(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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1answer
129 views

Is it possible to draw polygons along Google Maps Polyline?

Web application has option that user draws polyline on Google Map. After he draws it, there is a button 'Add polygons', which should draw polygons along that line, based on some width and height in ...
0
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0answers
25 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 ...
-1
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1answer
22 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? ...
0
votes
1answer
314 views

SQL Geometry Query similar to Select by Centroid

Does anyone know if it's possible to query SQL geometry by something like 'centroid of polygon'...similar to ArcMap's select by location? I'm using SQL Server 2008 R2 as the DBMS. I have two polygon ...
2
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1answer
28 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 ...
0
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0answers
16 views

Hausdorff distance is too big for similar polylines [on hold]

I am using Hausdorff distance to compare two polylines as follows: library(rgeos) hdist <- rgeos::gDistance(mySpatialLines[1], mySpatialLines[2], byid=FALSE, hausdorff=TRUE) x11() ...
0
votes
2answers
190 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. ...
1
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2answers
79 views

How can i change the geometry of an existing layer?

I work with Qgis, v. 2.0.1. I have a point layer in which I have structures that could be represented as lines or polygons, but at the moment they are represented as a group of points. I know I can ...
6
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3answers
123 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), ...
2
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1answer
49 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 ...
3
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1answer
52 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?
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0answers
17 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") ...
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2answers
712 views

Why do I get wrong length using STLength on MultiLineString?

I have 2 MultiLineString representing the a route (first is driving there and the second is the return way) . MULTILINESTRING ((34.787315938035292 31.318235314177119, 34.788431415005249 ...
3
votes
2answers
101 views

Find gap in / endpoints of linestring

I have a set of features of type linestring. I'm trying to polygonise the linestrings and assumed that they were closed (naive me :) ). Of course some were not closed and I'm trying to locate the gaps ...
2
votes
3answers
293 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 ...
2
votes
1answer
126 views

How do I use code (preferably c#) to clip all points within a shapefile that are not contained within a polygon?

So the task is simple: I want to take a point shapefile as input and remove all of the points that are not contained within a polygon. I'm using DotSpatial to do this, but the catch is that there are ...
13
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5answers
2k views

How can one compare two geometries in arcpy successfully?

I am trying to compare two separate feature classes to identify differences between them (sort of a diff function). My basic workflow: I extract the geometries using a SearchCursor Save the ...
4
votes
5answers
837 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
42 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
133 views

How to perform SQL query using .STContains in MS SQL Server

I have a table that stores polygons and a table that stores points with a value field. Both sets of data are stored using the Geometry type in MS SQL Server. I have a simple requirement - I need to ...
0
votes
2answers
31 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 ...
1
vote
1answer
48 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 - ...
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2answers
91 views

How to disable “Simplify geometry” via Python?

After I've loaded a layer from a table in my db I'd like to disable the 'Simplify geometry' (found in Layers/Properties/Rendering) programatically using Python. I've tried several versions of ...
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0answers
28 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 ...
3
votes
1answer
160 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.
1
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1answer
171 views

Get geometry from OpenLayers.Control.WMSGetFeatureInfo JSON

I need to store the geometry of a certain feature with OpenLayers.Control.WMSGetFeatureInfo and i'm using these parameters to get it in json format output:'features', infoFormat:'application/json', ...
1
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1answer
40 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 ...
0
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2answers
135 views

Invalid geometry message when using Difference tool

I am using the Vector \ Geoprocessing \ Difference tool to get the resulting area when taking a) current ground disturbance away from b) historic total ground disturbance to give c) what has been ...
8
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6answers
1k views

Real-world example of Affine Transform?

From the Wikipedia article: In geometry, an affine transformation or affine map or an affinity (from the Latin, affinis, "connected with") between two vector spaces (strictly speaking, two affine ...
0
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1answer
110 views

Is it possible to have measurements in centimeter and decimeter in 2D flat (geometry)?

Is it possible to have measurements in centimeter and decimeter in 2D flat (geometry) for ArcGIS?
4
votes
1answer
83 views

how to compare geometries (contains, within) in arcpy?

I am trying to use 2 geometry objects to check if a line is within a (rather complex) polygon. The geometry check always fails, even if the line is clearly within the polygon. I use the following ...
0
votes
1answer
200 views

ST-Links convert Feature Class to DB Table error

I'm using ArcMap with the ST-Links SpatialKit Conversion tool to convert a Feature Class to a DB Table. But I'm getting an error: ERROR: 42601: type modifier is not allowed for type "geometry". I ...
35
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4answers
7k 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 ...
1
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1answer
297 views

SQL Data: How to draw circles with a radius based on lat/long data in DB

I have a . sqlite file with many columns, two of those columns being lat and long. I've been searching around for a bit now (don't think I want to be using BuildCircleMbr from spatialite?) but I'm ...
0
votes
2answers
44 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 ...
4
votes
1answer
371 views

Radius of curvature for curves in road segments for entire road network

I have a road network shapefile for a US state and I am trying to derive the radius of curvature for road segments in this shapefile. I need to be able to perform this task within just a few functions ...
9
votes
2answers
397 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 ...
3
votes
1answer
32 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?
1
vote
2answers
55 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 ...
15
votes
6answers
6k views

Converting between Esri Geometry and WKT using ArcObjects?

It seems like there is no means of converting an ArcObjects geometry to the Well-Known Text representation (and vice versa) in ArcGIS ArcObjects API. The only thing I was able to find is conversion to ...
2
votes
2answers
828 views

How to convert Geometry type column to degree Minutes Second in SQL Server 2008 R2

I have shape column of type geometry and I want to convert X and Y coordinates into Degree Minutes Second format using SQL query and i am using sql server 2008 R2. Currently I got Lat and long using ...
1
vote
1answer
65 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
102 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 ...
0
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0answers
43 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
vote
1answer
32 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 ...
1
vote
1answer
51 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
vote
1answer
35 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
votes
1answer
45 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: ...
1
vote
1answer
52 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
34 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 ...