Questions tagged [geometry]

(1) abstract geometry; (2) storing geographic data in projected coordinates; (3) a generic ESRI term for vector features; a class for "geometry" objects.

191 questions with no upvoted or accepted answers
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134 views

Split Polygon Layer by other Polygon layer in QGIS

I know there is a lot of previous posts to this subject, but I simply cannot find the solution I am after in the other posts. I have to following problem: I have two very extensive polygone layers, ...
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134 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( ...
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242 views

Reverse parameters of a projection map / guess which geographic project is used

I'm user of a soaring simulator named "Condor Soaring". This simulator is at the center of a community of enthusiastic people who build sceneries (landscapes) which represents quite accurately real ...
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834 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 ...
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577 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 ...
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1k views

Invalid geometry

I'm working on some shapefiles in both ArcGIS 10.2 and QGIS 2.0. I have 3 files which I have cleaned of self intersections in ArcGIS using Repair Geometry. I have also checked for Overlaps using the ...
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145 views

Geoprocessing operations re-introduce geometry errors after “repair geometry” succeeds

I am working with a shapefile that has many small, detailed polygons. After exporting it to a feature class in a geodatabase, I found that some operations (for example, Snap in the Editing Toolbox) ...
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87 views

Critera for geometry or geography

What criteria do you need to take account to before you choose geometry or geography map? Is there a book or page about it?
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263 views

how to convert lat and longitude into distance near poles?

I am trying to convert latitude and longitude into meters in polar regions. I am looking for higher accuracy upto 0.00 meters preferably. I tried the haversine formula but it doesnt seem to be ...
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419 views

ArcGIS/arcpy: Geometry object comparison methods not working. Do they take z values into account?

I have an arcpy script that makes calculations based on an input PolygonZ feature class. What I need to do in several places in the script is test whether a point falls within a polygon in 2D. In ...
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17 views

Zoom to extent using geom or xmax, ymax?

I made a function to zoom to polygon geom if I click the button. This is my script: $.ajax({ type: "POST", url: 'core/zoomtolocation', data: { ...
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65 views

Selecting geometry from PostGIS compatible with Open3D

I have a cube stored as geometry in a PostGIS DB. I get the coordinates using the following SQL: select ST_AsEWKT(geom) from polyhedral.vol_1 where id = 1 This presents the following result. ...
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38 views

High cost of geometry bitmap heap scan

I have a PostGIS database with tables osm_admin (with contains all administrative boundaries from osm data) and osm_landusages (with contains all landuse areas form osm - like forests, industrial/...
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20 views

When exporting shapefile I added polygons to I get an error

I was tasked with updating a map at work and had to add a number of polygons to the layout. I did this by creating features and then just selecting polygon or autocomplete polygon and just drawing ...
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36 views

Identifying convex and concave portions of polygon using ArcMap

I have a polygon shapefile depicting an island. For my study, I'm interested in two coastal features of the island: convex sections (portions of the coastline that extend into the ocean) and concave ...
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22 views

PostGIS - Measuring the angle at the touching point of two lines

I want to calculate the angle of two lines of a routing network exactly at the "touching point" (the topological vertex). My previous attempt was using the ST_ANGLE() function of PostGIS, which gave ...
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33 views

How can I easily determine the precision of an OGR geometry?

I'm writing a python tool to update some river catchment boundaries and keep running into geometry errors, such as WARNING: TopologyException: Input geom 1 is invalid: Self-intersection at or near ...
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33 views

QGIS: Update geometry via geom_from_wkt('POINT(X,Y)') - how to correctly parse string columns?

The columns containing X and Y strings look like -1234,56 So far i tried: geom_from_wkt(concat('POINT(',replace("wbr_komplett.X",',','.'),',', replace("wbr_komplett.Y" ,',','.'),' )')) and also: ...
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27 views

Creating planar rectangle about points of interest in Google Earth Engine?

