Hot answers tagged

19

Use the "Feature Vertices To Points" tool within ArcToolbox or if you do not have ArcInfo license then you could use the Polygon to Point tool from ET Geowizard (free tool), then in ArcMap you can use the "Add XY Coordinates" tool to get the XY value for each vertex.


14

In the OGC specification, which can be downloaded [here],(http://www.opengeospatial.org/standards/sfs) they state: "Polygon rotation is not defined by this standard; actual polygon rotation may be in a clockwise or counter-clockwise direction." In SQL Server Spatial, the geography datatype follows a counter clockwise rule for the outer-ring, and ...


13

There are many algorithms to solve this problem (Wikipedia "Convex_hull_algorithms"): Gift wrapping aka Jarvis march — O(nh): One of the simplest algorithms. It has O(nh) time complexity, where n is the number of points in the set, and h is the number of points in the hull. In the worst case the complexity is O(n2). Graham scan — O(n log n): Slightly more ...


13

I often refer to the ESRI GIS dictionary in these cases. Based on these definitions, nodes have topology whereas vertices do not. Vertex: [Euclidean geometry] One of a set of ordered x,y coordinate pairs that defines the shape of a line or polygon feature. Node: [ESRI software] In a geodatabase, the point representing the beginning or ...


8

Ring (boundary) directions are needed to prevent ambiguities for geographic coordinate systems that cover a finite surface, since the boundary would define two areas, one left and one right of the boundary along it's direction. Determining which of those two areas is the bigger one is possible, but still leaves the ambiguity. Here is an overview on outer ...


8

In order to solve your problem: Create a FileGeodatabase In the FileGeodatabase create a FeatureDataset Import the shape in the FeatureDataset In the FeatureDataset create a Topology In the wizard choose next and in the Rules page click Add Rule Select "Must Not Overlap" or "Must Not Have Gaps", check "Show Errors" and click OK. Complete the wizard and ...


7

Apparently, the ArcGIS Idea to Delete Multiple Verticies [sic] was implemented in ArcGIS Desktop 10, so as long as you are using that version (or later) you should be able to use it.


7

There is a sample toolbox which includes a Write Features To Text File python script which: Writes feature coordinates to a text file. Note: Technically, the tools in the Samples toolbox have been deprecated. They are still installed with ArcGIS so that any existing script or model tools you developed before 10 continue to work.


6

1)Convex Hull in GRASS GIS: http://grass.fbk.eu/grass64/manuals/html64_user/v.hull.html 2)Convex Hull in Qgis Vector Tools (very easy to use):


6

To display more, go to editor -> options -> general tab in Arc 10.


6

My high level, and easy to remember, "definition" would be ... Nodes are vertices but only two vertices are nodes i.e. those that start and end a line. Nodes can be sub-classified into those which are: Dangling i.e. share their precise X,Y location with no other nodes Pseudo i.e. share their precise X,Y location with only one other node True i.e. share ...


6

We are discussing a particular form of vector representation of objects in a GIS. Such objects are the continuous images of homogeneous simplicial complexes: points, multipoints, polylines, multiple polylines, (triangulable) polygons, collections of such polygons, and "TIN"s. A simplicial complex describes two conceptually different things, albeit ones ...


6

No need to create a new layer. You can show your layer's vertices using the Outline: Maker line Symbol layer type. Just add a new symbol layer Add a new symbol layer; Choose Outline Maker line (top right corner); In the Marker placement, Choose "On every vertex" You can even style the marker to look like the red cross symbol used on layers in edit mode. ...


5

This works with a standard ArcGIS license: desc = arcpy.Describe(fcl) shapefieldname = desc.ShapeFieldName gebieden = arcpy.UpdateCursor(fcl) for gebied in gebieden: polygoon = gebied.getValue(shapefieldname) for punten in polygoon: for punt in punten: print punt.X, punt.Y


5

Once you have the Polygon, QI to IPointCollection. You can then iterate over all the points in this PointCollection which are the vertices that you need. Here is some code which shows how to get the selected features & then get the geometry: I am writing this from memory, so it might not be exactly correct, but should give you an idea Dim ...


