Handling And Cataloging Maps And Datasets For Geonetwork

THL Toolbox > Places & Geography > Map Cataloging

Handling and Cataloging Maps and Datasets for GeoNetwork

Contributor(s): Quentin Devers

We use GeoNetwork to catalogue:

  • paper maps & digital maps
  • interactive maps
  • GIS datasets (vector and raster layers)

For paper & digital maps, follow carefully all steps 1 through 7.

For interactive maps and GIS datasets, follow only steps 1 and 7.

1. Getting the basic information

When you have a new map to catalogue, there are few things you need to find out about it. You can actually catalogue not only paper maps, but also digital maps, datasets (vector and raster), and interactive maps. For that, fill the most up-to-date spreadsheet that you’ll find in the folder “Map Catalogue” in the resources of “GIS-THL” Collab site.

1) Scroll down to last record. In the next available line, create a new ID. The ID has to be in the format M###, i.e. “M” followed by a numeral. 2) Here are the columns:

  • name: If the map has a name, copy it. Otherwise make one up that describes the map.
  • scale: This is the scale indicated in the map. If there’s no scale on the map, then go to the next column.
  • estimated scale: If the map doesn’t have a scale, try to estimate it using Google Earth: measure the distance between two landmarks you have both on the map and that you can see in Google Earth, and, from that, calculate the approximate scale of the map.
  • long min: This the first coordinate of the bounding box of the map. If the map has a grid, use it to see what is the minimum longitude value in the map. If the map doesn’t have a grid, ignore the next three columns and go to the ones after that. It has to be in decimal degrees.
  • long max: This is the maximum longitude value in the map.
  • lat min: This is the minimum latitude value in the map.
  • lat max: This is the maximum latitude value in the map.
  • long min est.: If the map doesn’t have a grid, then try to figure out what are the coordinate of its bounding box using Google Earth. Pay attention to the number of decimals you give, it has to reflect the precision of your measurements.
  • long max est.: This is the maximum longitude value you can estimate.
  • lat min est.: This is the minimum latitude value you can estimate.
  • lat max est.: This it the maximum latitude value you can estimate.
  • projection system: Few maps report their projection systems. If they do, report it here.
  • date of publication: If the map reports when it was published, enter the year of publication here. If it doesn’t, try to determinate between which dates it was published. For example, if you have a map of TAR, it means that it was published after 1951, and before the year in which you are cataloguing it, i.e. 2010 or so. Sometime on a map you’ll have a mention like “borders depicted after 1990 census data”, which means that the map was published after 1990.
  • author: this is the author of the map. Only in a few cases it is written in the map.
  • publisher: this is the publisher of the map.
  • language: language in which the legend is written.
  • physical size of the map: It is the size of the map, in cm (width * height).
  • series: If the map is in several sheets, or if it is part of a series (like the Chinese place name indexes), say it here.
  • inset maps: An inset map is the small map you sometime have, that can show a detail in the map, or that can show where the area depicted is in a larger context.
  • comments: If the map is in a book, write down the reference of the book here. If you have any other comment, write it down here.

You will need all these information later on for our online cataloguing system (GeoNetwork). It is also good to keep this spreadsheet up to date in order to know what ID to give to the map.

When you’re done, update the date in the name of the spreadsheet, and re-upload it to Collab.

2. Scanning, converting in different resolutions

For a map, you need to get it scanned. If it is a digital map, you need to get it at the highest resolution you can. For the datasets and interactive maps, forget about this section.

For the scan, make sure to have a 400ppi TIFF file. If the map has a legend on a separate sheet, make sure to scan it as well.

Once you have it, or once you have the digital map, you need to: 1) convert it in JPEG, with the maximum quality settings. 2) create different versions of this JPEG in different resolutions. For this matter DO NOT modify the size of the image, only its resolution. You need five resolutions: 400ppi (or the highest resolution available, so it can be 300ppi or 800ppi for example), 200ppi, 100ppi, 50ppi and 25ppi. For all of them, always choose the highest quality settings for JPEGs.

3. Preparing the archive

For each map and digital map, you need to make a zip file. This doesn’t concern datasets or interactive maps.

To see an example of such an archive: external link: http://www.thlib.org/static/maps/dls/MXXX-400ppi.zip

So, in an archive you have two, possibly four files:

  • the scan of the map in the highest resolution available.
  • the scan of the legend if it is on a separate sheet.
  • an info PDF file, that reports all the information you wrote down at the beginning.
  • if the map is not in English, a PDF that gives a translation of the legend.

