heightfield coordinates problem

[mt_sabao]

Hei,
Again I need your help.
So what happens is I have a DEM of a real location which I imported in terragen. I need to place accurately several models in this heightfield, but as it is very hard in terragen, i exported the heightfield to cinema4D, placed the models there, and then i was hoping to translate the coordinates from cinema to the ones in terragen.
Image A


Image B - heightfield in Cinema4D

(never mind the green area, terragen crashed while exporting, and it missed that part, but it's fine i didn't need it)

Now, what happens is although i defined in terragen the terrain size to be 300km x 220km(see image a) when i place my mouse on the upper left corner of my heightfield it doesn't read that :S So this way it makes it very confusing to translate the coordinates of my objects from cinema to terragen...
Could this possible be due to the curvature of the planet?! If so, any knows how i could do this?

thanks so much in advance
luis

[neuspadrin]

Zoomed that far out a few pixels off can easily be a few k.

Also keep in mind that theres 2 places to change the size of terrains.  The 1000x1000 right above where you place the other one is the resolution size of the image imported i believe

[Oshyan]

If you know the coordinates your objects need to be at, it's not hard to place them in TG. If your terrain is placed with the corner at 0,0 then you can just measure in meters to the point you want the objects to be and place them there by copying the coordinates from the 3D Preview and pasting them into the object coordinates. This seems easier than the export method you're using now.

As far as the accuracy goes, as neuspadrin said from this distance/altitude 1 pixel would make at least that much difference. If you zoomed in you'd get more accuracy.

- Oshyan

[mt_sabao]

thank you both for replying.

regarding the fact that being zoomed out so much i don't have much precision, i know that but still have a look at image A, the point x marks where under my mousse i read more or less 300km, 220km which were the dimensions i was hoping to read on the upper right corner...

And oshyan, i didn't understand your suggestion. Well, thing is I have technical maps (with contour lines) with the placing of my objects (future antennas of a telescope array), but no numerical values. so my plan was to project this image in terragen over the geometry and match the feature in the technical map to the mountains, buts its impossible to do,  the preview in terragen makes this impossible. so, i exported the geometry to cinema, there is super simple to do it, so this way i can know exactly know where my objects are, but now i need to know how to translate the coordinates from cinema to terragen, which would be simple in priciple if not for this issue

thanks in advance for any further help.
luis

[Oshyan]

Well, I have no idea of the C4D coordinate system, but I seem to recall there was a way to set it to measure in meters. That's assuming the scale of the imported terrain object is correct, of course. You also don't need to export the terrain from TG, you could just use the original DEM, converted into TIFF, as a displacement in C4D.

I'm really not clear on how you're placing these features in C4D that's so much easier than TG2 though. You can match up an image overlay to a heightfield in TG2 fairly easily, and my understanding is you're basing the placement of the objects on the overlay image.

I wish I could help more, I'm just having a hard time understanding what the issues here are.

- Oshyan

[mt_sabao]

Hi Oshyan,
Thanks so much for the help!

Ok, so please have a look at the image below, thats a screenshot from cinema4D (red arrows show the positions of some, it's around 60 objects). So you see, I have these two maps from the region (bigger lower res, smaller higher res) where i have the position of the telescopes. In cinema was really easy to match the images with the DEM geometry underneath, because in the viewport i was seeing what you see below, so it was just scaling and moving. Can I do this in Terragen easily? I tried and the preview takes quite some time to update, and still the image it displays doesn't provide resolution to match with the terrain. I could render, but this would take forever, and in Cinema4D it took me like 10 min to match.



Now I have the (x, y, z) coordinates in Cinema and i need to translate them to Terragen, to place the antennas in the correct spots but again, like i wrote before this would be easy task
(check image below) but from what i'm seeing in terragen, the coordinates are weird (see previous posts)...


Was this clear now?
Thanks again for any help provided.
Cheers
Luis

[mt_sabao]

Hmm, and what about Global Mapper, I don't know anything about it, anyone here used it before? Would it be of any help to me? 
Thanks for the patience guys!
Luis

[Matt]

The "size in metres" setting would only be used if you check "New heightfield", but you don't want to do that because it disables "Read from file". To control the size in metres of a heightfield that you've loaded, you need to use a Heightfield Resize operator.

What's the source of your files? May you can use georeferencing.

Matt