(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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7
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3answers
11k views

Create a geography/geometry column from x and y fields - SQL Server 2008

Hy guys, I'm new in SQL Server 2008 and I hope you will understand my question/need. Thus, I have a table which contains 3 fields (Name, Lat and Long) in my data base (spatial). I want to create a ...
2
votes
1answer
2k views

How to get the radius of a “circle” in Openlayers

How do you get the radius of a circle in openlayers? I have searched quite a bit and cannot find any resource for this. please help. Here is my code but I want the radius or circumference of the ...
7
votes
2answers
2k views

What is the best way to extract the geometry of a road from OSM data?

What is the best way to extract the geometry of a road from OSM data? The goal is to display segments of highway that are closed due to weather. The weather data consists of positions (in KM measured ...
2
votes
1answer
659 views

Using MS SQL 2005 as the data store in GeoServer

In my project, I am trying to set up a simple WFS service in GeoServer in order to create a layer consisting of point features. I have succeeded doing so with the points being stored in a shapefile. ...
1
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1answer
2k views

ArcGIS API for Silverlight - pass geometries to ESRI service

How would I test this service to find what it wants? ...
4
votes
1answer
3k views

Transforming geometry coordinates from SRID 4326 to SRID 3011

In SQLServer geometry field, I want to change the coordinates of geometry from one spatial reference system to another spatial reference system (from SRID 4326 to SRID 3011) by using ST_Transform. But ...
3
votes
2answers
8k views

How I get SRID from Geometry field

what is the function for getting SRID from Geometry field. I have inserted a shapefile into SQLServer table with Geometry field defined. I know the projection of shapefile is Swreff99_1800 ...
1
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2answers
1k views

what is the format of Geometry data type of SQLServer 2008

I want to know, In which format the Geographic data stored in geometry data type of SQLServer 2008.it looks like a long string,like 0xE6100010466DFEOA4089663524....... for one polygon. My second ...
0
votes
1answer
2k views

C# library for converting geom field of SQLServer into set of google latlng

Is there any C# library which can convert the geometry field into set of google latlngs? I have stored a shapefile into SQLserver table. From Sqlserver i want to read the geometry field data and want ...
2
votes
1answer
455 views

The minimum bounding circle of geometry that crosses the 180th meridian

Background: I've been given a task where I have to calculate the minimum bounding circle of Alaska (for the purpose of running a Roeck test). I'm using the Census' state level geometries available ...
10
votes
3answers
14k views

How to convert .shp to .csv including attributes AND geometry?

I have a .shp file with 60k+ entries, all of which are polygons with corresponding attributes (acreage totals, landowner names, tax ID #s, etc.). What I ultimately need is a .csv file with all of ...
6
votes
1answer
3k views

Geometry from multiple selected features into one geometry

Lets see if I can explain what I'm trying to do. First of all I have developed an AddIn for ArcMap that can take one selected feature (Polygon) on a layer, grab the geometry of that feature, and save ...
6
votes
2answers
763 views

Get shortest distance between two geometries in ArcPy

I'm using ArcPy and using a cursor to step through one polygon feature class. For each of these 'source' polygons, I am creating a SearchCursor to find all polygons in a second feature class that ...
3
votes
1answer
817 views

geometryType property of Vector Layers in OpenLayers

ORIGINAL: I have a couple questions that are focused around the geometryType property with vector layers. When you create a vector layer you can set the geometryType property to limit the geometry ...
1
vote
1answer
908 views

What is geometry datatype?

What are the basic that one should know about geometry datatype? How is it computed ? Why do we need geometry data type? Edit: I wanted to know why there is a different datatype called geometry. Is ...
9
votes
5answers
1k views

Measuring straightness of a curve segment (represented as a polyline)

I'm working on an automatic elevation contour labeling algorithm and one of the factors that I want to take into account when deciding the positions of labels is how "straight" a particular segment of ...
4
votes
0answers
239 views

Topology - To be, or not to be, that is the question [closed]

Topology, I mean "real" topology, is not a new concept and it's available since a long time in GRASS gis. I won't speculate the reasons myself but, after a long period of spaghetti model ...
1
vote
0answers
245 views

Problems with Multipatches

I have some polygonal features that have minimum and maximum z values. I'm trying to calculate the difference between a fixed extruded polygons and the sum of extruded related polygons. Here's how ...
5
votes
3answers
1k views

Any .NET library to calculate polygon area?

