Export raster data

[Rasmus Pierong]

Hi!

 

I'm working with storm event analysis in HEC-RAS. At the moment I'm engaged in a city development project where I need to get information about the planned surface elevation within the project from an other consultant that uses the program Vectorworks. The problem here is that HEC-RAS is raster based wheres Vectorworks seems to be vector based. I need a .tif file for import to HEC-RAS. I could work with other formats then .tif as well as long as it is some kind of DEM model or even point cloud that I can convert to .tif. So my question is - con you recommend how to export the surface from Vectorworks in order to facilitate the conversion to .tif?

 

Kind regards

Rasmus Pierong 

[line-weight]

A while ago I wondered if this was possible in the other direction (import file with elevation data in raster format and convert to something vector based) and I think the answer is no. I'm by no means an expert in this stuff but you probably need to do the conversion in another application. If it *is* possible I'd be interested to know how.

[BartHays]

This sounds like a @Jeff Prince question. 

My limited knowledge of terrain models makes me wonder if the VW user could set up the terrain model to show "3D Grid (Elevation)" and reset the Graphic Properties to go from Black to White. When viewed in plan in a shaded render mode you get a "depth map" type of look. You might be getting somewhere.

However, It might be too cumbersome to set the grid size to something useful for data analysis. 

 

[Jeff Prince]

@Rasmus Pierong You are likely going to need to take a stop in ARCGIS to do data translation.  If the Vectorworks drawing is geolocated, it can be exported to DWG and then imported into ARCGIS.  There, you can take the contours and produce a DEM or Shape File that HEC-RAS should be able to ingest.  Alternatively, a translation could be done from Autodesk products like Civil 3D or AutoCAD to get the information in a Shape File.

 

Just be very careful, Vectorworks operators vary in their skill levels and geolocation in particular seems to cause people a lot of grief.  The challenge is compounded when needing to translate data that Vectorworks hasn't adopted as native export formats... this requires you to check the data at ever step to make sure it is translating correctly.

Good luck, report back when ends up happening and if you are successful.

 

35 minutes ago, BartHays said:

This sounds like a @Jeff Prince question. 

My limited knowledge of terrain models makes me wonder if the VW user could set up the terrain model to show "3D Grid (Elevation)" and reset the Graphic Properties to go from Black to White. When viewed in plan in a shaded render mode you get a "depth map" type of look. You might be getting somewhere.

However, It might be too cumbersome to set the grid size to something useful for data analysis. 

 

You could produce a DEM like elevation model like this.  Unfortunately, the way Vectorworks applies the colors is not fine enough to produce smooth transitions with meaningful data values.

 

Attached is an informational poster I made 20 years ago about making landscape visualizations from DEMs.  I wish Vectorworks could import them like Rhino and so many other softwares can.GPH370-final-prince.pdf

[Rasmus Pierong]

Thank you very much for your input. We will most likely proceed with the alternative to export contours from VW and in GIS software convert them to DEM. Some more work in VW is required before we will do this but I'll get back to you when it is done 😃

 

One more question. There is a mesh export alternative in VW, may this be a good alternative to contours?

 

//Rasmus

[Jeff Prince]

7 hours ago, Rasmus Pierong said:

One more question. There is a mesh export alternative in VW, may this be a good alternative to contours?

if you take your site model displayed as a Mesh and Ungroup it while in a 3D view, a mesh is one of the things produced.  If your model is displaying extruded contours, that’s what you will get during an ungroup.

 

Similarly, if you ungroup in 2D, you will get all of the 2D objects created to portray the site.

[line-weight]

@Jeff Prince a sort-of related question.

 

I want to use the data that's freely available here:

 

https://osdatahub.os.uk/downloads/open/Terrain50

 

and produce a kind of shaded terrain map. It doesn't necessarily have to be in 3d, because I will only show it as a top-down map image.

 

I want to create a map that only shows the terrain topography. It doesn't need to show anything like roads etc. The purpose of it is to visually convey the land elevation, and primarily to highlight where steep terrain is.

 

I started out thinking that I could try and import the data to VW in such a way that I have a 3d terrain model, then simply try lighting it from the side to try and get the effect that I want. That's because I am familiar with VW but not really with GIS applications. I have messed a little bit with QGIS so far.

 

Is trying to bring it into VW wrong-headed? Should I just be trying to do it all within QGIS instead?

[Jeff Prince]

2 hours ago, line-weight said:

@Jeff Prince a sort-of related question.

 

I want to use the data that's freely available here:

 

https://osdatahub.os.uk/downloads/open/Terrain50

 

and produce a kind of shaded terrain map. It doesn't necessarily have to be in 3d, because I will only show it as a top-down map image.

 

I want to create a map that only shows the terrain topography. It doesn't need to show anything like roads etc. The purpose of it is to visually convey the land elevation, and primarily to highlight where steep terrain is.

 

I started out thinking that I could try and import the data to VW in such a way that I have a 3d terrain model, then simply try lighting it from the side to try and get the effect that I want. That's because I am familiar with VW but not really with GIS applications. I have messed a little bit with QGIS so far.

 

Is trying to bring it into VW wrong-headed? Should I just be trying to do it all within QGIS instead?

