(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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36 views

Convert string column back to geometry column?

I had a table with a column set to 'point' in doctrine2, but this was changed to 'string' and updated. I can't change it back to 'point' in doctrine2, I get an error: ...
2
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1answer
54 views

Geometry in QGIS 2.6

This might be a beginners question, but I could not find an answer on the internet. I drew a couple of polygons in a vector layer and I am trying to get some basic geometric information into my ...
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2answers
28 views

Postgis: Query ST_DWithin in square instead of circle

The ST_DWithin query queries all geometries within a certain radius from another geometry (in my case a point). For performance optimization of my application I want to query in a square. So that the ...
2
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1answer
68 views

How to handle coordinates accuracy in ArcGIS

I am creating very basic rectangular polygon using very basic a Python code nCols,nRows=100,100 corners =[[0,0],[0,nRows],[nCols,nRows],[nCols,0],[0,0]] ...
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1answer
22 views

problem in PostGIS Name of the system used for Points and how to get distance between to point?

I have started to work on a project in PostGIS. I have a table with a geometry points in which points saved like this : "010100000089F511C671C01E4162327E2A83545341" and I have translated this ...
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1answer
30 views

Parsing large GeoJson geometry to WKT

I'm reading a very large json file as an InputStream in Android with JsonReader. This json has a geometry object like so.. "geometry":{ "type":"MultiPolygon", "coordinates":[ ...
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0answers
11 views

postgis 2.x geometrycollection and multi

I want to gather differents geometries in a table. So I transformed a multipolygon geometry in a geometrycollection. Now if I can insert differents geometries, I lost the capability of insert ...
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0answers
19 views

JTS Geometry to GML3.1 encoding

I searched all the internet and I didn't find a solution to my problem. I want to convert a JTS geometry to a GML3.1 geometry. Geo tools says that have support but the have not (please check encode ...
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0answers
34 views

Convert java.vividsolutions.jts.geom distance to meters

I am using com.vividsolutions.jts.geom to perform the distance calculations. I have a list of "LineString"s and a Point (Say A). I want to determine the The nearest LineString to the Point A. The ...
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0answers
17 views

Creating density layer after calculating one value based on two variables?

I have a map of census blocks and the population of each block for an island. I also have a map of the tax map key (TMK), broken down into land parcels, with the dollar value of each land parcels. I ...
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1answer
51 views

ArcGIS geometry update from table XY

I am trying to update the geometry of a point FC stored in a FileGeodatabase using ArcPy. I got this Python script to compare the values of the SHAPE@X and SHAPE@Y and change the Geometry if not ...
4
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1answer
46 views

Calculate distance from all points to all lines within 10km using FME?

I have a polyline shapefile and a point shapefile. The points are along the polylines. There are over 100 lines and over 10,000 points. I want to calculate the perpendicular distance from every ...
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0answers
33 views

Inflating the boundaries created with convex hull

I have a set of lan and lat points and have plotterd a convex hull for them using QGIS. A polygon is created along the set of points and plotting them on the MAP. Now I am trying to inflate the size ...
6
votes
1answer
284 views

How to compute Straight Skeletons using Python?

Is there a Python package which provides an implementation of a Straight Skeleton algorithm? I'm aware that the open source (C++) project CGALcontains an implementation but it seems like ...
1
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1answer
63 views

Openlayers 3 ol.extent to ol.geom.Polygon conversion

In openlayers 2 there was a method "toGeometry()" on Openlayers.Bounds() that could convert that bounds into a Geometry. I migrated from ol2 to ol3 and I try to find a solution to easily do the same ...
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0answers
90 views

C#, SQL Server Spatial Functions: Convert Polygon's Lat Long ESRI Polygon Values?

