(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
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1answer
119 views

Use arcpy to check whether feature class geometry has ZM

I am looking for a programmatic way using arcpy to determine whether or not a feature class (FC) has Z and/or M geometry. It's easy enough to get the geometry type using the code below, but this just ...
1
vote
1answer
38 views

Is averaging the points for lines and multilines a valid method of getting the centroid?

I'm working with a SqlGeometry SqlServer DB and am a novice to GIS. I'm tasked with getting the centroid of a series of geometries from C#'s SqlGeometry object. This is fine as it has a GetCentroid ...
1
vote
1answer
108 views

How to import geometry data from csv file to postgres?

I have geometry file in *.xls file, but when I save in *.csv it say "some feature in your workbook might be lost if you save it as CSV (Comma delimited)" however I keep that file anyway and when I ...
0
votes
1answer
183 views

Get the vertices on a LineString either side of a point (Sql Server 2008)

I have a point that sits on top of a LineString, both Sql Geometry types. POINT('0.5 0.5') LINESTRING('0 0 NULL 1, 1 1 NULL 1') I want to find the vertices of the LineString that lie either side ...
1
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0answers
23 views

Needing to find parent zip code of a bunch of missing zip codes in the US

We're using MapPoint to export zip code / territory combinations. Unfortunately, the export doesn't include PO Box zip codes which mean that we're missing a lot of zip codes The PO Box zip codes are ...
0
votes
1answer
41 views

table update w/ cursor geometry conflict

I'm creating a table using arcpy with a list of results (stored in 2d lists) following an update to some features. This can sometimes include geometry, so I've attempted to substitute those for a ...
3
votes
0answers
66 views

What is the area that OGR extracts from the (geometry) shp files for polygons?

The ESRI July 1998 technical documentation for polygon shapefiles at page 10 makes no mention of either area measures or length measures (apart from byte/record-layout matters). Yet OGR enables me to ...
3
votes
1answer
101 views

Gaps and overlaps appear after cutting a previously topologically clean shapefile?

I'm using QGIS 2.2 and I have a polygon shapefile which was created by someone else. I have managed to get the shapefile to a topologically clean state by running v.clean but when I tried to cut the ...
3
votes
3answers
147 views

Drawing some points in QGIS 2.4 using Python

I'm new to PyQGIS so here goes: Give a new QGIS project, how can we draw some Points on the map? I tried the following but nothing showed up. Should they be placed in a Vector layer before they can ...
0
votes
2answers
163 views

How to store lat/long in PostGIS database? [duplicate]

I have a bunch of points in a text file that are represented using lat long (116.3158516 39.9748016). I import them into my GIS enabled database and create trajectories using st_makeline() as ...
2
votes
0answers
105 views

QGIS : cannot change the z-coordinate of a point shapefile using the wkb geometry format

I am using QGIS Desktop 2.5.0-Master with GDAL/OGR 1.11.0 on a windows 7. I am working on a little pyQGis script that should modify the z-coordinate of points in a vector shapefile based on a value ...
0
votes
1answer
846 views

Can variable be set to reference in_memory workspace object in ArcPy?

This is an offshoot question related to a question I posted earlier. I have the following arcpy code that inputs a Python list of polygon geometry objects to the Union_analysis tool, which then ...
1
vote
0answers
56 views

QGIS 2.4.0 doesn't support multiple types of geometry in GML file

I'm testing GML 3.2.1 data according to INSPIRE Data specification (version 3.0). Data for theme Cadastral Parcels shall have both polygon geometry and definition point. When I download data from my ...
0
votes
2answers
156 views

Count the number of points in a (multi)polygon in shapely?

I'm using Python, Shapely and Fiona to process some shapefiles. Is there an easy way to count the number of points in a polygon/multipolygon in Shapely and Fiona?
0
votes
1answer
64 views

Add Marker on the polygons' centre using Openlayers?

