That's a short program (140 lines) that allow you to draw the height of matrices... You cannot do another thing, but you can do it easily and fast.

How does it works ? First, draw your heightmap with boxes (click on the greye box on the left to choose the color). To draw the boxes, click in the red square and let the mouse down. Move the cursor and release the mouse button... Easy, isn't it ?
When you've drawn the map, click on "Export".. Answer the questions, wait until the image is blured enough and save.
Then, the matrix will be loaded so you can see how it looks like - and you have the code to load it.

Now works with lattest patch :)

                                    ` This code was downloaded from The Game Creators
                                    ` It is reproduced here with full permission
                                    ` http://www.thegamecreators.com
                                    
                                    
 set display mode 400,300,32
sync on
sync rate 0
set text font "fixedsys"
set text size 20

dim boxes(1000,5)
color = rgb(128,128,128)
do
	cls
	gosub draw
	if mouseclick()=1 and mousex()>9 and mousex()<41 and mousey()>21 and mousey()<277
		color = point(mousex(),mousey())
	endif
	
	if mouseclick()=1 and mousex()>99 and mousex()<301 and mousey()>49 and mousey()<251
		rem get image 
		startx = mousex()
		starty = mousey()
		inc b
		repeat
			cls
			gosub draw
			ink color,0
			box minimum(startx,mousex()),minimum(starty,mousey()),maximum(startx,mousex()),maximum(starty,mousey())
			sync
		until mouseclick()=0
		boxes(b,1)=lim(startx,100,300)
		boxes(b,2)=lim(starty,50,250)
		boxes(b,3)=lim(mousex(),100,300)
		boxes(b,4)=lim(mousey(),50,250)
		boxes(b,5)=color
	endif
	
	if mouseclick()=1 and mousex()>168 and mousex()<232 and mousey()>173 and mousey()<297
		goto export
	endif
	sync
loop
draw:
	ink rgb(255,0,0),0
	line 99,49,301,49
	line 301,49,301,251
	line 301,251,99,251
	line 99,251,99,51
	line 9,21,41,21
	line 41,22,41,277
	line 41,277,9,277
	line 9,277,9,21
	for t=1 to b
		ink boxes(t,5),0
		box minimum(boxes(t,1),boxes(t,3)),minimum(boxes(t,2),boxes(t,4)),maximum(boxes(t,1),boxes(t,3)),maximum(boxes(t,2),boxes(t,4))
	next t
	box 10,22,40,277,rgb(0,0,0),rgb(255,255,255),rgb(0,0,0),rgb(255,255,255)
	
	ink color,0
	box 325,125,375,175
	ink rgb(255,255,255),0
	center text 350,180,str$(rgbr(color))
	rem 60*20, centré sur 200,275
	line 168,273,232,273
	line 232,273,232,297
	line 232,297,168,297
	line 168,297,168,273
	center text 200,275,"Export"
return

function minimum(a as float, b as float)
	if a < b then exitfunction a else exitfunction b
endfunction b

function maximum(a as float, b as float)
	if a > b then exitfunction a else exitfunction b
endfunction b

function lim(x as float,y as float,z as float)
	if x < y then x = y
	if x > z then x = z
endfunction x

export:
CLS
set cursor 0,0
print "Drawing a bitmap..."
create bitmap 1,200,200
	for t=1 to b
			ink boxes(t,5),0
			box minimum(boxes(t,1)-100,boxes(t,3)-100),minimum(boxes(t,2)-50,boxes(t,4)-50),maximum(boxes(t,1)-100,boxes(t,3)-100),maximum(boxes(t,2)-50,boxes(t,4)-50)
	next t
	ink rgb(255,255,255),0
set current bitmap 0
print "Done."
input "Tiles on X axis> ",tilesx
input "Tiles on Z axis> ",tilesz
print "Thank you."
print "Now, we need to blur the bitmap."
print "When you think it has been enough"
print "blured, press returnkey."
print "When you're ready, press any key."
repeat
	sync
until scancode()>0 and returnkey()=0
clear entry buffer
repeat
	cls
	blur bitmap 1,5
	set current bitmap 1
	get image 1,0,0,200,200
	set current bitmap 0
	paste image 1,100,50
	sync
until asc(right$(entry$(),1))=13

cls
name as string
print "It is done. The matrix is written."
print "Write the name of the file where"
print "you want to save the matrix"
input ">",name
if file exist(name)=1 then delete file name
print "Building the map ..."
sync

set current bitmap 1
open to write 1,name
	write file 1,tilesx
	write file 1,tilesz
	
	for x=1 to 200 step (200/tilesx)
		for z=1 to 200 step (200/tilesz)
			write file 1,rgbr(point(x,z))
		next z
	next x
	set current bitmap 0
close file 1


REM X-X-X-X-X-X-X-X-X-X-X
REM HERE BEGINS THE CODE TO
REM OPEN A MATRIX

open to read 1,name

read file 1,tx
read file 1,tz

make matrix 1,1000,1000,tx,tz
for x=1 to tx
	for z=1 to tz
		read file 1,h
		set matrix height 1,x,z,h
	next z
next x

update matrix 1
debug = mousemovex()-mousemovey()

do	
	xrotate camera wrapvalue(camera angle x()+mousemovey())
	yrotate camera wrapvalue(camera angle y()+mousemovex())
	move camera upkey()-downkey()
	sync
loop