ACWCO Engineering Department


ACWCO Engineering Dept.


Creating HPS/JTS ACW Game Maps with East Front


Beginning with Corinth 1.02 the HPS ACW games had the .map files locked out so that only the original files would work within a particular game engine. You could make your own MAP file and load it into the Scenario Editor, it would work fine there and you could create a scenario file with it. However when you attempted to start the scenario file in the game engine you would get an error message.
However with the release of the JTS game Overland the .map files appear to have been opened up again. Currently those HPS/JTS games that have been updated to version 2.0 or later allow maps other than the originals to be loaded.


Making map files with Talonsoft's East Front Map Editor

Checksum Generator programs


Creating HPS ACW Game Maps with
Talonsoft's East Front Map Editor

First you should be aware of the fact that because it was designed for a tactical game the East Front Map Editor has some limitations that will affect your map making, the biggest one being the maximum number of elevation levels it supports is 13 while some of the newer HPS engines currently use maps with over 20 elevation levels.

In order to create your own maps you will need.

  1. A copy of Talonsoft's East Front Game which includes a map editor.
  2. A text editor with a Replace function for modifying the map file text to convert it from East Front to HPS ACW format.
  3. A Checksum calculator program, two are available for download on this site.

Before going any further I wanted to mention that these instructions are for the original East Front Map Editor. I managed to get hold of a copy of East Front II and looked it over but it appears some type of encrytion was put in this second version. This causes the characters in the map file to vary from one map to another making it difficult if not impossible to use this version of the Map Editor for creating ACW maps.

Since there are some differences in the format of East Front and HPS ACW maps you need to follow some guidelines when using the East Front Map Editor. Below you will find a table listing the comparable terrain used by both games, as you can see although many of the letters are the same there are a few differences in the letters used for the base terrain and the position of the blocks for some of the hexside terrain features. Also East Front has additional terrain features that have no comparable HPS ACW feature and these have been left out of this table. A more complete Excel version of this table is available for download on this page.

EF Terrain Letter HPS Terrain Letter
Clear space Clear space
Water w Water w
Forest f Forest f
Swamp s Marsh s
Village v Town t
Orchard o Orchard o
Rough r Rough r
Field e Field d
Blocked x Blocked x

EF Hexsides Block HPS Hexside Block
Path 17 Trail 3
Unpaved Road 14 Road 4
Paved Road 3 Pike 5
Railroad 4 Railroad 6
Stream 5 Stream 7
River 6 Creek/River 8
Hedge 10 Fence 9
Cliff 12 Stone Wall 10
Embankment 13 Embankment 11
Gully 15 RR Cut 12

I recommended using the designated East Front terrain for a particular ACW terrain type. This is not the only way to do this but it is the way I have used, I think it is the easiest way and it works. A step by step procedure follows. I recommend you start with a small test map and do this a couple times to get the hang of it before attempting anything large.

Using the tables above create your map using the recommended East Front terrain types. Due to differences in the way the two games handle the map files you will need to make several changes to the .map file using your text editor. I suggest after completing your map you copy and save your map under a new name, say you called it, then use as the new name. This will allow you to have the original East Front map and your modified HPS map. This will make it easier to affect the changes needed and keeps your original safe in case you mess up the modifications.
In addition to the differences in the letters used for some terrain features the map files for the two games are built a little differently. As noted in the Map Files Explained section of this site the HPS ACW maps are divided into a Header section, a Terrain block, an Elevation block, 10 Hexside Terrain blocks and a Labels block. East Front also has a Header section, a Terrain block, an Elevation block, but it has 15 Hexside Terrain blocks, an additional block who's function I do not know and a Labels block. Several of these blocks are not needed for the HPS ACW games and in fact will cause problems if you attempt to load an East Front map into a HPS engine.
The first change you need to make will be to replace the East Front Village letter v with a t. This can be easily done using the Replace function. You want to use the Replace Next function not the Replace All as this may mess up any Label names you have put in the map. You only want to replace the v's in the first block of the map file as described above.
Next you want to do the same thing replacing the East Front e for Fields with the HPS d.
The elevation blocks are the same in both maps, a series of numbers from 0-9 then letters from a-c desginating the elevation level of each hex from 0-12, so you do not need to make any changes in the second block.
The next set of blocks contain the biggest differences between the two types of maps. As noted above the HPS ACW game maps have 10 Hexside Terrain blocks while the East Front map has 15. If you used the suggested East Front Hexside Terrain features you will have 5 unused East Front blocks that will consist only of a 0, an indication that block is not used. However you will still need to move the East Front blocks into the correct positions in order to get them to work properly in the ACW engine.
A good way to do this would be to start at Block 3, in the line below the end of the Elevation Block. There you'll see a line containing either a 0 or a 1 depending on whether or not you had any Paved Roads (ACW Trail) hexsides in your map. If a 1 it indicates the start of block 3, if a 0 it would indicate there were no Paved Roads used in your map. I suggest you replace the 1 with a 3 then scroll down through the file replacing the 1 or 0 at the start of each block with the next number in the sequence. When done you should have 15 lines containing a single number from 3-17 with a series of blocks of various characters between them.
Blocks 7-8-9-11-16 should consist of single lines since if you followed the instructions you should not have used these blocks so you can highlight those lines and delete them.
Just below the end of block 17 you should see a 1 followed by something similar to the Terrain and Elevation blocks. I'm not sure what the function of this Block 18 is but it is not needed for the HPS ACW engine and can also be deleted. You are now ready to move the blocks into the correct order.
If you look again at the table above you'll see the correct order to place the East Front blocks in order for them to match the blocks in the HPS ACW engine. You'll note that several of the blocks, 3 through 13 will not need to be moved if you move the others into the correct positions and delete the unused blocks as noted above.
Now you want to highlight block 14, using the Cut feature, cut it out then paste it in front of the 3 designating block 3. Then do the same thing with block 17 pasting it in front of block 14. If you have already deleted blocks 7-8-9-11-16-18 then you should now have a map file consisting of a Header section, a Terrain block, an Elevation block, 10 Hexside Terrain blocks in order 14-17-3-4-5-6-10-12-13-15 and a Labels block.
The only thing remaining to be done is to replace the numbers you put in earlier with a 1 if that block was used and a 0 if it wasn't. After doing that you can save your map file and you are ready to determine the Checksum for the file.

