Grayscale issue: Only coastlines are rendered!

[Insane Buizel 9]

Please note I am still a beginniner trying to render grayscale to SC4, but I am having a troublesome issue:

I am trying to render a 128X96 small city map with a grayscale map that I have painted myself manually through photoshop (because I have noticed that using the Convert Isolines tool as part of the SC4 Terraformer map gets stuck on "building distance map for level XX.") 

For secret reasons, below is a sample of the entire map I am trying to render:


Whereas here is the grayscale version I have created in Photoshop :

And here is the result after waiting at least 2 hours on Simcity4:


 

What I have noticed is that the rendering starts from sea level and only rises in height slightly at the coastlines of my grayscale image. The "land" parts of my region are not accounted for at all and are just sent down to sea level. I had to click on Raise Terrain Level several times to show this result. 

Is there something I am doing wrong? Are my gray values the wrong value for below sea level and above it?
I know I have rendered the grayscale image into 8-bit, otherwise SC4 would have done nothing at all, but am I missing a step such as the resample settings before png coversion?

I am certain there may be a lot I am doing wrong but I need help figuring out any sources of this issue. This is my first map I am rendering, after all, but I am making a large map... because I can .

Can anyone help me on this?

[matias93 7,535]

That looks like a compression issue at first. Did you use JPEG images? Try with BMP.

[Insane Buizel 9]

3 minutes ago, matias93 said:

That looks like a compression issue at first. Did you use JPEG images? Try with BMP.

The original image has always been a .png and so has the exported grayscale. I never tried a BMP, but it might be worth checking out. It's gonna take SC4 a couple of hours to render as usual.

I'll post updates but in the meantime hopefully someone else can point out other potential root causes.

[Insane Buizel 9]

aaand, SC4 just instantly shut down. Nothing was lost tho.

[Cyclone Boom 16,852]

Just a thought...

To save the rendering wait times in game, it might help to use SC4Mapper to speed up the process.

If interested in pursuing this method, see the post here for details. For the issue, it might be the scale factor settings are worth adjusting from the dropdown menu before rendering. This controls how height levels are interpreted in the game, and so that could be worth experimenting around with.

[SIM-ple Jack 17,444]

I re-made your map in half the time since the OP and rendered it in Mapper. If those are supposed to be islands, you had the water set way too light. My base maps in gs are always .png. That way I can edit problems more quickly. They're also always set to sea level. Try this-

You can isolate the background(the water) in PS and raise the midtones up to .10 if you want that all to be land. Change the color to black for deep water.

[Insane Buizel 9]

3 hours ago, Cyclone Boom said:

Just a thought...

To save the rendering wait times in game, it might help to use SC4Mapper to speed up the process.

If interested in pursuing this method, see the post here for details. For the issue, it might be the scale factor settings are worth adjusting from the dropdown menu before rendering. This controls how height levels are interpreted in the game, and so that could be worth experimenting around with.

This has been helping me a lot and cutting down so much time.

All that's left is to find the right gray and the right scale factor. I might get it done and release the first iteration of the map by tomorrow.

Thank you all!

-IB