Is the length of the arrow indicative of the speed

[yanglq-bio]

Hi， I used this tools to analysis my 10X scRNA data,I got the loom files and combined with the seurat object,which mapped to the UMAP/TSNE dimension reduction results,now I have one questions is that the length of the arrow indicative of the speed?someone tell me it is ,but others told me it wasn’t true，Unless it’s the PCA dimension , which is linear dimensionality reduction,but in scRNA data analysis,UMAP/TSNE is usually used for dimensionality reduction.So I’m a little confused.Can you give me a definite answer?