I have a C# program which parses a .kml file and reads polygonal Shape field's data and then does sql inserts to a SQL Server database. The value of the final_coords variable in code below is: ...
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1answer
29 views

How to use Calculate Geometry tool to calculate area

I have added a field in my attribute table but I cannot calculate the area. The units field is greyed out and the options at the top say "area - disabled". What can I do about this?
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1answer
17 views

Points shapefile resulting in MultiPoints table in PostGIS

I have a Points shapefile. When opened with QGIS, the type is 'Point' (right-click on the layer and check properties). When imported in PostGIS using pgAdmin III plugin 'PostGIS shapefile and DBF ...
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1answer
21 views

Is there any way to know if a polygon is part of another bigger polygon(s) in SQL server?

Basicaly, what I am trying to do is we have a lot of geographical containers like territories, sub-territories etc. and the boundaries of each keep on changing all the times and I have to store the ...
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2answers
80 views

Intersection point of polygon and the line created by two points ArcPy

I have polygon layer. I selected the most distant vertex from centroid (picture: point A). (How to do that is in the answer here: Select the most distant vertex from polygon's centroid using ...
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2answers
120 views

How to calculate the Oriented Bounding Box (OBB) of a polygon or point set?

I'd like to calculate the "Oriented Bounding Box" (OBB) which is the enclosing rectangle aligned to the longest extent of a point set (which is not necessarily aligned with the axes of the co-ordinate ...
4
votes
3answers
117 views

Select the most distant vertex from polygon's centroid using ArcPy

I have a poligon and the polygon's centroid. I want to select the most distant vertex from centroid (picture: point A). I used arcpy.FeatureVerticesToPoints_management to create a feature class ...
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2answers
82 views

Order sql server spatial geometry distance by the nearest

I have a geometry column in a table, I want to get the N nearest neighbours; here is a specific example with the geography type DECLARE @PTO Geography = Geography::STPointFromText('POINT(-57.432546 ...
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1answer
49 views

How to choose a SRID and what is its meaning? [duplicate]

I'm new to GIS, in PostGIS, and I'm struggling with the SRID concept. How do you choose a SRID for a database column? This is making me crazy. Why do I need to choose a SRID? What's its meaning? ...
2
votes
1answer
43 views

Difference between: join, merge and group

Suppose it is desired to make polygons A and B, and their respective attributes to be one unique polygon C. What is this GIS operation called? Is there any difference in GIS terminology about ...
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0answers
52 views

How to choose data type and SRID, for coordinates from different sources, in a medium size zone

I'm developing an application. In the database I need to store coordinates for many places, in the north-east of Italy, but the area could expand in the future. This coordinates will come from some ...
6
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3answers
202 views

How to measure similarity of SpatialLines objects

I created two SpatialLines objects in R: . These objects were created this way: library(sp) xy <- cbind(x,y) xy.sp = sp::SpatialPoints(xy) spl1 <- sp::SpatialLines(list(Lines(Line(xy.sp), ...
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1answer
27 views

oracle VectorLayer without geometry - How to get attributes?

I have a prolem to iterating over a oracle VectorLayer without geometry in QGIS 2.6. self.uri = QgsDataSourceURI() self.uri.setConnection("localhost", "port", "xe", "name", "password") ...
3
votes
1answer
54 views

How Does One Calculate Angular Defect?

If I were to draw a 1km square on the earth what would the angles of the corners be? Obviously they would be a little greater than 90-deg but how would I calculate the angle exactly?
2
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1answer
54 views

Python library for geometrical calculations using with GRASS GIS?

I have to do some geometrical calculations in 2D(point, lines, line segments and intersection points) in Python, and then use it in GRASS GIS. What is the best library to use for it? I'm trying with ...
0
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1answer
76 views

Getting GPS coordinates perpendicular and parallel to AB

I already posted this question here And I got the solution thanks to Fang but the problem is that the coordinates I need to use are GPS coordinates and apparently GPS needs a different formula than ...
1
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1answer
56 views

Cover a polygon with fixed size squares

Can you please advice me of an algorithm (which I can implement in a Java) to cover some polygon (not exact cover) with squares of certain size (aXa squares)? The cover doesn't have to be exact - ...
1
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1answer
79 views

How to create postgresql triggers to calculate geometry from x,y and vice versa at the same time

I have a postgis table with point geometry which looks like this CREATE TABLE mypoints ( gid serial NOT NULL, coordid integer, geom geometry(Point,4326) ); And a table with coordinates ...
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2answers
54 views

add featureset in graphics layer without iterating

I have a geoprocessing service that returns a large amount of features (featureSet). I want to attach them in a graphics layer, but I dont wont to iterate over all them. I tried using the ...
3
votes
1answer
34 views

How to save shape file as type 1 point file in Qgis?

