# Best Content of All Time

• ### Digitize Line in Profile View

Hello: I quite agree with this need. A manual ground profile estimation by means of this human guided interpolation would be great. I'm right now facing the very same case and it is taking ages to select points and assign ground class, while it would be a lot faster and simpler to draw a low-pass line...
• ### Error setting 3D viewer info

Hello,

First, I suggest updating to the latest version of Global Mapper 17 so you can see if this is a problem that has already been fixed.  If the problem persists, you should contact Blue Marble Geographics Support directly via e-mail (geohelp@bluemarblegeo.com).

Cheers,
Bob

• ### tools for calculating volume

curves said:
I have been experimenting with certain tools to calculate the volume of water in potential dam sites. I have been using the 'pile volume' tool which gives an array of feature information including varied data on volume. when I calculate the volumes using mathematical formula I get a very different answer than that given by the pile volume data.
Is this tool accurate and reliable for this type of calculation? Is anyone using this tool for the same purpose? Can anyone shed some light on why there is so much variation in calculation methods?

Many Thanks
Bruce Kirk
I'm not sure what "mathematical formula" you used for confirmation but before I started using GIS extensively, the normal method was to use your contour map to compute the area and the elevation of the contours within the reservoir area, then apply the conic or end-area method to compute the volume between the contours and cumulate for the entire reservoir. Usually we ended up with a plot of the Height-Area-Capacity curve to show the characteristics of each potential site.

My current work flow using Global Mapper involves:

1: Generating the contour map using the DEM and creating an area feature of the reservoir at the desired contour elevation.

2: Select the area feature and initiate the volume command

3: Choose the "Perform multiple calculations over a range of base heights" and enter the lowest and highest elevations within the area (425 to 440 as shown), then press "OK".

4: The results are shown below with the highest "fill volume" highlighted as 13,285,150m3.

5: You can copy to clipboard and paste to MS Excel to generate graphs live below.

6: If you want to have a more direct volume computation, just do step 1 - 2 and choose "Use same base height value for all vertices", enter the desired elevation (440 here) and ensure the value is selected as "above sea level".

7: Voila, the fill volume is same.

I have verified this with the manual method and the volumes are not significantly off.
• ### Hexagon Grid?

Hello DerrickW,

Done. Thank you for your interest.

Cheers,
Bob
• ### Create a pond from lidar data holes.

That's a very good question which had me thinking. I too have lidar data with holes. My back of an envelope solution is to go Options, Alter Elevation Values and clamp the invalid data to a value egregiously outwith the terrain elvation. The invalid areas should now show in a striking colour, assuming your lidar grid is shaded.

I then created contours at an appropriate level (e.g. 1m). You can now copy the contours that appear around the "holes" using the Digitiser tool, move them to a new layer and then convert them to polygons. There is doubtless an easier way but I do not know it.

• ### How can load las data and treat elevation as depht using sripting langauge?

Hi DANBRI,

It looks like your parameter is not spelled correctly. It should be: IMPORT FILENAME="......" ALT_MODE="DEPTH". Give that a try and report back if it doesn't work.

Best regards,

~Jeff
• ### Google Map Tiles Data Source - File Names Too Long

“Long Path Tool” is very helpful for this error !