I have written a code to draw polygon from the WKT format.Now I need to add the marker at its centre. In the following code I have passed the centre and shape in WKT format(extracted from database). ...
2
votes
1answer
145 views

How to get the width and height of a rectangular polygon in PostGIS

I have a table with point features saved in the my PostgreSQL database, and I can run the following query to get the extent of the point features and I turned the extent back into a geometry: SELECT ...
3
votes
1answer
104 views

Extract longitude latitude and radius from POSTGIS column

I have entered the circle in the Geometry type column (name=shape) in my POSTGIS as following: ST_Buffer(ST_MakePoint($longitude, $latitude)::geography, $radius)::geometry Then I extracted the ...
1
vote
1answer
146 views

PostGIS get geometries within a radius of n meters using WGS84 [duplicate]

select * from zones z where st_intersects(z.geom, st_Buffer(ST_SetSRID(ST_Point(2.336031, 48.863172), 3857),1)); It looks like the 1 in the st_buffer is being interpreted as degrees, I need to find ...
2
votes
1answer
82 views

Is a point within a polygon

I need help in this question. To explain briefly -- the question is: Whether a point with coordinates lng:-80.087535 lat: 42.054246 lies over or under line with coordinates: lng: -80.267831 ... ...
0
votes
1answer
102 views

selecting elements of a specific geometry type in PostgresSQL/PostGIS

I was reading a postgis tutorial and noticed that unlike working with shapefiles, one can actually store different types of geometry in postgres. In a table created with multiple geometry types, the ...
9
votes
2answers
988 views

why do people use geometry to represent geography?

Historically I've mainly worked with simple latitude and longitude coordinates in a SQL Server. I stored them as a geography datatype in SQL Server, and rendered them on a variety of displays ...
0
votes
0answers
22 views

Tools to generate all the possible geometries meeting specific constraints

I have an area = 2d polygon (generally a 4-side shape). I would like to generate all the possible rectangles matching the following constraints: that fall within the surface of the area with a ...
1
vote
1answer
77 views

Set default projection of geometry objects in arcpy

I have a script that creates a polyline geometry from scratch using some math to generate coordinate pairs. At the same time, there is a user-defined polygon shapefile that is used to "erase" the ...
2
votes
1answer
2k views

How to draw polygons from the python console?

I've been visiting and revisiting the page on geometry handling in the PyQGIS Cookbook: https://www.qgis.org/en/docs/pyqgis_developer_cookbook/geometry.html but can't seem to figure out how to get the ...
3
votes
1answer
395 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
1answer
771 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
2
votes
0answers
78 views

Is there a way to eliminate duplicate 'point clusters' in SQL Server 2008 r2 spatial?

I am using the ST.Distance function to identify clusters of geometry data points. Each point has a unique reference number associated with it. I would like to eliminate duplicate clusters from the ...
1
vote
0answers
24 views

Buffering/extrusion of a dem surface

I have a surface representing a DEM and i would like to add it some thickness. If i simply duplicate the surface and translate it down by my thickness, i get non uniform thickness, ie thinner where ...
1
vote
1answer
51 views

Changing order of parts in multipart geometry using ArcGIS for Desktop (or ArcPy)?

Is it possible in ArcGIS to change order of the parts in multipart geometry? In the context menu i founded "insert before" , "insert after" but it never comes active ... or is it possible via ...
0
votes
1answer
256 views

Using Z and M feature geometry to create line graph in ArcPy/Python?

I am a Python (v2.6.5) noob trying to plot a series of 3D polylines into graphs. So far I've come up with: # Import system modules import arcpy, os, sys, string from arcpy import env ...
6
votes
2answers
900 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
498 views

Calculating geometry area in ArcGIS for Desktop using ArcPy?

I have a polygon shapefile and I want to write a Python script to add a field named "area" and calculate its geometry areas. The script is like this: ...
1
vote
0answers
58 views

Why does the postGIS file lose geometry?