QGIS saves point shapefiles as type 8 - Multipoint as default. I need QGIS to save as type-1 Point file. How?
0
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2answers
89 views

MS Sql Server 2012 UnionAggregate geometry fails in ArcMap

I have following two geometries. Geometry 1 (G1): MULTIPOLYGON (((148.134707676 -34.1519003565, 148.143738823 -34.1540810687, 148.14648294 -34.1396863245, 148.143196834 -34.1392361445, 148.140859243 ...
1
vote
2answers
112 views

Ensuring SRID on geometry column in PostGIS

I am using a table that has a geometry type column called "wkt". Its definition in the table looks like this: create table sometable ( ... wkt geometry not null, ... ); I want to change it ...
2
votes
1answer
107 views

ArcGis label last vertex Z value

Is it possible to label a feature in ArcMap using geometry values? In this instance I want to label features (polylines) with the Live Z value of the last vertex obtained from the Shape. However ...
2
votes
1answer
113 views

QGIS crash when I try print geometry

I do (it works): from osgeo import ogr inputds = ogr.Open(r'c:\temp.shp') inputlyr = inputds.GetLayer() for i,feature in enumerate(inputlyr): print i, feature.GetGeometryRef() Output: 0 ...
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0answers
80 views

Array to Feature Class and XYZ to Table Issues

I am trying export vertices of a line to a point feature class using the code below. I am using ArcGIS 10.2.2 and do not have access to Spatial, 3D, or Network analyst. I used ET GeoWizards to export ...
1
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1answer
70 views

How to save changes in Feature-Geometry with GDAL/OGR and Python? (Segmentation fault)

I have a problem with my code: driver = ogr.GetDriverByName('ESRI Shapefile') dataSource = driver.Open('merge.shp', 0) if dataSource is None: print 'Could not open file' sys.exit(1) layer = ...
1
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1answer
38 views

Why are my points offset when using the Go to XY tool?

I am creating points in ArcGIS 10.1 to add to a GPS so I can navigate to them in the field. I add my points by editing an empty shapefile created in ArcCatalog. I then Add Field: Lat and Long as ...
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1answer
43 views

Defining polygons based on thickness maps using ArcGIS for Desktop?

I want to find and create polygons that demarcates three different inflection points in a thickness raster: where the thickness start to increase, where the thickness is at its max and where it starts ...
0
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1answer
65 views

Convert geography to geometry in H2GIS?

In H2GIS, geometry can be converted to geography with function "ST_Transform" For example: SELECT ST_Transform(ST_GeomFromText( 'POINT(584173 2594514)', 27572), 4326); -- Answer: ...
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1answer
64 views

How to calculate distances in QGIS field calculator?

So I'm using qgis 2.6.0 and I have a csv (converted into a .shp) with two geometry columns, I want to create a new column with the distance between the two geometry: shot.lat shot.lon haul.lat ...
0
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1answer
49 views

Adding geometry.type circle

I have to amend the following code so that on the map it's possible to draw a second circle graphic as well as a line, polygon and point. I've tried to add an else if statement much like the polygon ...
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0answers
29 views

Metrics of change between vector datasets

I have an old and a new set of parcel data which I'm looking to compare. I'm looking to compare changes in individual parcel geometries, so boundary/corner adjustment. Currently each parcel we have ...
2
votes
1answer
104 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
90 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 ...
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1answer
32 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 ...