If I have a list of points of interest in Google Earth Engine, e.g. var pointList = [ ee.Feature(ee.Geometry.Point(-73.96, 40.781)), ee.Feature(ee.Geometry.Point(6.4806, 50.8012)) ]; var ...
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55 views

Pros/Cons of using 'ellipsoidal' for calculating geometry in QGIS?

When I have found geometry attributes in the past, I've found my distances are often out by quite a lot unless I use an ellipsoidal CRS to calculate them. Why is this the case? Should I be using ...
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1answer
33 views

Measuring area covered by linestring

I have a trajectory given by GPS which I store as a ST_LineString() and I'd like to know the area covered by the line string. I know the "width" of the trajectory, but I'm not sure how to approach the ...
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1answer
83 views

Problems with dissolving layers [QGiS 3.4.1]

I am currently working on a set of data that defines restricted areas for use of photovoltaic modules. This set of data amounts to 270.00 polygons in total [with their own geometry]. For simpler ...
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1answer
17 views

Splitting lines: Options for managing IDs and related records

I have roads in a feature class (Oracle 10.3 geodatabase). Roads are split into separate lines where they intersect. This is an established business rule that cannot be changed. Each road has ...
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92 views

SQL Server spatial data geometry type

I'm trying to link a GeoServer application to a SQL Server Spatial Database. The spatial data has been saved as Geography, but GeoServer can read only Geometry type. So I'm using the following script ...
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21 views

Editing errors in shapefile

qgis version: 3.4.9-Madeira I am editing a shapefile. I want merge two adjacent polygon. Then, I run merge tool, and it comes like below picture. You can see some gap(?) or tail shape line between ...
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44 views

Find closest points using S2, given point and radius

I'm trying to use the go s2 package to find closest points, given a point and a radius (meters). I'm modeling my alg. after dynamodb-geo.js as I'm storing my points in DyanmoDB. I can't seem to get ...
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28 views

Solid is invalid : PolyhedralSurface (shell) 0 is invalid: self intersects

I am trying to calculate the volume of an object with geometry type --PolyhedralSurface. ST_MakeSolid(geom) is valid, while ST_Volume(ST_MakeSolid(geom)) is invalid for the following reasons: ...
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0answers
50 views

Spatial operations between WMS geometry and client data

I am using geoserver WMS service to visualize some geometry on the map (via Leaflet) which is working fine. Now I have a requirement to perform the spatial operation (say intersects) between two ...
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0answers
40 views

What could cause a Spatial Join (Completely Within) to return false positives?

Im using ArcMap 10.3 I have a large feature class of Archaeological surveys that I need to Spatial Join to a target feature class of buffered work locations to find locations that are Completely ...
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0answers
38 views

Identifying geometry format?

I have a database with geometries encoded in a field in the following format: '1 L 410012.85,416177.69; +30.16,4; 12.46,0; 13.35,-0.67' Where L specifies that it is a Polyline, then 410012.85,...
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0answers
25 views

Feature geometries sometimes treated as equal, sometimes not (PyQGIS)

QGIS 3.4x64 and Python 3.7 seem to sometimes treat my geometries as equal, sometimes not. I'm debugging code using a reduced dataset with 3 points. Points A and B have the same geometry, and point C ...
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0answers
191 views

Problem importing geometry from CSV in QGIS

I have a polygon layer (although I have also converted it to points and tried it that way). I would like to copy this layer into excel and add it back in after editing some things. I've attempted to ...
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129 views

What is geometry(4326), and can you do Cartesian calculations with unprojected ellipsoidal coordinates?