Is there a .NET library to calculate area enclosed by polygon made up of geo coordinates (lat longs)?
3
votes
2answers
681 views

How do I find the points of intersection between a small circle and a great circle?

I only actually need to intersect a great circle arc i.e. the shortest path between two points, with a given small circle. I found this tutorial for intersecting two great circle arcs, but ...
5
votes
1answer
242 views

Intermediate points on a small circle

I need to interpolate lat/lon points along a small circle, with a given centre and radius. I've successfully used these formulas for great circles. What is the equivalent for small circles?
3
votes
2answers
427 views

Determine point relation to given line

In ArcGIS engine I have a polyline with From and To points. I also have a Point. How can I determine if the point is located on the right or left of the line on the plane considering the direction of ...
1
vote
0answers
665 views

ArcGIS 10.0/arcpy: Can't retrieve the points in a polyline geometry obect: any idea why?

My arcpy script builds a Python dictionary, dictCLPnts, that holds the geometry objects of a polyline feature class. The following code snippet shows the attempt to access the geometry object with ...
4
votes
0answers
705 views

OpenLayers: WFS request to GeoServer to retrieve “name” & “featureNS”

Using WFSGetCapabilities I sent a GetCapabilities request to GeoServer. From the result of WFSGetCapabilities().read(), I can loop each featureType and retrieve some basic info(e.g., name, title, ...
3
votes
2answers
1k views

OpenLayers + Geoserver: how to dynamically retrieve the “geometryName” of a feature layer in GeoServer

I am trying to get the list of feature layers on GeoServer and then user can add layers into map at anytime they want. my question is: when using OpenLayers.Protocol.WFS loading a layer, is ...
4
votes
4answers
1k views

Is there a way to convert 3D polylines to 3D points in ArcGIS?

I need to convert a huge number of very dense (densified to 1m) 3D polylines to 3D points. I need each vertex along the line and no duplicates (two of the same XYZ coordinates) if possible. Is there ...
5
votes
5answers
1k views

Python, shapely library: is it possible to do an affine operation on shape polygon?

I am trying to create a rotated rectangle in lat/lon coordinates. Basically I have the coordinates of the center and rotation angle around the center. Is it possible to do using, shapely or gdal, or ...
26
votes
3answers
6k views

Visualising WKT geometry string in QGIS

A very simple question: Is there a simple tool in QGIS to graphically visualise geometry formatted as text? Example geometry: "POLYGON((571178 6337246,571178 6402217,598061 6402217,598061 ...
0
votes
1answer
2k views

Moving graphics in Esri Flex Feature Layer

I have an ESRI Flex 2.3 FeatureLayer with some graphics in it. I am able to access the graphics geometry and parse the geometry as Esris MapPoint class for Flex Api. I am calling the update(x,y,srs) ...
3
votes
1answer
364 views

Open dataset(s) with centroids or other geometry for WOEIDs?

The Yahoo! GeoPlanet data is available for download but this data only includes the object hierarchies without any associated geometry. Do anyone know if there is an open source for geometry ...
2
votes
3answers
1k views

How to create Esri Flex Geometry from WKT

I am working with Esri flex 2.3 API, I am also using Abode BlazeDS for server side binding. I am sending a geometry as WKT from server into my flex client and I am looking for a way to convert the ...
2
votes
1answer
234 views

LinearRing getVertices implementation

I'm fairly new to OpenLayers so please excuse me if this is an ignorant question. I'm curious why the LinearRing getVertices implementation getVertices: function(nodes) { return (nodes === true) ...
2
votes
1answer
432 views

polygon map overlay algorithm

There are many algorithms for binary map overlay operation in vector data format which take two layers of map and produce resultant layer i.e overlaid layer as output. I am wondering whether there are ...
1
vote
1answer
289 views

Building orientation and simplification using Opencarto Java library

I need to find out orientation of buildings and perform simplification of sides of buildings with a tolerance. I came to know from StackExchange that OpenCarto has useful libraries for geometrical ...
3
votes
3answers
196 views

Is the Intersection Operation Commutative?