5

What licence level is your ArcMap? Intersect should work with a set tolerance. http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00080000000p000000.htm should create a new polyline with nodes where your vertices were. You will need to rebuild your network afterwards


5

Those lines and vertices are actually holes or islands on your polygon. Try using the delete part or delete ring tools in the advanced digitizing toolbar, and click on one of the nodes. I have noticed that sometimes you need to drag one or more nodes a bit to be able to click on the hole\island boundaries to delete it. Hope it helps.


5

You can use the Select (Analysis) tool to select a subset of features based on a SQL expression and export the selected results to a new feature class. In this case, I used the following expression: SHAPE_Area > 100 Alternatively, you can perform the same action directly on the attributes using the following workflow: Open attribute table > Select ...


5

The key is the difference method on geometry objects. The following code is far from efficient, since a new update cursor is opened for each polygon. But it has the added benefit of supporting multiple polygons on the same line: import itertools, arcpy arcpy.env.overwriteOutput = True line_FC = r'<path to lines>' poly_FC = r'<path to polygons>' ...


5

Here's a very simple approach that offloads all the processing into the Sort GP tool. Since you have access to an Advanced license, sorting by shape and starting at the lower left corner gives quick results. import os, arcpy arcpy.env.overwriteOutput = True inFC = r'<path>' outFC = r'<path>' # create output FC to hold points and field to ...


4

In ArcMap, open the Attribute Table of the feature class in question. Go to the field properties by right-clicking the column heading of the fields in question (one at a time) and selecting Properties Click the box that looks like this [...] next to Numeric and set the rounding.


4

It sounds like you are working with polygons. I created a 4-corner polygon in a FGDB, and when I look at it in the editor, it does have 4 vertices: However, when I run the following script on it, you can see it does indeed have 5 vertices (as it should), where the first and last are the same in order to close the polygon: import arcpy infc = ...


4

AFAIK, the most simplest and fastest way is edit geometry with vertex level. Polyline is collection of Points and you can edit points and replace it. In this case, rotate each vertex with pivot anchor point, and interpolate new z value. then replace original points to these rotated points. So the code will be like this, //sample: pivot index is 3, radian is ...


4

I don't know that anybody will be able to provide a definitive answer for your question since each vector file format is different and each GIS, in terms of how they internally handle these data, will also be different. But I can tell you for certain that the clockwise ordering is not only for ESRI Shapefiles. There are other formats that use a similar ...


4

You can try Feature Vertices To Points tool to extract start and end points of a polyline then apply this tool Station Lines Arc10.0, to generate perpendicular line along these points.


4

Given the examples of the rectangles and parallelograms, and if I'm understanding your formulation of "lower-left" (i.e., "the most south-west") correctly, a naive solution: You could sort the four vertices in order of ascending latitude(i.e., the south-most is first, north-most is last). If two are equal in latitude, their sequence doesn't matter. Then, ...


3

There is a great chapter in concept and samples explaining editing in ArcGIS Engine: ArcGIS Engine editing and How to work with the snap environment


3

You can use Snap (Editing) tool from ArcToolbox. It can be found in ArcToolbox\Editing\Snap. Set inaccurate polygons as Input features and accurate points after post-processing as Snapping Environment. Also set reasonable Distance parameter for points. Result of my testing the tool: This tool is only available with ArcEditor and ArcInfo licenses.


3

Try the geo-wizard tools fron Spatial technologies. It has several free tools that can do what you want. Try the get polygon coordinates. Or polygon to points et geo-wizards


3

Hawth's Tools for ArcGIS has this functionality. Plus a script for ArcInfo 10. There is also convex hull tool in QuantumGIS via ftools plugin.



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