Cavechat.org

Hi all,

I thought I would start this thread 1) because my other thread on"Overlaying a Compass lineplot to ArcGIS Explorer" was getting and 2) the subject allows others who have questions about GIS software to post on here as well with out getting too far ...

Anyway, I've been able to make a KML/KMZ overlay of surveyed caves on basemaps in arcgis Editor but I have another task that I'm trying to figure out that requires a little more expertise than I have (considering I'm a beginner) so hopefully you guys can help me out with this...

Question: How can I take a 3D model (as in Cave Viewer or CaveXO(CaveX if your using anything besides vista))from a COMPASS software program and place the cave under the basemap (like in the real world)in arcgis editor and line the elevations of the cave up so I can tell how far under surface (base map) I am in any point throughout the cave?

The base map would be in 3D (display elevation)...I would think that my question would be possible to resolve if I can just find a way.... I mean really if you think about it, you have the elevations of the cave, the elevations of the base map (if a topo is available), and the shapefile, what else is there? I really believe that ArcGIS Editor could be made A LOT simpler...

I think you need DEM layers, which are free to download.

If you’re trying to see the line plot in 3D, under a topographic surface, in a way that you can rotate the model around or do a "fly by" with the camera, you have to use ArcScene. If you’re just trying to do analysis ArcEditor should answer your questions.

Have you work through the tutorials that should have been on your disks? While much of the functionality you will learn doing them may not address your needs, you will learn techniques that are quite useful. Short of taking a class, the tutorials and online training (some is free I think) are pretty necessary for learning how to use the program.

Using Google Earth is like getting on a bus. Almost anyone can figure out how to get on and off but it doesn't necessarily go where you want it too, directly. The ArcGIS programs are like getting a Ferrari and you just want it to go to the grocery store. It can do a lot more than that and you keep stalling at the stop lights. It can be frustrating figuring out how to make it "go". Work through the tutorials and you will learn how to display the data and answer the questions you have.

Surface Terrain. Here is an example showing Lechuguilla Cave with the surface terrain overlaid as It is a good example showing what can be done with ArcView using COMPASS data files.



Both the text and picture above was taken directly off of this site http://www.fountainware.com/compass/compesri.htm
For further information on this picture go to the website and have a look.

This is similar to what I would like to do with the cave i'm currently working on... only instead of the terrain that they had added I would like to have an actual aerial image of the area that the cave underlies and then have the cave lined up underneath the aerial image in 3D and have the cave lined up as it is in real life under the surface that way I can tell how far I actually am under the surface at any given point within the cave...I hope this helps explain what I want to do more throughly.

Here's the 3D Analyst tutorial for ArcGIS 9.2:

http://webhelp.esri.com/arcgisdesktop/9 ... torial.pdf

I don't know what version you have- 9.3? The process should be similar. The tutorial uses the example of Horse Cave, KY and the terrain above the cave.

You'll need the 3D Analyst extension- you can determine that by:

http://webhelp.esri.com/arcgisdesktop/9 ... _extension

"...Enabling the 3D Analyst extension: In ArcMap or ArcCatalog, click the Tools menu. Click Extensions and check 3D Analyst. Click Close. If 3D Analyst is not listed then you do not have a valid ArcGIS 3D Analyst license..."

I have version 9.3 and I also have the 3D analyst. I'm rather busy preparing for finals and other tests and I don't have the time at the moment to go through the steps but I did review the link and it definately looks like this is what I want to do with the cave im working on. Can you tilt the layers to see how far below the surface the cave actually is?

If you just want to see how far the cave is below the surface, you can do it with these steps:

1. Load the lineplot into ArcGIS

2. Use Spatial Analyst or 3D Analyst to convert the vector data to raster using the Z as the value for the cells.

3. Use simple map algebra ( [Surface] - [CaveZ]) to compute the depth of the cave for every cell where the two rasters have data.

Another option would be to:

1. Load lineplot into ArcGIS

2. Add a new column to your shapefile or feature class

3. Use the field calculator to compute the depth

4. Set the maptip to your new column and you should be able to mouse over the line plot and see the depths.


One problem with 3D vectors in GIS have two elevations. How you handle that will impact your output.

AA