I am not skilled in web. I didn’t know that when I have in web browser opened a (scanned) topographical map it is possible to get the source of that map as a serie of squares in bitmaps. Now I know that it is possible, but still don’t know how to do it.
Those time don’t knowing it I used IrfanView program. In it you can start a process of getting meny
screenshots and they are automatically saved in files (numbered). Each time you wont the next screenshot you just press Ctrl+F11. Then I was shifting the map at a screen doing an array of overlapping screenshots. Then I have written a program to merge them in one big map. The key of merging was to find the squares of 3x3 identical pixels. The source was the scan of paper maps (1:25000) so even when all 9 pixels were forest (green) they were not the same color and in the whole map there were no next the same 9 pixels (in most cases ).
There is all kinds of specialized software for specialized applications.
In the past I have used Hugin a few times. It is a program for generating panorama’s from multiple overlapping photographs and can match with some complicated algorithms even when pictures have different lightning conditions and lens distortions etc.
If I remember well, it also has modes for stitching perfectly “flat” scanned photographs.
Where it really gets complicated though is with photogrametry. The Idea is you take a lot of pictures from some random object from a lot of different angles and the program figures out the camera positon of each photograph by itself and reconstructs a 3D object from the photographs.
It can be used with small objects such as a DMM or a cup of tea, but it has also been used with flying a helicopter through a mountain valley and photographing the whole valley.
I just didn’t thought that way. I thought if I suppose I know how to solve the problem then try to do it. If don’t know then search the program. When I needed to record sound I found Audacity (about 17 years ago). But some years later when wonted to have that map I just did it. I spend few hours on writing the working first version of those program (later was only the tune-up). I checked it also works for Google maps satellite view, but don’t works for citi plans and any painted maps - as there one color is one color so there are planty of identical small squares there.
I’m so glad!! Going to footprint and symbol category.