 

 If you do a lot of map or GIS work and have the patience to learn QGIS, it would be a good skill to have.  I dabble in QGIS and Blender, so each time I need to do something, I have to look up the specifics of what I need to do.  Both programs have nuanced interfaces that require you to know a bit about the data you want to work with.

 

So, for your project, I would download "ASCII Grid and GML (Grid)". This data is basically all of the UK as height field data.  That's greyscale data where the more white something is, the higher in elevation, like a bump map but indexed to real world elevation.  A lot of files and folder will be downloaded, but they are organized by the UK national grid, so that makes it easier to find your project area at least.  I decided to look at the town of Dover since I know there is some topographical relief with the cliffs and such.

 

The data from the GML package can be displayed in several ways.

The left image is displaying two modes Hillshade (upper left corner) and Contours at intervals of your choosing (rest of image).

You can also show it in the native height field as shown in the right image.

 

From this point, you could continue working in QGIS and develop a pretty nice shaded relief map with aerial photography or other enhancements.

Alternatively, you can export the height field from QGIS to TerraGen and do some amazing visualizations from what I have seen.

You can even export this information to Vectorworks as OBJ (recommended) or contours (not recommended) where you can use familiar tools to color and enhance the map.  The only problem with going into Vectorworks is you have to orientate the OBJs as they are brought in (rotate in 3D and move next to adjacent tile).  Now would be a good time to "add geolocated heightfield import" to the Wishlist since pretty much every other software we use can import this commonly available data and display it in 3D.

 

Even though QGIS is cryptic and not very forgiving of user errors, there are a ton of videos that can help you figure out just about any task.

 

 

 

 

 

Edited September 24 by Jeff Prince

[line-weight]

18 minutes ago, Jeff Prince said:

 If you do a lot of map or GIS work

Not really!

 

So a way of doing stuff in VW, even if it's more clunky, might be more efficient for me, rather than trying to figure out the finer points of QGIS.

 

If I import to VW as OBJ what do I actually get - a kind of mesh?

[Jeff Prince]

7 minutes ago, line-weight said:

If I import to VW as OBJ what do I actually get - a kind of mesh?

 

Yes, you get a typical OBJ mesh and if you textured it in QGIS, that comes along for the ride too.

[line-weight]

10 minutes ago, Jeff Prince said:

 

Yes, you get a typical OBJ mesh and if you textured it in QGIS, that comes along for the ride too.

 

Ok. Thanks.

 

If I wanted to make a VW site model object (to then fiddle around with the various 2d visualisation options it offers) I guess I'd have to import as contours and then make them site model source data?

[Jeff Prince]

11 minutes ago, line-weight said:

 

Ok. Thanks.

 

If I wanted to make a VW site model object (to then fiddle around with the various 2d visualisation options it offers) I guess I'd have to import as contours and then make them site model source data?

 

You can convert an OBJ to 3D polys and then use those to make a site model.

Alternatively, you could place loci on the surface of the OBJ and use those to make the site model.  There are a few "macros" floating around the forum for placing Loci that way.  This is probably the better option because you can control the density of points to suit your needs where OBJ ->3D Poly can be a bit heavy.

[line-weight]

@Jeff Prince thanks for the pointers you gave me above.

 

Once I started fiddling a bit with QGIS I got drawn in, and ended up producing much of the mapping imagery I wanted in there, instead of trying to import something 3d into Vectorworks.

 

It took me a little while to understand how things work, but it's kind of addictive once you get into it, especially with all the freely available mapping data that can be used. Here's what I've produced so far, which is a representation of the terrain underlying south London. I would not have been able to do this inside VW.

 

 

 

[Tom W.]

37 minutes ago, line-weight said:

@Jeff Prince thanks for the pointers you gave me above.

 

Once I started fiddling a bit with QGIS I got drawn in, and ended up producing much of the mapping imagery I wanted in there, instead of trying to import something 3d into Vectorworks.

 

It took me a little while to understand how things work, but it's kind of addictive once you get into it, especially with all the freely available mapping data that can be used. Here's what I've produced so far, which is a representation of the terrain underlying south London. I would not have been able to do this inside VW.

 

 

 

 

I'm interested to know how you will use this in your project + what kind of project it is...?

[line-weight]

1 hour ago, Tom W. said:

 

I'm interested to know how you will use this in your project + what kind of project it is...?

 

This is a non-architectural project... a personal interest one that involves mapping & explaining the development of the railways of south London. A bit niche!

[Rasmus Pierong]

It worked well with contour lines, thanks for input Jeff Prince!

 

Kind regards

Rasmus

[Jeff Prince]

On 10/1/2024 at 1:36 AM, line-weight said:

@Jeff Prince thanks for the pointers you gave me above.

 

Once I started fiddling a bit with QGIS I got drawn in, and ended up producing much of the mapping imagery I wanted in there, instead of trying to import something 3d into Vectorworks.

 

It took me a little while to understand how things work, but it's kind of addictive once you get into it, especially with all the freely available mapping data that can be used. Here's what I've produced so far, which is a representation of the terrain underlying south London. I would not have been able to do this inside VW.

 

 

 

Very nice!   I love maps with topographical relief.  I’m glad you were able to interact with QGIS.