As a result of the need for a variety of consistent high resolution land masks and related files, the Scatterometer Climate Record Pathfinder project has created a number of land mask files based on the 1987 CIA World Database II. As described below, several file types are available for general use from our web site: ftp.scp.byu.edu/pub/data/misc/maps/    A README.txt file is included in the directory. The files are gzipped and will need to be gunzipped before using. Sizes shown below are the ungzipped files sizes. The gzipped sizes are much smaller. Landmasks for other standard SCP regions are derived from these files.

Land Distance Map (Byte Map)

A file containing one byte per pixel on a 0.01 deg by 0.01 deg grid that gives the distance to the nearest land in km. Values larger than 255 are clipped to 255. Land is 0.
WorldLandDistMap.gz [648MB]

Byte map file with a 0.01 deg x 0.01 deg map of distance to nearest land in km. File was created from CIA world coastline database by plotting coastlines into 0.01 deg x 0.01 deg binary array. Adobe Photoshop was then used to "fill" enclosed land areas. For each ocean pixel a brute force search was used to find the distance to the nearest land which was clipped to 255 km.

A Matlab script to plot the data is given in plot_WorldLandDistMap.m

Land Mask (Bit Map)

Two files containing binary flags stored in 32 bit integers, one in big endian rrder, the other in little endian byte order.
WorldLandBitMapBE.dat.gz [81MB] (big endian byte order)
WorldLandBitMapLE.dat.gz [81MB] (little endian byte order)

Binary bitmap file with a 0.01 deg x 0.01 deg map of land (=0) and water (=1). File was created from CIA world coastline database by plotting coastlines into 0.01 deg x 0.01 deg binary array. Adobe Photoshop was then used to "fill" enclosed land areas. The bit map was then written as 32 bit integers in row major order. Each 32 bit integer thus contains flags for 32 longitude positions spanning 0.32 deg. Land masks for other SCP regions are derived from this map by compute the latitude and longitude for the center of each pixel in a standard SCP region, then "looking up" this latitude and longitude position in the WorldLandBitMap array. The land/water value of the nearest position in the array is returned.

A Matlab script to plot the data is given in plot_WorldLandBitMap.m

Coast/River Outline

Two files, one with longitudes expressed 0..360 and the other using -180..180, that have contigous coastlines, river outlines, glaciers, etc. are available.
ciaworld000.dat.gz [64MB]
ciaworld180.dat.gz [64MB]

ASCII files containing list of (lat,lon,pen,Code) values that describe world coastlines and rives. The data convention is the conceptal plotting of a pen with the pen "down" from the previous point to the current point when pen=2, and moving the pen with the pen up when pen=3. The Code value, is described below. This data set is essentially equivalent to the original cia world data base combined into one file and in an ASCII format. A few minor corrections have been made including the removal of the grounded B10A iceberg from the database. Note: ice sheet edges, glaciers, and river positions are dated to the early 1980s.

A Matlab script to plot the data is given in plot_ciaworld.m

Code	General Type
1	Coasts
2	Add Major island
3	Intermed islands
4	Minor islands
5	Double-line Rivers
6	Intermit major lake
7	Intermit minor lake
8	Reefs
9	Major Salt pans
10	Minor Salt pans
11	Lessor Canals
13	Major Ice Shelve
14	Minor Ice Shelve
15	Glaciers