I know Geography(4326) is an unbounded, and unprojected, and covers the entire world with ellipsoidal coordinates. I get that the math on this system is done on a spheroid. I also get that with a ...
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1answer
641 views

Create geometry from point data - QGIS 3.4.1

Is there an efficient way to produce geometry from point data using QGIS? Each point represents a feature that may require one or more geometric primitives such as circles, curves or polylines (open ...
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1answer
54 views

Add geometry line to the map

I'm trying to test the code example on the page http://docs.geotools.org/stable/userguide/tutorial/geometry/geometrycrs.html I copied this example into eclipse Transaction transaction = new ...
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1answer
252 views

Converting multiple geometry KML to Shapefile

I have a KML file with multiple geometry, points and polygons. I want to convert it to a point Shapefile and a polygon Shapefile. Using OSGeo4W Shell I tried this : ogr2ogr -where "OGR_GEOMETRY='...
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0answers
16 views

Points on the opposing side of a breakline

If you have a breakline or even a single line segment within a DEM, how can you tell if two points lie on the opposing side of that breakline or line segment? From a computational geometry standpoint ...
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0answers
33 views

PostGIS: Get portion of length in polygon. Aggregate value by this portion

I have a table that has two points (made into a line) and a value per row. I have another table that is a grid that has a geometry and id per row. I'd like to aggregate the data in such a way that ...
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0answers
371 views

draw centerline of road polygon in python

I'm trying to draw a center-line of this road element but I'm not able to make it with the PostGIS function ST_ApproximateMedialAxis() Also tried the python centerline library but it giving me error ...
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0answers
45 views

Seeking automated approach for categorising roads according to their designs using QGIS?

I have a shapefile comprised of polylines. The road segments are represented by lines that are between nodes. I want to categorise each road segment accordingly as they appear either as a straight ...
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0answers
88 views

Transform GML to Geometry (PostGIS) in GeoKettle

How can I transform GML (saved in XML file) to Geometry type? I've noticed function 'Geometry from GML' in Calculator but it needs string value with GML. Is there any way to extract it from XML file?...
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0answers
39 views

how to Input polygon featuer using Rubber poly (ArcObjects)

Does any one know how to input polygon feature using Rubber poly? I would like to know how to input Polygon featurer using rubber poly.. as of now i can input polygon feature. but some times , polygon ...
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0answers
2k views

Add Geometry Attributes doesn't work for feature classes but does work for shapefiles

I'm trying to add start and end point coordinates to a line feature using the LINE_START_MID_END geometry property of the Add Geometry Attributes tool. Every time I use the tool on a feature class in ...
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0answers
110 views

Creating points from a one to many relationship

I have created a one to many relationship within a geometric shapefile. Is it possible to to create points from the 'many' records in this shapefile as I would like to output the records into a ...
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0answers
533 views

Checking geometry validity

I'm using QGIS 3.0 and I have a problem with checking validity of the geometries of a shapefile. I imported a DXF, converted the polylines into polygons, manually corrected the wrong or intersecting ...
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0answers
102 views

Invalid geometry -

I have polygonised a viewshed and as a result, I have small 1x1 holes on the perimeter of the output which has created overlapping nodes (although the node tool does not pick up on it). The screenshot ...
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1answer
268 views

Finding point of intersection between: a line segment of two LatLngs, and a line with initial point and bearing

I have a line segment AB made up of two LatLngs, A and B. I have another LatLng C and a bearing x degrees. How can I calculate the point D where a line from C with bearing x degrees meets the line ...
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0answers
70 views

Change attributes' values based on geometry relation

MY GOAL IN A NUTSHELL I am trying to calculate the angles between lines. For doing this, I calculated the lines' slop respect to x axis and now I am trying to subtract them to find the angle inside. ...
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0answers
188 views

Calculating geometry size as a circle, and combining that data

Given a way geometry (from OSM), I would like to convert them to "circles" - a center point + radius guaranteed to contain the whole object. Plus I would need a set of functions to perform various ...
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0answers
286 views

Combining touching polygons

PROBLEM STATEMENT I am trying, based on previous posts in this website, to combine polygons within the same layer but just when they touch each other by means of pyQGIS. It doesn't work (proper ...