes
3answers
235 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 ...
0
votes
0answers
191 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) ...
3
votes
5answers
708 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
votes
1answer
460 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
835 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 ...
4
votes
2answers
694 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
votes
3answers
1k 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
216 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
40 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 ...
1
vote
2answers
140 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
votes
1answer
274 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
vote
0answers
28 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 ...
1
vote
0answers
129 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 ...
1
vote
1answer
61 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
votes
2answers
155 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 ...
2
votes
1answer
132 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.
0
votes
1answer
94 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
votes
0answers
78 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
1
vote
1answer
671 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 ...
0
votes
0answers
277 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 ...
1
vote
2answers
325 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, ...