XYZ file terrain modeling


#81

@thomas.engel’s XYZ data is in nice orderly rows (rasters) and columns like a 2D image. Extending the image analogy by giving each pixel a gray-scale “depth”, height maps essentially provide the same information.

You may, indeed :wink:

I think that the accuracy is dependent on the original input datum points. Whether it is rasterized or vectorized, the result is still just an approximation of the real world using best-fit algorithms through the dataset.

The Grand Canyon model I indicated in a previous post was made from 1/3 arc-second (~10 meter) data from the nationalmap data source. There is also some 1/9-arc-second data available for certain areas of the US (Boulder, CO, for example). This is about 3.4 meters of resolution. There is also 1-meter data available in Erdas IMG file format. The most accurate data seems to be obtained by low-flying planes using LIDAR or other sensing schemes. Personally, I find it frustrating that I can’t simply download an area at 1mm resolution to get a really high-res definition :frowning:

As you know, this gets more complicated when translating between the various planar, cylindrical, and spherical coordinate systems that have been used in one context or another. The OP’s XYZ data uses a perfectly rectangular grid to map a portion of a spherical surface. It also specifies the elevation in meters to four decimal places. This implies a precision of 0.1mm in the vertical axis(?). For more precise work, I think that site scanners (such as Trimble makes), are the most accurate solution by their very nature. However, at the end of the day, it all comes back to some sort of interpolative manipulation of the point cloud to accurately depict the real world.


#82

The data I used has an accuracy of +/-25cm, that is +/-0.82feet - anyone answers to my questions raised today in the morning hours?


#83

I would export the Mesh as a Collada File (*.dae)


#84

Q re selection moved to new thread.


#85

Hi jimhami42,

I tried using Thomas Import, but nothing happens.
I am trying to import a txt file with content like this:

x,y,z
-21061.0320,9602.0660,36.7640
-21055.5230,9599.3110,37.5180
-21056.5310,9598.7640,37.2790

What could be the problem?


#86

The Thomas Import was written specifically for the formatted data Thomas had available. It’s separated by spaces, not commas, and takes advantage of the ordered data:

image

If you can share more info about the x,y,z data you have, I can maybe help you get it imported.


#87

Hi Jim,

thank you for the reply.
It’s survey points from a piece of land where a house will be built. I want to import the points into SketchUp to make a surface out of them. I then want to use this surface to cut a solid which represents the foundation of the house. The volume of the solid which gets cut away corresponds to the volume of boulder which has to be removed.


#88

@bleikur

This can be done in SU. It would be really helpful is you upload the pont data set or at least a portion of the data set so we can have a look and determine your next steps.

CD


#89

Hi Chris,

thank you for the reply. Here you can see the whole point data set.


#90

Hello my name is Pierre
I have done a 3D model of a coffee counter on sketchup and I am trying to insert pics of coffee machine from warehouse on to my model but can t manage to do so.
Anyone can help?


#91

I created a simple plugin for you to import these survey points as “C-points” (guide points) into SketchUp.

https://sites.google.com/site/spirixcode/code/bleikur_import.rbz

The units are assumed to be in inches. Once imported, you can use the tape measure between any two known points and re-scale everything to whatever you need. This is what I get from your data file:


#92

Thanks a lot, Jim. Much appreciated.
Now I just have to figure out how to create a surface from the survey points. :grinning:


#93

One feature in Fredo’s TopoShaper extension can convert guide points into a terrain.


#94

Hi Chris,

thank you so much. I will give it a try. It looks as if TopoShaper creates a solid with a calculated volume, which is exactly what I need.


#95

It does create a skirt but it is a separate group. You can merge it with the terrain above to make your volume. :slight_smile: