Tag Info

Hot answers tagged

8

In QGIS, many of the really good tools are in the processing toolbox; you need 'concave hull': Try it with different threshold values for different levels of detail: Finally, add a 10% buffer around the outside to make it resemble the sketch you provided:


7

Try Concave hull, What are Definition, Algorithms and Practical Solutions for Concave Hull? Concave hull has a smaller area, and most of implementations allows you to tune how small and precise resulting polygon should be.


4

The easiest way is to import your points into a format that can be queried with SQL, like PostGIS, SQLite or Shapefile (using OGR). Then you can query: SELECT * FROM [table] a, [table] b WHERE a.[featureid] <> b.[featureid] AND ST_Z(a.[geometry]) - ST_Z(b.[geometry]) >= 200; Or you can query and make lines in one step: SELECT ...


3

Here's a script that might do it for you. The native arcpy.Geometry class has a method called "cut" that will cut any feature using another polyline. Unfortunately, since you're using "points", we have to make "fake" lines out of these points. I essentially made a scratch polyline with the points [(Point.X+10, Point.Y+10), (Point.X-10, Point.Y-10)] - e.g. a ...


3

First you have to convert your polygon to lines. Then you can use Generate Near table. With this tool you can create table with few parameters (coordinates, angles) of nearest objects to your input objects. You can get this coordinates and create point layer if you need to visualise that.


2

Sounds like you are not aware of the tool points to line! The line ID would be your CULV_ID. Would PTID be the order of your points? Having used that tool to create the lines you would to write some code that reads for each ID and build the fields to transfer the information over.


2

(1) Use GME available from http://www.spatialecology.com/ (2) otherwise use the "Point distance tool" from the geoprocessing tools of ArcGIS - for proximity calculations to find the object distance in the same layer. You can specify search radius. I hope this will help..


2

To do this using linear referencing: Turn the line into a route. Use the points to add measures along that route as an event table. Then read the order of those points (now point events) in the event table from top to bottom.


1

There could be multiple approaches.Try this , Get the starting point of the poly-line feature Get the nearest vertex from the point feature Create an empty point feature class and push this nearest point into that perform 2,3 recursively for all points in the point feature class A clean and elegant way to get first point of a polyline is found in How do ...


1

You can use the open-source liblas tools for this. The command is, las2las --keep-classes 2 -i input.las -o output.las To do many files, use a loop. for f in *.las; do las2las --keep-classes 2 -i $f -o $(basename $f .las)_gnd.las done These commands are, of course, for linux, unix or OSX. liblas is also available for Windows through OSGeo4W.


1

With Fusion, the command line to be used is ClipData together with the switch /class. It can clip las data according to the return classification and within specific area of interest. The generic command line would look like this: ClipData /class:2 InputSpecifier SampleFile [MinX MinY MaxX MaxY] /class:2 is because the required category is ground, which ...


1

I used SAGA for the evaluation of my LIDAR data and some easy processing. Go to tool libraries > Import/export > LAS. When you import the LAS data using Import LAS Files you can select the import of existing classifications (this should be your categories). Unfortunately, my LIDAR data don't have categories so I can't try it myself. You can select points ...


1

lasground.exe in the LASTools mentioned above. This can be run from command line prompt very cleanly.



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