Take the files in this archive as models, and imitate them. You can use Word on a mac for that, and once you’re done just do “Print”, and in the dialog box hit “Save as PDF”.

If a map is in several sheets, then you have to include all the different sheets in a single archive, so that people need to download only one archive. Each sheet is to be included in a separate folder within the archive. To see an example: external link: http://www.thlib.org/static/maps/dls/M8a-M8b-400ppi.zip

4. Georectifying

For both scanned maps and digital maps, you need to georectify them. For this, you need to use Arc View (or any other tool for georectifying images). The end coordinate system has to be WGS1984.

If the map has a grid, then you have to georectify the map based on the grid. The aim is to have the grid lining with the lat-long grid on your software, regardless of what’s depicted on the map.

If the map doesn’t have a grid, then you have to georectify it based on the content of the map. For this the easiest is to use borders, lakes and streams.

5. Naming the files

All the files created have to be named according to the following guidelines.

The core for every file is to hae its ID, for example M55a. Then, different information are added to this core, separated by dashes “–”:

  • the resolution of the image: example: “M55a-200ppi”, “M55a-50ppi”.
  • if the map is on both sides of a sheet, then add “-front” or “-back” after the ID and before the resolution. Example: “M55a-front-200ppi”, “M55a-back-200ppi”.
  • sometime maps have their legend on a different sheet or page. Therefore there is the need to include a scan of this separate legend as well. The rule to name the scanned legend is to add “-legend” after the ID. Example: “M55a-legend-200ppi”.
  • the name of the archive is simply the ID followed by the resolution. Example: M10-400ppi.zip. If the archive includes several sheets: in the archive each sheet is to be held in a separate folder, whose name is the ID of the map foolowed by the resolution (“M8a-400ppi”, “M8b-400ppi” for example). And the name of the archive is: 1) if there are only two sheets: the two IDs separated by a dash, and followed by the resolution (example: “M8a-M8b-400ppi”); 2) if there are more than two sheets then the ID of the first map and the ID of the last map separated by “-to-” and followed by the resolution (example: “M1a-to-M1i-400ppi”). In the archive, you also have the info file: its name is “Info-“ followed by the ID of the map (example: “Info-M55a.pdf”). There can also be a pdf translating the legend if t he map is not in English: its name is “Legend-“ followed by the ID of the map (example: “Legend-M16a.pdf”).
  • finally, for the georectified GIS files, we do not indicate the resolution in the name as we work from the highest available and as the resolution is then altered by the GIS software during the georectifying process to fit the GIS needs. However we do keep the “front” and “back” indications, and we add “-georectified” at the end of the name. Exemples: “M1a-georectified”, “M24a-front-georectified”, “M35-georectified”.

Of course, all these names have to be followed by the extension of the file. As of July 2009, images are in “.jpg”, archives in “.zip”, and text files in “.pdf”. But these format could evolve in the future.

6. Uploading the files to BlueUnix

For questions about how to access BlueUnix, please contact Steve.

In the “thdl.org” folder in BlueUnix, there is a folder “maps”. In this folder you’ll find a series of folders where you can upload all the files you’ve created:

  • the maximum resolution scans go to the folder “300ppi-400ppi”
  • the 200ppi scans go to the folder “200ppi”
  • the 100ppi scans go to the folder “100ppi”
  • the 50ppi scans go to the folder “50ppi”
  • the 25ppi scans go to the folder “25ppi”
  • the archives go to the folder “dls”
  • and the georectified files go to the folder “georectified”

See also external link: Map Folder Structure & Name Conventions

To link these files with public URLs in GeoNetwork, the model is: external link: http://www.thlib.org/static/maps/XXXX

where XXXX is the path to the file.

Example: external link: http://www.thlib.org/static/maps/100ppi/M55a-100ppi.jpg

In the case of copyrighted material, you also have to upload the archives to the folder “zipped_maps” in the Collab site called “THL Map Holding”. Then, the links to them in GeoNetworks have to be the archives on this Collab site.

7. Creating the entry in GeoNetwork

See external link: THL Cataloging Maps System Editorial Manual

Provided for unrestricted use by the external link: Tibetan and Himalayan Library