It's not very hard. I've made a heightmap reader once for myself...
here's how 2 do it.
step 1
Load the bitmap into your program (juzt load bitmap "Heightmap.bmp")
step 2
you need to calculate the pixels in heightmap per tile. This means if you have a 63*63 tile matrix (this gives you 64*64 adjustable points) and you have a heightmap of 256*256. Then you must read every 256/64=4 pixels to get the correct height. You can skip this part if you make just a 64*64 heightmap (i did

)
step 3
use this piece of code to scan the map and apply it to the matrix
sync on
rem load heightmap
load bitmap "Heightmap.bmp"
rem build matrix
make matrix 1,1000,1000,64,64
rem scan all pixels in the heightmap
for X=0 to 63
for Y=0 to 63
GrabColor=rgbr(point(X,Y))
set matrix height 1,x,y,GrabColor
next Y
next X
update matrix 1
do
rem ################## put some camera controls here ############
sync
loop
step 4
Build this in your application and yer done
IMPORTANT!!!!!!!!!!
it takes a while to scan the bitmap because the point command is pretty slow, and this code scans 64*64=4096 times... if you want something quicker i recommend saving and reading in a file format created by yourself or use a matrix modeling program like MagicWorld or MatEdit
Juzt a dude who likez progging