This document provides instructions for creating an altitude layer for Forsk Atoll using free map sources. It describes downloading SRTM data and vector maps of Ukraine from open sources. It then explains how to import and preprocess this data in Global Mapper software to crop it to the desired region and convert it to a GRID format that can be imported into Forsk Atoll for navigation planning and mapping purposes. The process is broken into steps to decrease computer load, and suggestions are provided for other useful vector data layers that could be included.

1. HOW-TO create altitude layer for Forsk Atoll by using free map sources.
Prepared by vimcma
Once I was invited to travel around the country with the off-roaders, without roads just directions. They invite me as a navigating officer. It was perfect
but the trip was not planned at all, just by starting engine and GO …
Evening before start our trip I decided to make all necessary for navigation from scratch and start digging Internet… This evening were downloaded just
SRTM and Map of Staff (100m resolution) in jpeg format. Software was trial GM version 6. As GPS receiver were taken no name made in China G-mous
(cheapest one). Stick it together and it become perfect navigation map with all villages, cities, rivers, bridges e. t. c. And as you know we are HAM radio
people and also we were taking decision where to stop and make bivouac to transmit of HF, VHF and UHF.
And during my trip were a lot of time (10 days on fresh air) to play around the mapping and results of it I want to present to you here in this short article.
On my work I’m not using Atoll just take it to vacation at one of my colleague he were without any job that time. So it was taken decision to prepare the
altitude layer from this SRTM.
So all your ideas and suggestions are most welcome!
Let’s go to se HOW-TO:

2. STEP one: PREPARATIONS
First of all you need to have couple of software packages and fast internet.
- Find topological data of the region for which you want to create the map see on picture 1 in my case it is UKRAINE.

3. - Download SRTM (zipped hgt files) for your region and load it to the Global Mapper version depend on you but now I’m using v 12.02

4. Change projection suitable for Atoll, I’m using UTM

6. Here you can se transformation

7. Next step is to define border of the region which you planning to have on the map. For this step you need to download the vector maps in SHAPE
format. It is easy to do from the site DIVA GIS (http://www.diva-gis.org/gdata) by chosing COUNTRY and which layer you need.
Also I want to writhe couple of words about vector part’s of the country on this format.
There will be available on the gdata page:
Here you can see:
- Administrative areas – here is zipped files with COUNTRY and DISTRICT areas.
- Inland water – rivers, lakes, swamps, e. t. c.
- Roads – easy to understand what is in this archive;
- all else also easy to understand what is inside;
- GAZZETER – it is the shape layer which consist points with names of town’s, cities, villages, e. t. c.

8. On the beginning we need just main country border layer Adm_0:

9. So all necessary info is imported to the tool let’s start preparation and conversion:
First of all need to select the Adm_0 layer to use this selection for cropping see this actions below:

11. The conversion is divided for this amount of steps just to decrease amount of time and load of the computer because to wait couple of day’s is not
interesting.

15. After some time you will have this beautiful SRTM layer of your map see below:

16. So now we are ready to convert SRTM to GRD (Vertical Mapper GRID format) it is suitable to be imported to the Atoll.

17. So here we are …
Best regards, and GOOD luck !!!