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Leib Checksum Generator Program


The old Leib Utilities included a DOS based Checksum Generator. I have made that program available

This program has several limitations, the biggest one being it will not handle large maps. If your map is too large you will get an error message. Also I have not checked the operation of this program beyond Windows XP, I have no idea if it will even run in Win 7 or above.

As noted above this is a DOS program and will have to be run in a Command Prompt window. In order to use this utility you will have to follow use the following procedure.

  1. Copy the .map file into the folder where you extracted the Lieb utilities, rename it to, this is the only file name the acwcksum.exe program will work with. Make sure you have the file acwcksum.exe in the folder.
  2. Go to Start, Accessories, Command Prompt to open a DOS prompt window. Use the Change Directory Command (CD) to navigate to the folder where the acwcksum.exe file is located, type acwcksum at the prompt. This will start the checksum generator program. You should get several lines printed out, at the bottom it will say Checksum : xxxxx This is the checksum number for the map file.
  3. Add the Corinth modifier of 1559 to this number and using a text editor replace the fourth number in the third line of the map file with this number and save the file.


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Kennon Whitehead's Checksum Generator Program


Kennon Whitehead has put together a Windows program that will generate a checksum number for your map files. This is a Windows based program but it requires .Net Framework 2.0 be installed on your computer. Windows .NET Framework 2.0 is supported on the following platforms: Windows 2000 Service Pack 3; Windows 98; Windows 98 SE; Windows ME; Windows Server 2003; Windows XP Service Pack 2. This download is available at the Windows Update site. If you have a Vista machine .NET Framework 3.0 is included as part of the Windows Vista operating system; you can install it or uninstall it using Windows Features Control Panel. I have installed .Net 3.0 on one of my computers and the Checksum Generator works fine with it. I have also ran the Checksum Generator on Win 7 and Win 10 machines and it worked fine on both.

Once you have installed the .net framework and extracted the Checksum Generator program when you double click the program to start it you should see this

Initial screen

The program defaults to as the file name. If you click on the Browse button you'll see something like this

Browse screen

You can use this window like any Open screen to locate the file you wish to load. Once you select a file you will see something like this

Browse screen

When you hit the Run button you will see a progress bar at the bottom in case you are doing a really big file and need some feed back.

Browse screen

The application will do some error checking. The results are indicated by color of the "Section" checkboxes. As the program process each one of the twelve sections it will check off the corresponding box indicating it found data within that section. Any problems or information about that section will be indicated by these colors:
  1. Blue Indicates the section was correctly flagged as not having data.
  2. Red Indicates that at least one line of section had bad column count.
  3. Dk Red Indicates that the section's row count was off.

The program also displays some of the header information from the first lines of the MAP file along with the final Checksum results. Two results are displayed. The upper one is the unadjusted Checksum value. The lower is the Checksum number you must enter into the third line of the MAP file to make it acceptable to Corinth and includes the Corinth modifier.

Kennon's Checksum Generator Program can be downloaded


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Page designed and maintained by Ken Miller
Last updated 07/26/2020

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