(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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3
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2answers
4k views

Extracting elevation from a TIN file with a point shapefile overlay

I have a TIN file that was built off of contour polyline shapefile (I think). I have a point shapfile with a few points. How can I extract elevation of the TIN file where the points occur? I am ...
1
vote
0answers
53 views

Why is the geometry changing slightly when I import shapes into a postgresql database with postgis?

I recently posted this question when first trying to import data from a file geodatabase into a postgis database: how can I maintain curves when converting from geodatabase to postgresql using og2gui ...
8
votes
1answer
470 views

How exactly is the centroid of polygons calculated?

I would like to know how exactly QGIS Geometry tools -> polygon centroid is calculating the point coordinates. For example does it divide the boarder of the polygon into small points, take two pairs ...
1
vote
0answers
34 views

Is there a way to select polygons by geometry (right angle)? [closed]

Is there a way to select polygons by geometry? I need to find a way to detect all the polygons that have a right angle, but I can't find a tool that can do that. I'm using QGIS 2.10.1 and ArcGIS ...
3
votes
1answer
322 views

Update a table with values from coordinates on GEOMETRY in Oracle

I have 2 columns in a table that represent the X and Y coordinates. The values in those columns don't match the actual coordinates and I want to update them with the coordinates values that are ...
0
votes
1answer
45 views

How to get Lat/Lng from a Geometric property?

Alright, I am very new to GIS, my question might not even make sense, but help me get through this. I have this JSON data of some fields which have this geometry property: "geometry": ...
1
vote
2answers
103 views

Can QGIS import Multipatch geometry type?

can QGIS import multipatch 3d geometry type? What is the data structure of multipatch how computer record and draws it ? Is it solid or not??
1
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0answers
16 views

Quantum gis 2.2 - pasting templates

Is there a way to paste geometries in a workspace at the location i want? e.g. i want to paste a circle from another workspace in the workspace i'm working with. I need only the geometry, not the ...
0
votes
1answer
108 views

PyQGIS: how to transform single QgsGeometry object from one CRS to the other?

I have a polyline layer with roads in WGS84 that covers several UTM zones. For every road I need to place a set of points at different distances (in metres). To do so I want to reproject each road to ...
0
votes
2answers
185 views

What is nontopological geometry?

I need a simple understanding of nontopological geometry. I am completely new in this area so please correct me if I am wrong. As far as I understand in topological geometry the object(say a line) ...
1
vote
1answer
65 views

What does double digitized polygon mean?

I know what is a polygon but when a polygon is said to be double digitized? I failed to find a suitable meaning of double digitized after googling. I understand double digitized means digitized ...
0
votes
1answer
140 views

How to Query Oracle Geometry Data Type

How to I Query or find the type of geometry data type a given Oracle Database is using in SQL Developer (i.e. SDO_Geometry, ST_Geometry, etc)? I thought I could just descibe a feature class within the ...
6
votes
2answers
293 views

Draw SQL server geometry records as graphics on map using ArcGIS API for WPF 2.4 -can it be done and how?

I have records (of public festivals changing daily) in the in SQL server 2012 that have a geometry column (polygons where they occur). I need to show the records as graphics on a map using ArcGIS ...
2
votes
0answers
38 views

Geometry issues when digitising in QGIS

I'm digitising a large number of maps from hand drawn mud maps and digital images, and although I have used the snapping tools ("snap to vertex and segment", Tolerance 10 pixels, avoid intersections) ...
1
vote
1answer
50 views

Shared edge between two geojson polygons

I am interested in getting the coordinates of a shared edge (if exists) between two geojson polygons. I am (currently) using turfjs and geojson-equality libraries I tried this but I consider it quite ...
0
votes
0answers
101 views

ArcGIS/ ArcPy - XY coordinates of feature class does not match calculated geometry XY

Tested on: different workstations, different Windows versions; ArcGIS Desktop 10.3, different license levels Background: I use the Google Maps DistanceMatrix to calculate drive times between two ...
2
votes
2answers
77 views

Query Features in Certain Direction

I have a polyline that I would like to query features that are on it's left, right, top, bottom. I am not looking for the features surrounding it but for features that are on a certain location from ...
0
votes
2answers
68 views

