Messages

1

General / Re: DEM Hillshade editing

« on: May 09, 2017, 08:08:29 PM »

Hi, Thanks for that.

I know about QGIS and I usually use ArcMap for that as well.
However for what I need at the moment this would save me time. Also the resulting Hillshade from Photoscan looks a bit better than the ones from QGIS and Arcmap.

I would just need to know if it's possible to edit the min and max elevation parameters.
Anyone?

cheers

2

General / DEM Hillshade editing

« on: May 09, 2017, 06:17:19 PM »

Hi,

Is it possible to edit the scale on the Hillshade view?
Can we change the lowest and highest elevation or set classes?

Thanks
Miguel

3

General / Re: Exported Orthophoto mixes up coordinates

« on: June 26, 2015, 02:23:20 PM »

Hi Alexey,

So that means that I'll not be able to export the current view keeping the coordinate system?

The problem with the Orthophoto export is that the values also get different.
When I use the export of DEM with X,Y I get the result like on attached "printscreen of success"
But when I Export as Orthophoto and I do the same in Arcmap Instead of getting everything bellow 5m elevation in colour, I get just a few bits on the vegetation (which are higher than 5m). Please see attached "printscreen1" image.

Then I generated a raster to get everything bellow 50m elevation in red and I got what's on attached "printscreen 2".
there's nothing in the model at such high elevation, so all should be coloured. Instead I get coloured areas that are at high elevations and others at low elevations... does not make any sense.

Thanks for the prompt help!
Miguel

4

General / Exported Orthophoto mixes up coordinates

« on: June 26, 2015, 12:54:41 PM »

Hi guys,

I'm trying to export a DEM or Orthophoto into Arcmap so I can create a raster that colours everything below 5m elevation into blue (for example) simulating a flooding event.

I'm using in Arcmap: ArcToolbox --> Spatial Analysis tools --> Map Algebra --> Raster Calculator
Then, I click twice on my DEM on the layer's box to get it into the console and then I add: <= 5  and press enter. Done!
If everything works out I'll have something like in the attached image: "printscreen of success"

The issues I'm having are:

If I export the DEM in a tiff file with projections plane defined as : TopXY everything works out Ok and I can do what's described above in Arcmap.

However, if I try to export a DEM with the projection plane as "current view" (which gives me a custom view of the model) then the coordinates come all funky. Instead of the DEM having an elevation range from 0 to about 15m it shows as 0 to 250 or something crazy, and some elevations get crazy measures that make no sense.

Also:
If I export as an Orthophoto, even if I choose a projection plane defined as : TopXY the same issue happens as described above.

Here's the project's link in dropbox:

https://www.dropbox.com/s/p08wwj8yox2jsx7/Mto%20Altas%20depois%20de%20dense%20cloud.psz?dl=0


Can anyone help? Is this a bug or I'm I just doing things wrong?

Cheers
Miguel

5

General / Re: Image alignment over forested area - any tips?

« on: June 20, 2015, 05:13:54 PM »

Any updates on "removing vegetation"  in Agisoft?

6

General / Re: Approach 3D model beach

« on: June 20, 2015, 05:04:24 PM »

Hi Julien,

I'm having the same issues. I need to remove the vegetation from a beach but I'm finding it hard to do with Agisoft alone.
Did you managed to solve this?

Thanks!

7

General / Re: High accuracy without GPS

« on: February 13, 2015, 01:20:11 AM »

Hi Aggieair

That's not what I'm talking about. Forget the GPS at all.

I'm talking about using a measure tape and ground control points only.
I'm not interested in having my model georeferenced

Cheers

PS: If you are using survey grade GPS equipment (like a DGPS) and cannot get 15cm elevation, you are doing something wrong.... or you are not using "survey grade" GPS but "consumer grade" GPS.

8

General / Re: Do I need GCPs to get an accurate DEM?

« on: February 12, 2015, 01:46:39 PM »

Hi jmdg125,

You mentioned that you have the GPS coordinates from the Phantom, but that is a consumer grade GPS so the accuracy is less than 10 meters. For elevation is even worst.