In map overlay, is intersection of map layers a commutative operation ie layer_A intersection layer_B = layer_B intersection layer_A? If layer A is a square and layer B is a triangle. In this case, (A ...
2
votes
1answer
111 views

Outward buffering

I get the ConvexHull of a set of polygons using ST_UNION and ST_CONVEXHULL functions using PostGIS. I want to know how to create an outward buffer of the created convexhull in PostGIS?
4
votes
5answers
6k views

Calculate midpoint from a series of latitude and longitude coordinates

I've got a series of longitude and latitude coordinates which represent a building outline e.g. -0.5485381346101759,53.2285150736142 -0.5482220594232723,53.22842450827133 ...
5
votes
2answers
5k views

Find closest lat long to an input lat long (SQL Server 2008)

I have a point cloud in my database (SQL Server 2008 spatial). That is about 6 million records. There are 3 columns: id, value, geom. What is the optimal way of getting the 'value' at input lat long?? ...
9
votes
3answers
369 views

Invalid geometry zoo

Many a time and oft I've spent hours struggling with bizarre bugs resulting from invalid geometries. The symptoms vary greatly, including: Database slowdowns Incorrect\Null query results Log files ...
4
votes
1answer
329 views

Sort by geometry using INHERITS?

hope everyone's doing well. I have a statewide point data set (parent table: 600K rows, 500 columns) I need to analyze at multiple scales based on several different spatial divisions. I'll also need ...
6
votes
3answers
508 views

How could I compare polygons with appropriate circle?

My problem is that I have a polygon shape file with 1034 records which are the Greek municipalities. My goal is to compare the shape of every record with the circle. In other words, I want to observe ...
5
votes
1answer
1k views

How do I find the intersections of 2 circles on earths surface?

I have the circles' center in lat & long, as well as the radius in meters. How do I find the circles intersections? Edit: EXAMPLE: Circle 1: Center on Earth's surface (43.564627,-116.220524) ...
13
votes
5answers
520 views

Terminology: Polygon or Area?

When writing about GIS geometry I'm unsure whether to use the term "polygon" or "area". In particular, does the word "polygon" suggest a specific type of geometry? For example, a colleague suggested ...
9
votes
4answers
270 views

Is there a standardized or “most used” dummy Z value?

Creating and importing both 2D and 3D data, I have many times encountered the situation where I have no Z value for a coordinate set, that the value of a Z coordinate seems out of range (like -99, ...
19
votes
3answers
5k views

How to store lines and polygons in JSON documents?

Looking at the increasing NoSQL movement and considering that databases like MongoDB offers a new perspective in flexible data storage for GIS. What is the best way to store lines and polygons in ...
5
votes
1answer
294 views

Which projection casts rays from a point on the surface of the globe to a cylinder?

What is the name of a map projection that casts rays from a point on the surface of the globe to a cylinder? Some people who make sundials put a map of Earth on the sundial. I want to use the "right" ...
5
votes
2answers
287 views

Does the Chamberlin trimetric projection map (some) great circles to straight lines?

I know that, in general, the Chamberlin trimetric projection maps most great circles on the sphere to some sort of non-straight curve on the flat map. But what about the 3 special great circles ...
10
votes
2answers
5k views

Using python in ArcGIS, create a line of varying distance from an origin point

What I'm trying to do is create a line feature from a single point, using a set distance and angle. Using ArcGIS and Python (I hope). Here's the scenario: Say I have a point at these coordinates: ...
32
votes
4answers
6k views

What are the pros and cons of PostGIS geography and geometry types?

My company uses geometry (the_geom) data type for storing geospatial data. I've recently been acquainted to the concept of geography (the_geog) data type which, as I understand it, stores the SRID ...
3
votes
4answers
705 views

Update geometry(polygon) of shape file based on a point layer

I have two shape files. Polygon shape file Point file contains some points. Now i want to delete all the vertex of polygon shape file which are available in point file. I am using ...