You've got a cool desert here, brah but I believe that there are two minor issues that could be dealt with before it is truly finished.
You've generally given the play a good degree of space to move through the map which is really good - Not confining them definitely helps to give the feeling of a large and expansive desert. However, there is a rock formation literally in the centre of the map which forces the player to walk down a one-tile path no matter which way they try to bypass it. Also, when the player exits the cave in the top right of the map they will find themselves standing on sand which houses wild Pokemon. Personally I don't think immediately throwing them into the sand is a good idea so I'd suggest giving the player 2-3 tiles of regular ground before having them face wild Pokemon. As a whole though, your sand placement and mountain formations are very good
FIX THOSE DARN TREE ERRORS
The constant use of zig-zagging paths doesn't really appeal to me in this map. The manner in which you have constructed them is such that they only go straight for three or four tiles, before going diagonally for an equal or greater length. To me, paths are man made and should be walked on, meaning that they go straight rather than bending every two or three steps. You could make the paths less diagonal and more linear by rearranging the position of your buildings so that the two houses are on the same Y Axis (So you don't have to reposition the path a space higher once you near the right house, while the path down from the lab could cut right in between them (rather than drifting in from the left).
That big bush next to the left house looks very nice so you could perhaps find another spot to place those tiles - Maybe to the right of the lab since there doesn't seem to be much there apart from a sign.
First up: You're going to have border errors because the mountains are still within view when the player reaches the edge of the map. Simple fix n shizz.
I think that the area around the four trees in the middle could have been better used than having a path circle its way around it. Perhaps you could leave the path (and trainers) on one side and have the other half covered with tall grass. It makes the map a bit more interesting and helps to put some more grass on the map because like hinkage said, it needs some more.
It seems my map was ignored. Mind if I repost this? Kay, thanks.
This is an interesting idea for a map - I haven't seen too many heavily industrialised cities/ towns. While it might have a cool idea, there are a few issues that prevent it from becoming as good as it should be.
Your square paths in the bottom and right of the map really fit in well with their surroundings so I must commend you on that, but once the player climbs the stairs to visit the Gym or Mart your method of mapping paths falls to the wayside. Rather than presenting the player with a clear cut line you have it consume everything, which doesn't look very good in my opinion. I'd suggest that you cut down on the way you are using the ground in the top of the map (e.g. only make a short 2-3 three tile long pathway to the gym from the stairs) or remove it altogether from the area.
You have a number of one-tile paths around your major buildings which easily restrict the player's movement and should never be in any map generally. The path to the left of the Gym and both in front and above the Mart are prime examples of this and should be avoided. Unfortunately you're going to have to re-arrange you buildings accordingly to correct this in the map, but from the player's perspective it will be so much easier and enjoyable to walk through your city.
I know your city is suppossed to be heavily industrialised, hence the lack of large trees and flowers, but adding some of these tiles can help to vary up the landscape by breaking up the grass, path and mountain domination of this map. I'm not saying to put in a heap of these tiles, but one or two large trees and a handful of flowers wouldn't hurt this city in the slightest, particularly since you're already using small trees around the power station. On a somewhat unrelated note, you're technically using the wrong tile for some of the corners of your mountains. Use blocks BA and BB on the standard FR/LG tileset rather than the top edge of the mountain (You've been using block 6C).
Your map is also going to experience a number of border errors stemming from your use of mountains around the edges. For example, there is a portion of rock jutting out from the border just below the Pokeball on the left hand side of this map. If you were to travel to this are in-game you would be able to see that the mountain will suddenly dissolve into nothing. You will have to remap this segment of mountain in your map, or extend the edge of map beyond the player's view so they can't see the resulting tile error. Unfortunately you're going to find quite a few errors of this kind in the map so resizing and remapping large section of the city seems like it will be the only way to fully correct this. On a somewhat smaller note, the player is technically able to avoid using the gatehouse on the right hand side of the map because the top row of it's roof should be passable - You're going to have to extend it's roof one tile upwards to avoid this confusion.
Well, that was quite a long review. I really like your idea for this city, but your mapping still needs some improvement since these errors I have mentioned stack up and may have to result in a large remapping if you want to make everything perfect. Don't worry though, just keep on practising and study both the original Gamefreak maps (since it appears to be your style) as well as those made by other hackers to get an idea of how everything should fit together :)