Convert transcript position to genomic position

Question

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Hi, I'm a newbie in bioinformatics, maybe this question was already answered somewhere else. I'm working on tobacco samples and I've already predicted miRNA cleavage positions to a reference transcriptome. Now, I want to convert these transcript positions to genomic positions. So for example:

On gene X, I have a predicted cleavage position at 1539nt from the first base of the 5'UTR. This position on the corresponding scaffold is 2369875.

Is there any easy-to-use tool which can use gff/gtf file to "map" these coordinates?

Any help will be very useful!

Thank you,

Andrew