Survey of Geospatial uses in SketchUp

miikka1978

Thanks for your comments/suggestions Ryan and Chris!

The original terrain information that I have is actually xyz-file. Anyway, it includes over 700 000 points. After cropping the area into required 3000m x 3000m area I still have over 90 000 points. Therefore, I used qgis to create contours from xyz-file. I decided to export the contours including the height label as tif-file and now am tracing the contours in Sketchup. If I remember correct, there was some statement that Sketchup can handle max 5000 - 8000 points. One solution could be to reduce the number on xyz-point in the file, but I haven't found any efficient way for deleting the points in Excel or some other software.

ryangarnett

miikka what format do you have the xyz file in in QGIS. If you convert it to a point shapefile you can use some of the random sampling tools in QGIS. Within the Vector tab, under Research Tools you can use the random sampling tool, which will allow you to select based on a number of features, or by percent of features. You could use this two ways:

to select features to export to a new file
to select features to delete from the current file

GISdude

Ryan/Chris,
I'm still getting my feet wet in SU. I'm trying to create contours in SU, either by bezier curves or splines or something. I still can't figure out how to populate the z-values. This is SF Bay (hunter's point), and I've been to the site before and I can "ground proof" the elevation. Seems to me that this should be very simple because you can toggle the terrain - so it seemed to me that their is underlying planimetric data that comes with the program.

Pardon me for my terms, but I'm an ARCGIS/AutoCAD guy and the 3D world is still kinda new to me.

Thanks for any help,

miikka1978

Thanks for the instructions Ryan.

I managed to save the xyz-file as shapefile in QGIS and reduce the number of points. Also, I finally managed to import the file into Sketchup and create the terrain with Point Cloud Plugin.

One question, is there a way in QGIS to choose points regularly before deleting them. Now I have been using Research Tools / Random selection, which produced ok results. But, it would be even better to be able to remove points regularly/evenly.

ryangarnett

Hi GISDude,
The best way I have found to make contours for SU using geospatial data or info is to make DWG files as contours. This has been a multi step process for me. In some cases I have made contours from a DEM. In other cases I have had contours and needed to modify them. In all cases I have had to convert the contours to 3D z-enabled lines, using the elevation value stored in the attribute table. With this file I exported the contours to DWG. When I import the DWG into SU the contours have Z values. I have had to scale the terrain by a value of 3.28 (SU seems to have a conversion issue from feet to metres with DWG). I hope this helps.

ryangarnett

Hi Miikka,

There isn't a defined way, but there are some work arounds. Would you want to select the points by count (ie: every 5th value in the table), or by distance? Also, are the points in a regular grid; spaced every 10 metres (for example).

Ryan

miikka1978

Hi Ryan,

It is a point grid where there is 10m space between each point. This means that 3000m x 3000m area I have 300 x 300 = 90 000 points. I think that it would be better to be able to select the point count by distance, for example 40m distance between each point. This would result: 3000m / 40m = 75 points => 75 x 75 points = 5625 points in total.

Miikka

ryangarnett

Hi Miikka,

Assuming that all your point are in order, you could do the following:

All a new column to your point attribute table as a a Whole number (ie: Temp)
Start editing on the point layer and open the Field Calculator
Check Update existing field and choose the new column you added
Type the following code into the Expression textbox: ( $rownum-1 ) % 4 +1
Click Ok
Save and stop editing.

This will give you information that will allow you to select every 4th point. In the attribute table you can type 1 in the Look for textbox and choose the new added column from the dropdown and press Search. This will give you the 4th point in the attribute table. You can save this as a new point file and you will have a thinned out point later.

miikka1978

Thanks for the tip Ryan! I actually decided to do the reducing points in Excel.

ryangarnett

No problem, glad you were able to get it done.