Can someone tell me how to use custom selection tool, example i want to have map only in red

http://imgur.com/a/uIq8A

As I understand you only want to show the part of the map which is encircled in red.
Do you have this map as SVG or as a pixelated image in Inkscape?
A simple way might be clipping:
1) use the freehand tool (F6) and draw a closed path around the area of interest
2) Select the map and the path
3) Menubar | Object | Clip | Set

See also:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Clip.html


edit:
If you want to remove everything outside the red circle (instead of just clipping it) the boolean operation "intersect" would be the right thing (Menubar | Path | Intersection). However, intersection does not work on multiple paths or groups. I am not aware whether there is a Multi-Boolean-Intersection extension. Please let me know if there is.

Multi-Division would work, too. One only needs to delete the stuff that is then a separate object. Or Multi-Difference, with an object shaped like a frame (with a hole in the middle) (the extension for it can be found here: https://github.com/Moini/inkscape-extensions-multi-bool)

Thank you guys, i will try it

What about Edit menu > Find/Replace?

First you need to find out the hexcode for the red color. Actually it looks like there may be more than one shade of red. So you would need to enter all the hexcodes for the red parts. And you'll need to set whatever other options are needed, because some of those look like strokes, and other look like fills. And even some text. So this will take some patience and maybe some trial and error. So be sure to make a backup of the file before you start - just in case. And then fnally click Find button.

Then Edit menu > Invert Selection. That will make everything except the red objects selected. And then you can just Delete.