TransDEM Forum

TransDEM News, Support, Hints and Resources
It is currently 23 Nov 2017 06:23

All times are UTC + 1 hour




Post new topic Reply to topic  [ 10 posts ] 
Author Message
 Post subject: Google Earth & TransDem
PostPosted: 31 Aug 2016 21:17 
Offline

Joined: 13 Aug 2016 03:08
Posts: 6
I have been using the tutorial "How to use Google Earth and TransDem to create routes for Trainz". My chosen area for my route(s) is quite large, approximately 100K by 136K, located in SE Texas in surrounding and including the Houston area.

I have created the image files per direction in the tutorial and am in the process of converting the jpg. images to UTM and saving the result to _georef.trf file. For the area that I have chosen, there are about 2500 +/- GE images. The saving and then incorporating these images into a master georef map is tedious to say the least.

This brings the queston to mind, "Is there a way that a sub-program(s) could be incorporated into TransDem that would do the steps outlined in the tutorial to:(1) Load the GE image, (2)Convert the image to UTM, (3)Save the UTM georef file? Also, a sub-program to capture the saved UTM georef image into the master geroref map?

Dave


Top
 Profile  
 
PostPosted: 01 Sep 2016 03:30 
Offline

Joined: 27 Aug 2016 05:00
Posts: 33
Worst case scenario, you could write a keyboard macro that could try to do that for you. Better case scenario would be if some kind of scripting could be applied to it?


Top
 Profile  
 
PostPosted: 01 Sep 2016 16:35 
Offline

Joined: 05 Jan 2011 16:45
Posts: 1057
Google Earth satellite imagery is also offered via Google Maps, at least for the most recent images. And Google Maps has a public interface which TransDEM makes use of - if you run the TransDEM Map Tile Client. You may have to adjust the settings, see here: viewtopic.php?f=7&t=451&p=2389#p2389.

With the Map Tile Client, each clipping, map or ortho-image, will be georeferenced automatically. You select the location, click Get Map and receive an image georeferenced and already converted to UTM. You also have the path option, for further automation, to acquire a series of maps/images along a given polyline.

There is a downside. Google limits access to the servers via this interface. After a few hundred clippings, they shut you out for 24 hours, based on your IP address. Then, the URL changes quite often, at least it did so in the past. And this map tile interface may be retired in the not so distant future.

This is pure speculation but there are a couple indicators which suggest this. There is, however, an official Web API, as a rudimentary REST service, which TransDEM could use instead. Unfortunately, that service is incompatible with the tile map de-facto standard. And it will require a key, which Google provides "free-of-charge", in exchange for collecting your data, of course, as they do with Google Earth.


Top
 Profile  
 
PostPosted: 01 Sep 2016 18:05 
Offline

Joined: 01 Sep 2016 00:07
Posts: 2
Edit: I deleted the content my off-topic comment. Sorry.


Last edited by OddRails on 20 Sep 2016 00:49, edited 1 time in total.

Top
 Profile  
 
PostPosted: 01 Sep 2016 19:18 
Offline

Joined: 13 Aug 2016 03:08
Posts: 6
Thank you All for your responses. Guess what I was asking about doesn't exist or cannot be programmed into TransDem from what I see. Bummer!

In my other train sim program, I can access the Google Maps program with the GE API key that they supply and display the google image over the terrain of my route area and use that image for placement of objects, rails or whatever is needed to be placed on the route to complete the scenery. What I was looking for in my post here, was a little automation of what I'm doing manually to place the imagery on the master GeoRef map.

Dave


Top
 Profile  
 
PostPosted: 01 Sep 2016 20:25 
Offline

Joined: 05 Jan 2011 16:45
Posts: 1057
davedingler wrote:
Thank you All for your responses. Guess what I was asking about doesn't exist or cannot be programmed into TransDem from what I see.
Again, it's already there. It's called Map Tile Client. Try it yourself, with the help of Tutorial 7, page 141 in the TransDEM main manual.

For Google, it does not use (as of today) the Google Maps API you are referring to from your other program. Currently it goes via the completely anonymous tile mechanism. No key needed, and no key possible. They only record your IP address. And it's the same data. But, as I said in my previous posting, they may eventually shut down this interface and we may have to go via their official key-based data-collector interface. So, use it, while it still exists.

And that's because it does exactly what you want:
davedingler wrote:
(1) Load the GE image, (2)Convert the image to UTM, (3)Save the UTM georef file?
And it even works along a path, not for a single image, but for an entire series of images (until, in the Google case, your daily ortho-image tile limit has been reached)! Which is more than
davedingler wrote:
Also, a sub-program to capture the saved UTM georef image into the master geroref map?


Top
 Profile  
 
PostPosted: 02 Sep 2016 20:10 
Offline

Joined: 13 Aug 2016 03:08
Posts: 6
OK, Got it! Thanks.

A question to those that have made use of this procedure, what is the best zoom level to use for capturing the images? Level 20 gives a fair amount of detail, but at 216 x 216 ft. I visualize several hundred images for my area.


Top
 Profile  
 
PostPosted: 03 Sep 2016 03:18 
Offline

Joined: 30 Jan 2011 13:03
Posts: 159
G'day davedingler,

As you might well imagine, the setting you use is entirely subjective and should be set according to the specific requirement of the route, as needed at the time. Having said that, I have found that level 17 usually gives me a good compromise between the level of detail, the amount of area covered and with the image size setting always at 2048, a reasonable file size with which to work. Mind you, there is nothing to stop you from combining both levels (or any other random level settings, for that matter) within the same workspace. Use the lesser setting for an overall 'look' and to give a general indication of what is where and then, in specific places, use a higher resolution to highlight locations where detail may be important (you just have to make sure that the higher detail images are 'above' the lower ones in the route's *.lgb file)...

Jerker {:)}


Top
 Profile  
 
PostPosted: 03 Sep 2016 22:56 
Offline

Joined: 13 Aug 2016 03:08
Posts: 6
Thanks Jerker, for your reply. I'm leaning toward "Hiballer's" method of adding GE images. In my system they cover an area of about 1 1/2K x 2.8K. It goes fairly fast but have to take frequent breaks because of the repetitive motions. My 83 YO arm gets to aching after about a half hour or so! LOL.

I've probably started out too large an area, but will continue on as I think it will pay off in the future. There are about 15 sets of track that run in and out of Houston, TX, USA. And within the area of Houston, primarily in the Eastern half of the city there is a multitude of oil, chemical, seaport shipping, and various other industries that use rail systems for shipments of goods, both in and out of Houston. All this along with an Amtrak service that stops in mid town and a possible "High Speed Passenger Service" between Houston & Dallas, TX in the works. So there is a lot of potential for railroading scenarios for the area.

Dave


Top
 Profile  
 
PostPosted: 05 Sep 2016 02:01 
Offline

Joined: 30 Jan 2011 13:03
Posts: 159
G'day davedingler,

Its great to see you tackling stuff like TransDEM at a 'grand' 83 years of age, Dave (and I thought I was 'old' at 20 years your junior), keep it up (we "have your back" if you need us)! Although I have created many routes on U.S. territories, I haven't yet been "commissioned" to create anything covering Houston, so I'm not entirely familiar with the area. It certainly sounds like you have your work "cut out" for you but if you take your time, it will work out in the end and you WILL be pleased the results, (geophil and I guarantee it)...

Jerker {:)}


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC + 1 hour


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
cron

Imprint

Powered by phpBB® Forum Software © phpBB Group