Hot answers tagged

13

Answer: First, define a circle of radius 1. Then define an ellipse along x and y axis. Finally rotate the ellipse. EDIT: Finally, actually draw the ellipse Code: EDIT: previous code defined ellipse but didn't actually draw anything as asked from matplotlib import pyplot from shapely.geometry.point import Point import shapely.affinity from descartes ...


10

While arcpy Geometry objects do not support true curves, at 10.3, Esri implemented True Curves in the REST API, and therefore had to implement JSON support for them in FeatureSets. So you can "trick" arcpy into doing this for you if you create a curve in a JSON structure. Here's an example: create a JSON file with true curves (this uses a circular arc and ...


5

The Standard Deviational Ellipse from ArcGIS is not the only solution. In the geospatial world, there are two major algorithms (Yuill and CrimeStat III) and many intermediate solutions (QGIS: des Ellipses de Déviation Standard (SDE), un plugin, « Standard Deviational Ellipse », des scripts R (processing) et Python et une approche critique..., in French) ...


3

You could refer to Esri's documentation Creating an ellipse feature The Ellipse tool is used to create ellipse features. These steps can be used to create lines or polygons: To create lines, click a line feature template in the Create Features window. To create polygons, click a polygon feature template in the Create Features window. ...


3

I've done similar work before, for rotation, there is rotate function for polygons. In your case, add following line before adding feature to the layer: var originPoint = new OpenLayers.Geometry.Point(xCent, yCent).transform(map.displayProjection, map.projection); //center point for rotation polygonFeature.geometry.rotate(rot, originPoint); You can find ...


2

As noted by MappaGnosis in the comments - there is a tool for this in ArcGIS, called Table to Ellipse. Here is the documentation: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//0017000000tt000000 You will be able to tweak the values in your table and easily recreate the ellipses.


2

The SRID has been set already on your point. You need to transform the SRID, not set it, after you rotate it: SELECT ST_Translate( ST_Transform( ST_Rotate( ST_Scale( ST_Buffer( ST_SetSRID( ST_Point(0,0), 3395), 0.5, $6), $3, $4), $5), 4326), $1, $2)


1

The function above doesn't work perfectly because the scale and projection may distort the ellipse. Normally the coordinates are managed with WGS84 that is not a metric system so you have to convert the points in a metric system and then translate it again. First of all, you have to choose a metric system for your region. Here in Italy the best map system ...


1

Save a copy of your features (line/ellipse) as a backup. Then start an edit session on the target feature you want to rotate, then edit the angle of the feature. Preferably, edit the angle of the line (of the greater diameter) so that you can generate an ellipse of off that. This of course, will require you to calculate the angle difference between the ...


1

In your table of content put empty polyline feature class on the very top. Place your layer with curves underneath and run script. Original: Mirror: Script: import arcpy, traceback, os, sys, time mxd = arcpy.mapping.MapDocument("CURRENT") mirror=arcpy.mapping.ListLayers(mxd)[0] original=arcpy.mapping.ListLayers(mxd)[1] try: def showPyMessage(): ...


1

I don't know how you would automatically create an ellipse that contains 75% of your point layer. I would approach this task in this way: Create a grid layer or a custom polygon layer to overlay your point layer perform spatial analysis in qgis by using Vector -> Analysis Tools -> Points in polygon The procedure is similar to what is described as "Binning"...


1

We ran into the same problem when we had to draw hundreds of parcels from legal descriptions into a geodatabase. COGO tools were the only thing that would allow us to draw and retain true curves. Unfortunately, COGO tools are not scriptable. However, we were able to convert legal descriptions to txt format whereby we could then load them into the ...


Only top voted, non community-wiki answers of a minimum length are eligible