GREAT-ER: Catchment data pre-processing

Catchment data pre-processing

The preparation of a catchment dataset to be incorporated in GREAT-ER requires a sound pre-processing to ensure a high level of integrity.

Software package greater-pre-processing

Current stable version is 1.2.0.

Stable version as a tar.gz-file and a comprehensive documentation as pdf-file are available from the ftp site. Most recent development version available via SVN (see here on how to get current sources).

Requires:
Python >= 2.2.1
GNU Awk >= 3.1.0
gen2shp >= 0.3.0
txt2dbf >= 1.0.2
dbf2txt >= 0.5.2
GNU sed >= 3.02
GNU textutils (sort, join, cut, paste) >= 2.0
GNU fileutils (rm) >= 4.1
GNU sh-utils (echo) >= 2.0.11
(the programs must be somewhere in your search path)

License: GNU General Public License (GPL)

The file Howto describes how to use the tool.

Catchment source files format

[ catchment.desc | .drn | .rna | .dsd | .cbp | .lks | .pic | .bgd ]

Note: This new format slightly differs from the original GREAT-ER 1 format and is therefore not fully compatible. See changes.

All 6 catchment source files have to be collected in one directory.

All files are text based and use the character set ISO 8859-1 (ISO Latin 1). The format is line-oriented; each line starts with a '#' (comment line) and all empty lines have no meaning for the processing and can be inserted anywhere.

All coordinates are given in the same projection: "geographic projection" with unit "dd" (decimal degrees). A point, rather than a comma, is used as decimal point. Numbers are not allowed to contain any other delimiters. Exponential representation uses the letter 'E' or 'e'.

Info file catchment.desc

This file contains general information. Example:

ID=went
NAME=Catchment of River Went
DESCRIPTION=The Went catchment is a small, rural area in Yorkshire, UK.
IN-VERSION=1.0
OUT-VERSION=1.0

ID is the basename for the actual data source files suffixed with .drn, .rna, .dsd, .cbp and .bgd. VERSION defines the Format for the all catchment source files.

Digital river network (ID.drn)

The river network attributes are stored in a simple tabular structure. Columns are separated by commas. The following example illustrates the order of the columns:

7421
-1.399004,53.718807
-1.374895,53.730835
-1.368942,53.734528
-1.364163,53.736794
-1.363446,53.738102
6787
-1.399046,53.717968
-1.399043,53.718178
[...]

River network attributes (ID.rna)

The river network attributes are stored in a simple tabular structure. Columns are separated by commas. The following example illustrates the order of the columns:

# Aire/Calder Catchment, Yorkshire
# StretchID,Qmean(m^3/s),Q5(m^3/s),vmean(m/s),v5(m/s),
# ... RealLength(m),depthmean(m),depth5(m),Name
26954,34.751000,12.280656,,,2491.655000,,,Unnamed         
22954,0.009000,0.002359,,,1648.222000,,,Unnamed         
7333,34.739000,12.276415,,,1629.885000,,,Unnamed         
22932,0.005000,0.001088,,,540.190000,,,Unnamed         
26950,34.731000,12.274977,,,2336.740000,,,Unnamed         
22923,0.017000,0.002167,,,2447.520000,,,Unnamed         
[...]

In this example no information is available for flow velocity and depth and hence the corresponding columns are left empty.

Discharge site data (ID.dsd)

Each line defines one discharge. The first column is its unique ID, followed by the coordinate pair and the attributes. The order of the columns is shown in this example:

# ID,X,Y,Pop,DWF(m^3/d),Flow(m^3/d),Type,StretchID,Name
41,-1.390494,53.422081,422677,130000,180000,AS,26842,Blackburn STW
42,-1.349155,53.369724,95750,21800,24506,AS,26843,Woodhouse Mill STW
43,-1.326922,53.445114,107203,31250,32410,AS,26841,Aldwarke STW

Catchment boundary polygon (ID.cbp)

The polygon is described linewise by single coordinate pairs (x,y). The following example illustrates the format:

-2.052912,53.683811
-2.060483,53.683807
-2.060477,53.679314
-2.068047,53.679310
[...]
-2.045346,53.688309
-2.045342,53.683804
-2.052912,53.683811

This example also shows that the polygon must be closed, cf. the last and the first point must be identical.

Lakes (ID.lks)

A list of stretch IDs which actually are lakes. Example:

# StretchID
345
2256

This file can be empty, but must exist.

Pictures (ID.pic)

If pictures are available for the catchment, location and picture files can be specified:

# ID,X,Y,File,Name
1,6.860403,51.157661,mgmuendung.jpg,Confluence to the Rhine
3,6.872726,51.158089,mgddorf.jpg,in Duesseldorf
4,6.897292,51.159611,uhilden1.jpg,Below STP Hilden
5,6.899222,51.159081,uhilden2.jpg,Below STP Hilden

This file can be empty, but must exist.
Note, that the picture files must be in jpg-format.

Background data (ID.bgd)

To support the user with a quick and easy access to geographic background information, a list of background data sets can be defined for each catchment.

In the ".bgd" file names of additional background data that are to be loaded by the menu entry "Display/Add Background Data" are specified. The data can be given in two ways. In a simple case, a background data set is only a geographic data set that ArcView can load as a theme, i.e. anArcInfo Coverage, an image, a grid or a shapefile. This case is indicated by the value "yes" in the field "ctch_flg" (see below). In the more complex case a background data set consists of a set of geographic data, indicated by the value 'no' in the field 'ctch_flg'. In this case, instead of the name of the data set an ID for a script that knows how to load the geo-data sets is specified.

Name

This is the name for the corresponding background data. It is used for user selections in the GREAT-ER system.

Mapname

In the case of a simple background data set, this is the file name of the coverage, image or shapefile that contains the data. Otherwise this field contains the script which can load the background data sets.

Type

In the case of a simple background data set, this is its feature type. Valid entries are "point", "line", "polygon", "shape", "image" and "grid". Otherwise the field is left empty.

Legendfile

In the case of a simple background data set, this is the name of an optional ArcView legend file. Otherwise this field can contain (optional) parameters for the script specified in the field "Mapname".

ctch_flg

This is a boolean field that contains either "yes" or "no". "yes" indicates that this background data set consists of one theme that does not need a special script to load into the active view of GREAT-ER. "no" means that a special Avenue script has been developed by the user which runs within GREAT-ER and loads the backgroud data set into the active view.

There is one special case: The DCW data (Digital Chart of the World, a variant of VMAPL0) are incorporated in the GREAT-ER project for the whole of Europe. For this incorporation specific scripts loading the DCW data in dependence of the viewed country are developed. If the DCW data are to be a background data set for a catchment, the following line needs to be inserted into the file:

DCW data,,,,

If a user installs the DCW data for countries that have not yet been included, e.g. France, Spain or Denmark, these data need to be installed analogous to the included countries.

Example ".bgd" file

This example file describes background information for the River Itter (Germany):

#River Itter background data
#Name,Mapname,Type,Legendfile,ctch_fl
Cities,itter\cities,polygon,itter\cities.avl,yes
Tk25,itter\tk25tiffz.tif,image,,yes
Rhein,itter\rhein,polygon,itter\rhein.avl,yes
DCW data,,,,no

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