So the GPS will be ok to georeference your model as a general location of your study area but definitely not a data to be used for accurate elevation measures. For that you need to use either GCPoints or a survey grade RTK with high accuracy.

What accuracy are you trying to get?

9

General / Re: High accuracy without GPS

« on: February 12, 2015, 12:48:02 PM »

Hi Whishgranter,

I'm planning on using a Sony Rx100 III and my area of interest are beaches with many features on the sand. The size is about 1km x 30meters.

I'm planning on flying at around 30meters altitude and 60º oblique angle for the photos.

From what I understand I need to have many ground control points and know the distance between them etc for the model to calculate elevation with enough accuracy. Is this correct?

Thanks for your help
Miguel

10

General / High accuracy without GPS

« on: February 11, 2015, 06:07:13 PM »

Hi,

Anyone knows if it's possible to get a terrain model with high elevation accuracy (around 15 centimetres/ 6 inches) without using a GPS? I don't need to locate the model geographically, just the elevation within the terrain.

I was told that If I use several GCP's  spread along the terrain and know the exact measure between them and their elevation difference between them, I can get a very good accuracy.

Anyone tried something similar or has any better idea to achieve this?

Thanks for your help
Miguel

11

General / Re: GoPro with modified lens for high accuracy DEM

« on: February 09, 2015, 06:30:11 PM »

Hi CS,

Thanks for your reply!

So If I set a few GCP's and I know their exact measures between them, could that work as a way to get a greater accuracy?

I'll look into the GoPro once more then... thanks!

12

General / Re: GoPro with modified lens for high accuracy DEM

« on: February 06, 2015, 03:27:01 PM »

Hi Cs,

For the GCpoints I'm thinking of setting a few 1m sticks vertically on the sand across the beach and use them as gcp since I know their exact height. Would you think this would work?

Is there another way of getting an accurate elevation without using any expensive survey equipment like a Differential GPS?

About the GoPro, from what I read here on the forum, the issue is not only the lens "defishing" but the rolling shutter...

13

General / GoPro with modified lens for high accuracy DEM

« on: February 05, 2015, 05:08:27 PM »

Hi,

For my project I need to "see" the elevation of a beach to an accuracy of 10cms or less.
Since I don't have much money for this, I was thinking about buying the Phantom 2 and GoPro with Gimbal, PFV and pre set flight patern since this is a cheap all in one setup.

Then I saw that the GoPro is an issue because of the too wide angle lens and the rolling shutter, so I tried to find another solution until I saw this tread by Porly:
http://www.agisoft.com/forum/index.php?topic=2480.0

He says that with a modified lens to 60ª he saw no difference from a professional setup, except the quality of the orthophoto, but that the cloud point was no different.

Anyone has good experiences with a modified GOPro for accurate height calculations?

Cheers

14

General / Re: Using a GoPro & Photoscan

« on: February 05, 2015, 02:41:48 PM »

"If you're using a GoPro on a Phantom, which seems pretty common these days, keep in mind that you can mount mirrorless dslrs on them too, and get much better results."

MortarArt, I which I could do that, but where do you get a Gimbal for those cameras that fits the Phantom? Even if you find a universal Gimbal it would be a fixed one right? no in flight adjustments...

15

General / How to mount an external camera on a Phantom 2 ?

« on: January 22, 2015, 03:32:42 PM »

Hi,

I'm thinking of buying the Phantom 2 and use a compact camera since the Gopro or the built in cameras from DJI have all too wide angles and rolling shutters.
I pretend to take advantage of the DJI phantom 2 capability to have pre set up flight paths.

Problem is I can't find any gibles for other cameras besides the GoPro. All gibles models on the DJI website are for the GoPro or for older DJI copter models.
How are you guys doing it to use the phantom 2 and other cameras besides the GoPro?

Is there any other cheap equipment combination beside this one?

Are you using a live view of the flight  as well? is this important?
I'm planning to take photos at about 30 meters high as I need a good elevation resolution around 10cm accuracy.

Thanks!