I am loading shapefile data from a GPS into PostGIS via Leica ZenoOffice. This apparently imports fine with it's geometry in the attribute table. However, when I add a postGIS layer in QGIS the file ...
3
votes
2answers
10k 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
vote
2answers
354 views

Export polygon in geojson as multipolygon

Anyone knows if is there any way to export a polygon layer in geojson, as multipolygon? I have a multipolygon shapefile. But there are single and multi polygons. When I export it to geojson, I got ...
1
vote
1answer
72 views

Geometry error in roadnetwork

I have a road network table. When I check st_isValid(the_geom)='f', I am getting an error: NOTICE: IllegalArgumentException: point array must contain 0 or >1 elements ERROR: Exception in ...
3
votes
1answer
6k views

Making POINT from longitude/latitude coordinates in existing table using PostGIS?

I would like to make a POINT using the longitude and latitude columns of an existing table. Here's a link to the documentation of ST_MakePoint. Here's my table: CREATE TABLE sysinst.bio ( oid ...
2
votes
1answer
434 views

Converting set of points to polygon using C#?

I want to convert a set of gps ponints to polygon.I used a simple loop to convert it to a WKT and than used makevalid() in sql server and save it in a gemetry column in databasae.Is this way right?or ...
0
votes
0answers
27 views

Drawing geometry and attaching it to featureclass with arcobjects and Add-in button

I am newbie to ArcObjects and exploring classes. I want to have form created on add-in button click.(Form contains certain text boxes for input) That shall create a new feature class and then allow ...
6
votes
2answers
788 views

IFeatureClass.Search throws error “0x80041599 The number of points is less than required for feature”

I am creating a buffered geometry around a point feature in order to search for other nearby features. I use the TopologicalOperator to create my buffered geometry. I am attempting to search a feature ...
4
votes
2answers
124 views

Map location of unknown point with distances to two known points

I'm trying to develop a function in R that will locate a point (A) on a map given distances between that point A and two other points (B and C), for which exact coordinates are known. The problem I'm ...
3
votes
1answer
246 views

OpenLayers: How to get *real* centroid of a Line Geometry/Feature?

I have declared a line geometry as: var lineString = new OpenLayers.Geometry.LineString([source,target]); then I am trying to get the centroid of this lineString as lineString.getCentroid(). But ...
2
votes
1answer
33 views

finding the nearest point outside a series of geometries

I have db with a very large amount of geometries (circles), most of them overlapping. I'm trying to come up with a way to find the nearest point (from your current location) that is not within any of ...
1
vote
1answer
83 views

Is there a PostGIS function to get a tangent and normal line?

I'm looking for a function that will return a tangent (and normal) for a LINESTRING in PostGIS. I think this is the 3rd time I've come across the need for this function and everytime, I end porting ...
4
votes
1answer
339 views

How to calculate X and Y projected coordinate in batch processing

I have more than 1000 shape files (all are point features). They were initially in WGS 84. I projected them in UTM. Then through batch processing I added X, Y fields in each table. But all the X, Y ...
2
votes
1answer
155 views

Delete duplicate polygon nodes with PostGIS

I'm trying to delete duplicate nodes from a shapefile with QGIS, but after running the tool to delete it, nothing happens and shows the same errors. I thought that maybe importing to postgis could be ...
0
votes
1answer
44 views

ValueError when instantiating LineString from a mix of tuples and Point objects

I'm new to Shapely, and tried instantiating a LineString object from a mix of tuples and Point objects like this: >>> LineString([Point(1,2),(2,3),Point(3,4),(5,5)]) I get the following ...
2
votes
1answer
133 views

Removing last point in polygon geometry using ArcPy?

This polygon was created from a grid of 500 x 500 meters, then Union, Generalize and Dissolve was used to arrive at this geometry, the laspoint not help me, I just want to have points on each vertex. ...
1
vote
1answer
72 views

WKT: What is the reasoning behind the concept of a POINT EMPTY?

In data formats like WKT and WKB, we have ways of representing "empty" geometries. That all pretty much makes sense: a "LINESTRING EMPTY" is a LINESTRING type with 0 vertices. Same with a MULTIPOINT, ...
3
votes
3answers
95 views

How to display a table with more than one geometry column in QGIS?

In PostGIS, it is possible to use addgeometrycolumn more than once on the same table. Example: I have one table "scenes" with many attributes, and 2 geometry columns: the_geom1 and the_geom2. select ...