Simple Hashing Function for City Coordinates

[pbialos]

Hi folks! I am working on a problem where there is a hash table involved. I have randomly distributed coordinates over a city as keys and i need a hash function to convert those coordinates to the positions of my array(hash table).I thought that maybe i could use a function to convert my coordinates to natural numbers and then using a common hash function. I am just a beginner, and my project is not very important, so most of all i need a simple solution.

Any help would be much appreciated.
Paul.

 

[ceptimus]

When you say the coordinates are random, what does that mean? Is the density of the points to be hashed greatest at the city centre, and decreasing gradually further away, or (less likely) is the density constant out to some limit, and then an abrupt stop?

The distribution makes a difference to what would be the ideal hashing function, but maybe that doesn't matter - how many coordinates do you have to deal with?

If the density varies with distance from the city centre, you might wish to convert the coordinates into polar form and then apply a linearising (inverse) function to the radius coordinate before hashing the bearing/distance pair.

 

[ravenprp]

Hello Paul,

Thank you for sharing your question with us. It sounds like you are on the right track with using a hash function to convert your coordinates into positions in your hash table. One simple solution could be to use the modulus operator to map your coordinates to a specific index in your hash table.

For example, let's say your hash table has 100 positions. You could use the modulus operator to take the sum of your coordinates (x + y) and then use the remainder when divided by 100 to determine the index in your hash table. This way, each coordinate pair would be mapped to a unique index in your hash table.

However, keep in mind that this may not be the most efficient solution for larger datasets or for more complex coordinate systems. It might be helpful to do some research on different hash functions and see if there are any that are specifically designed for coordinates.

I hope this helps and good luck with your project!