Survey of Geospatial uses in SketchUp
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can qgis export a point cloud? There are ruby plugins to help turn point clouds into TINs.
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Chris it depends on what you mean about a point cloud. QGIS can save a file that has thousands to millions of points (like LiDAR) but the big part is the file format. Most spatial vector data is stored as a Shapefile or as a database layer, this is something that is not handled by SU. miikka1978 I have had the same issues with QGIS and storing 3D data. I put out a post on a forum a while ago about this ( http://gis.stackexchange.com/questions/27937/features-to-3d-from-2d-in-qgis ), but I have never been about this make it work successfully. I have had to result to using ArcGIS, but when I import my contours as DWG, they are scaled wrong, by a factor of 3.28, which is the conversion from feet to meters.
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Wrong scale is an irritation yes, but it shouldn't be a roadblock. Just rescale the things.
qgis can't export a the database as a series of text xyz coordinates?
12.1,221.22, 0.112
31.321,123.12,312.23something like that? If you have that, its fairly easy to get it into SketchUp.
I'm not familiar with qgis. Sounds neat to have open source gis, but it also sounds like it needs to beef up its exporter capabilities so it can work with other software?
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Hi Chris,
Yes I have rescaled it, pain, but not a show stopper. QGIS can export to an xyz file. I have to say that QGIS is beefy and there are many many many different output formats. QGIS has a great development community, and an excellent user forum (like this one). There is very little I cannot do in QGIS that I can do in ArcGIS. Its worth a try, and if you need some assistance along the way, let me now.
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I'm just trying to help miikka on this one. They said they couldn't get contours out of it, so I suggested exporting to a xyz pointcloud text file. SU has plugins that can handle that I think.
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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.
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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
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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,
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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.
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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. -
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
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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
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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.
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Thanks for the tip Ryan! I actually decided to do the reducing points in Excel.
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No problem, glad you were able to get it done.
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