Using ST_LINE_INTERPOLATE_POINT in OGR and python

I'm interested in finding the midpoint on a linestring using OGR and python. This can be a line with more segments. Could I use the ST_LINE_INTERPOLATE_POINT in python using the ExecuteSQL() method? ...
0
votes
1answer
82 views

Qgis 2.10 unable to add a new feature in spatialite via sql function “GeomFromText”

Using Python code in my plugin the function in sql language "GeomFromText(POINT(X Y))" gives the following error: "OperationalError: no such function: GeomFromText" Plugin functions in previous ...
6
votes
3answers
632 views

How to convert from SQL Server geometry BLOB to something else?

I have a CSV data file from a 3rd party that is an exported SQL Server table. They simply did a select * from foo and output the result to a text file and sent it over. In their table is column of ...
5
votes
2answers
122 views

Polygon points to Polyline

I am trying to create a polyline from the points that I query from a polygon. I have a polygon, and I am getting its edges, casting them to segments, and then use QueryNormal to get the mid point ...
0
votes
0answers
25 views

Determining North-South Line Via Watch Method?

I read about Determining North-South Line Via Watch Method recently (page 9). What is the underlying geometric/celestial reason this works? What is the error to true north given this method? Is ...
2
votes
1answer
149 views

Remove inner rings from QgsGeometry polygon in QGIS Python

I am a QGIS python user. I want to iterate over the rings of a polygon to remove holes in the polygon, so: I need to iterate over the rings in a QgsGeometry polygon I need to detect the main ring ...
1
vote
2answers
147 views

Free 3rd party library for showing geospatial vector information

Up to now, I have used GDAL to extract raster data from geotiffs and then, OpenGL to show that raster data. But when it comes to extract vector data with the help of OGR, what library would you ...
1
vote
1answer
399 views

How to resolve the postgis “type geometry does not exist” issue on installing tiger_geocode extension?

I have installed postgis extension in my db. I have few columns associated with its type in few tables and now I would like to use reverse geocode functionality in my app. Hence I tried to create ...
2
votes
0answers
34 views

how to register view geometry made by MakeLine function?

I am trying to to create a spatial view on my spatialite database. CREATE VIEW v2_pump_view AS SELECT pump.ROWID AS ROWID, pump.id AS pump_id, MakeLine( ...
4
votes
2answers
158 views

Dismantling and reassembling polyline by joining each point to its nearest neighboring point using ArcGIS Desktop?

How can I reconfigure a PolylineMZ feature class in a way as shown in the image below? I have a feature class (PolylineMZ) which contains x-sections. Some x-sections (polylines) are badly constructed ...
1
vote
2answers
33 views

Geographical Field Points of a Boundary

I gathered field points with a TOPCON hand held receiver. I saved the points as a shape file and brought them into arc map. I used the editor tool to connect the points and created a polygon. Is ...
3
votes
2answers
79 views

Construct curve of equal distance from two straight lines

Given two straight lines defined by two points each, I want to get the line which separates points nearer to line a from points nearer to line b. The attached PostGIS code is an example case, it finds ...
0
votes
0answers
31 views

PosGIS: Longest line connecting point to line

I have a point and around it lines and polygons in the rule of obstacles. I want to connect the point to each of the lines, with a line, such that this connecting line is not intersect any obstacle ...
1
vote
1answer
1k views

Google's S2 library - any alternatives?

Is there any alternative to Google's S2 geometry library? It looks it was updated 4 years back and hardly any documentation. I need a library to divide cities into zones of the area I need. S2 looks ...
1
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0answers
40 views

sql server geometry find points intersection buffer

How do I find the point of intersection of buffer?
2
votes
1answer
76 views

Testing if Geometry is convex using JTS?

I'm using the Java Topology Suite and I'd like to efficiently check if a Geometry (a Polygon in fact) is convex or not. I currently do if (geometry.convexHull().equals(geometry)) but obivously that ...
1
vote
1answer
46 views

GeoTools Geometries lost when storing features to shapefile [duplicate]

As you know, the geometry column name of schema for saving into a shapefile must be "the_geom". I have a SimpleFeatureCollection with a schema, geometry name of which is not "the_geom"; It is ...
5
votes
1answer
208 views

How can I increase performance on inserting features with polygon geometry?

