constant Vertical Difference

durga637

Hi,
I want to know Vertical Difference = 50,100,200,312, 761 etc... of any two positions on my DEM.
Similar to vertical difference in path profile details. Here we are selecting two (start and end) points. But I want to locate any two locations(points) whose vertical difference say "V" = 10,15,26,50,150,624, etc... OR "V"greater than 126, OR "V" less than or equal to 568...etc...
Thanks,
Prasad

global_mapper

Prasad,

There isn't any way to do that automatically, I'm not sure what the output would even be. Maybe a set of 2 points and the elevation delta between them? You could of course easily do something like this yourself using the SDK, but there isn't any type of functionality like this in the application.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com

durga637

Hi Mike,
If there is no direct functionality available now, could you please guide me to achieve this?
I want to locate two areas on DEM which are satisfying "V" criteria as above.
once my first criteria "V" is satisfied, I will look for area criteria where "A" grater than 50 sq.m etc..like that.
For area, I will take help of contours and do calculations.
please suggest me any way to achieve this.
Thanks,
Prasad

global_mapper

You could setup a custom shader for the elevations with very defined colors for different elevation levels so you could visually identify the areas a particular V from a given elevation.

Another option would be to load the elevation layer twice. Use the Alter Elevations tab for the Options dialog for each layer to set one to a very small valid elevation range (alter the min/max), then do the same for the other layer but with the valid range being some V from the valid elevation range you set in the other layer. This you could see all of the elevations of a particular value and all those the V height away.

Finally you could right-click on the elevation layer in the Control Center and select to create equal value areas with an elevation fuzziness of 0.5, which should give you area features for elevation values that cover 1m each. Then you could easily select all those with an elevation some V from another elevation.

I'm still not quite sure what the real-world application of this is though.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com

durga637

Hi Mike,
I am trying your above suggestions. Yes we can do if we are very specific about height difference and this max, min elevation and equal value area options. I have streams shapefiles as well as raster files. I need to locate/highlight my streams portions on my DEM, where there is vertical height difference of 50,100,217,382 etc..... Could you please suggest me to achieve this?? I am thankful to your time and support.
Thanks,
Prasad.

global_mapper

Prasad,

Do you maybe really way to see all areas that are within some flow height of a stream? If so there is a new function in the latest v14 builds under the Analysis menu for seeing what areas flow to some other area when you raise the water level some height. So you could select your streams and create a small buffer around them, then select those buffer areas and use the new Water Rise option under the Analysis menu and create a new area showing everything that flows to the stream areas and whose flow height differential is less than some specified height delta.

I have placed a new build at http://www.globalmapper.com/global_mapper14.zip with the latest changes for you to try. Simply download that file and extract the contents into your existing v14.xx installation folder to give it a try. If you are using the 64-bit v14 version there is a new build at http://www.globalmapper.com/global_mapper14_64bit.zip .

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com

durga637

Hi Mike,
I am trying on the build provided. It is very good and useful than the existing 3DView function.And flooding analysis make this in detail. Sorry, I forgot to inform you the purpose/objective of my questions, it is to calculate energy / hydro power with constant vertical difference on DEM / Streams. I have streams shape files as well as raster files. I need to locate/highlight my streams portions on my DEM/Streams, where there is vertical height difference of 50,100,217,382 etc.....After this step, I would like to calculate energy / hydro power of the selected / highlighted DEM / Streams (may be highlighted shape files are new generated shp after the run). Could you please suggest me to achieve this?? I am thankful to your time and support.
Thanks,
Prasad.

global_mapper

Prasad,

I think the Water Rise tool is the only way you are going to reliably identify areas some fixed height away from a stream. The outer edge of the water rise area should be what is the specified height above where the flow hits the selected areas, which are supposedly from the streams. So if you used 50 meters the edge of the created area should be 50 meters above where the flow from the point on the edge of the area hits the area that you selected. I think that would make the most sense for your hydro power application.

Thanks,

Mike
Global Mapper Guru
gmsupport@bluemarblegeo.com
http://www.globalmapper.com