Atlas File Format Description



International Atlas


Each atlas country file starts with "@0500". This is the Astrolog32 file type. This is followed by several lines with comments.


There are three types of comment lines: blank lines, lines starting with a blank, and lines starting with a semi-colon. Comment lines are allowed anywhere in the file except as the first line, and are disregarded by the software. It is not possible to have a comment that occupies only part of a line.

Following the file header, there is a list of administrative regions, which ends in a line starting with "%%". Some small countries do not have administrative regions, otherwise there is one line for each region, which starts with a two-character code, followed by a blank and the name of the administrative region, which goes until the end of the line.

The last section of the file is the list of place names. There is a minimum of one place name for some small countries, and a maximum of around 207 000 for Russia.

Each line has seven fields separated by blanks:
  1. Search Fields - 3 character code explained in the Advanced Settings section. It is exactly the same code as displayed in the list box of place names in the main atlas dialogue box.
  2. Population - either a number or "-" if not available.
  3. Longitude in the format "degree n|s minutes[.seconds]", where "n|s" denotes either North or South, and "[.seconds]" means that seconds are optional, but if they are shown, they are separated from minutes by a dot.
  4. Latitude in the format "degree e|w minutes[.seconds]", where "e|w" denotes either East or West, and the rest is as for Longitude.
  5. Extra Field - this is for future expansion, possibly to store altitude. Currently is always zero and is disregarded by the program, but must be present.
  6. Administrative region - two character code that must match one of the codes defined in the first section of the file, or else be "00".
  7. Place name, which may include blanks, commas, apostrophes, etc. It is terminated by the end of the line.

Atlas files are published as read-only files, to prevent accidental modification. They can be manually modified, however any modification should be done with great care or the software will not operate properly. The reason is that, for efficiency, to be able to create lists of thousands of places in a few seconds, no validation is done to the data in the country file.

If you modify country files you should not add any blanks or "strange" characters anywhere, except for place names. Strange characters could be, for example, non-printable characters such as form feed, or tab, punctuation marks, etc.

As part of the place name you may add extra blanks or other printable characters, for example ''#', '&', etc.

The file must be terminated by an empty line.


American Atlas


Each atlas state file starts with "@0600". This is the Astrolog32 file type. This is followed by several lines with comments.

There are three types of comment lines: blank lines, lines starting with a blank, and lines starting with a semi-colon. Comment lines are allowed anywhere in the file except as the first line, and are disregarded by the software. It is not possible to have a comment that occupies only part of a line.

The main section of the file is the list of place names. Each line has seven fields separated by vertical bars (|):
  1. Search field - 3 character code explained in the Advanced Settings section. It is exactly the same code as displayed in the  place names list box in the main atlas dialogue box.
  2. Feature name.
  3. Cell name.
  4. County name.
  5. Longitude in the format "degree n|s minutes[.seconds]", where "n|s" denotes either North or South, and "[.seconds]" means that seconds are optional, but if they are shown, they are separated from minutes by a dot.
  6. Latitude in the format "degree e|w minutes[.seconds]", where "e|w" denotes either East or West, and the rest is as for Longitude.
  7. Altitude in meters.
Some fields may be missing, in which case we may see two vertical bars in sequence, or a vertical bar at the end of the line if the altitude is missing.

Atlas files are published as read-only files, to prevent accidental modification. They can be manually modified, however any modification should be done with great care or the software will not operate properly. The reason is that, for efficiency, to be able to create lists of thousands of places in a few seconds, no validation is done to the data in the state file.

If you modify state files you should not add any blanks or "strange" characters anywhere, except for place names. Strange characters could be, for example, non-printable characters such as form feed, or tab, punctuation marks, etc. Names may include blanks, commas and apostrophes.

The file must be terminated by an empty line.



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