I have a problem when inserting features with polygon feature class in FGDB. This is my code: ... initialising some fields (does not affect performance) m_featureBuffer.Shape = ...
7
votes
6answers
6k views

How to fix quickly a lot of geometry validity errors in QGIS?

I am working on ownership data at a US county level. I have one shapefile per county that contains thousands of tax parcels. I need to dissolve the polygons representing parcels owned by the same ...
0
votes
1answer
683 views

Using WKT.writeGeometry for 'Circle' Geometry in OpenLayers?

In my application which I'm building using OpenLayers3, I'm trying to extract the geometry of a feature to WKT using var format = new ol.format.WKT(); console.log(format.writeGeometry(geometry)); by ...
0
votes
0answers
12 views

Representation of streets/highways Geometry

I have Navtech data which provides center-lines with geometric data of the roads. The most important data for me is that it gives me the width of the road as well as the number of lanes for most of ...
0
votes
0answers
112 views

Drawing Zoning Setback Lines

What would be the process for drawing zoning setback lines for a property parcel polygon? I'm looking for a software agnostic solution - just a walk through of the general steps with enough detail ...
1
vote
1answer
39 views

Looking for geometries defining the boundaries of Canadian Location Code regions used for Meteorological Services in Canada

To be clear I have looked into the GADM datasets. The problem is that Canada has a very non-standardized level-2 Administrative Zone identification across the various Territories and Provinces. As a ...
0
votes
0answers
58 views

Remote SQL Server, Crystal Reports and Geospatial Join

I have: A remote SQL server (2008 R2) that I have access to (But NOT full control of) which contains my source data including OSGB 1936 Geometry [ESPG: 27700] In house SQL Server 2008 R2 A Crystal ...
0
votes
1answer
37 views

Double geometry coloumns in an xy event layer (ArcGIS 10.0)

I want to convert an annotation feature class to a shapefile. The annotation feature class is stored in a file geodatabase. I add two columns (x, y) for the centroid coordinates (calculate geometry) ...
1
vote
1answer
48 views

sorting polygons extracted using Fishnet

I generated polygons using fishnet in ArcMap, since the polygons didn't fall exactly on top of my raster image, I had to edit and move some of them. Now the FID of my polygons are all messed up, and ...
9
votes
2answers
85 views

Fuzzy least-coarse common partition algorithm

Given two different partitions of a shape (for argument's sake, two different administrative divisions of a country), how can I find a new partition into which both of those partitions fit, allowing ...
0
votes
1answer
82 views

Points contained in envelopes that cross date-line - java

I'm using the ESRI Geometry Java API https://github.com/Esri/geometry-api-java I want to construct an envelope and see if it contains certain points. It's possible the envelope crosses the ...
0
votes
0answers
73 views

How to create a polyline using multiple points using a PostgreSQL query?

I'm trying to use point data to create a polyline to show my bus route. Initially began with coordinates and used this to create geom using the ST_MakePoint function (written to the BusRouteData ...
2
votes
2answers
119 views

Merging lines (that might cross) at common endpoints without multi-part features in the result

I have a polyline dataset I'm trying to merge / dissolve segments based on an attribute into continuous single lines. The problem is that some of those segments cross each other but need to be ...
1
vote
0answers
17 views

QGIS 2.0.1 Translate Feature

I have a layer containing linestrings and want to move those that are too close to each other. I seem to be missing something in the moving part though: layer = iface.activeLayer() def moveFeature ...
2
votes
0answers
80 views

how to orthogonalize building outlines

I'm looking for a way to orthogonalize building outlines which I've extracted from a high-res DEM. I'm using the FOSS GIS stack (QGIS, GRASS, SAGA, PostgrSQL, PostGIS) and can code in Python (or ...
0
votes
0answers
42 views

Javascript - Convert arc polyline to arrow polygon

I am using the arc.js library to generate arcs on my map. Those arcs are polylines. I would like to transform those arcs into arrows polygon. To create the arc, I need the start and the end ...