Overview
This import is available in DELFT-FEWS versions after 28-1-2007
Imports time series data (grids) ArcInfoAscii files. The time and parameter information are encoded in the filename. Example:
Rain_20071010231500.asc (parameterId_YYYYMMDDHHMMSS.extension) |
---|
parameterId = Rain |
year = 2007 |
month = 10 |
day = 10 |
hours = 23 |
min = 15 |
sec = 00 |
This import always uses the locationid ARC_INFO_LOC as the external location. The import can read from a zip stream. As such, you can multiple grids within a single .zip file. Useful for large amounts of grids or very large grids.
Configuring the Import
The reader is named ArcInfoAsciiGrid which should be configured in the general section of the import: <importType>ArcInfoAsciiGrid</importType>.
Example:
<?xml version="1.0" encoding="UTF-8"?> <timeSeriesImportRun xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fewshttp://fews.wldelft.nl/schemas/version1.0/timeSeriesImportRun.xsd"> <import> <general> <importType>ArcInfoAsciiGrid</importType> <folder>Import</folder> <idMapId>IdImportSidbAsc</idMapId> <geoDatum>Ordnance Survey Great Britain 1936</geoDatum> </general> <timeSeriesSet> <moduleInstanceId>ImportSidbAsc</moduleInstanceId> <valueType>grid</valueType> <parameterId>P.radar.actual</parameterId> <locationId>ARC_INFO_LOC</locationId> <timeSeriesType>external historical</timeSeriesType> <timeStep unit="minute" multiplier="15"/> <readWriteMode>add originals</readWriteMode> </timeSeriesSet> </import> </timeSeriesImportRun>
As the file format does not include geographical datum information you must configure the geoDatum field in the general section
The IdMapping file should always refer to the external location ARC_INFO_LOC.
Example:
<?xml version="1.0" encoding="UTF-8"?> <idMap version="1.1" xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fews http://fews.wldelft.nl/schemas/version1.0/idMap.xsd"> <parameter external="CEH" internal="P.radar.actual"/> <location external="ARC_INFO_LOC" internal="My_Location"/> </idMap>
The file format
Introduction
ARC ASCIIGRID refers to a specifc interchange format developed for ARC/INFO rasters in ASCII format. The format consists of a header that specifies the geographic domain and resolution, followed by the actual grid cell values. Usually the file extension is .asc.
ncols 157 nrows 171 xllcorner -156.08749650000 yllcorner 18.870890200000 cellsize 0.00833300 0 0 1 1 1 2 3 3 5 6 8 9 12 14 18 21 25 30 35 41 47 53 59 66 73 79 86 92 97 102 106 109 112 113 113 113 111 109 106 103 98 94 89 83 78 72 67 61 56 51 46 41 37 32 29 25 22 19 etc...
Geographic header
Coordinates may be in decimal or integer format.
ncols xxxxx
ncols refers to the number of columns in the grid and xxxxx is the numerical value
nrows xxxxx
nrows refers to the number of rows in the grid and xxxxx is the numerical value
xllcorner xxxxx
xllcorner refers to the western edge of the grid and xxxxx is the numerical value
yllcorner xxxxx
yllcorner refers to the southern edge of the grid and xxxxx is the numerical value
cellsize xxxxx
cellsize refers to the resolution of the grid and xxxxx is the numerical value
nodata_value xxxxx
nodata_value refers to the value that represents missing data and xxxxx is the numerical value. The default is -9999.
Filename pattern
At the moment the filenamepattern is fixed. A very useful tool for easily renaming filenames is Batch Rename Command