ITC work
Projects

AHAS Project    

snapshots

Major goals: software development for AVHRR applications in hydrology; expert system guidance; multi-level approach; universal applicability for regional hydrological studies.

General

• ITC-BCRS funded. (1999-2000). Successfully finished.
• Participants:
  • Netherlands: ITC - LUW
  • Sri Lanka: IMWI - Department of Meteorology

Antecedents

The coarse spatial resolution (1 km) solar-synchronic satellite NOAA-AVHRR provides daily global coverage (twice or more) at an affordable cost. AVHRR was designed for meteorological purposes and sea applications, but very soon the low image cost (available in INTERNET nowadays), free image shot policy, frequent acquisition and adequate radiometric resolution made this satellite very attractive for many scientific community branches focused on regional applications.

The amount of scientific research and effort done to expand the capability of AVHRR images to land applications in the past two decades was enormous. Many methods were developed for specific use with this sensor. All this effort was published but spread out in the specialized literature and journals. Due to International character of ITC we were receptive to the need of an adequate tool able to compile these methods and deal with the spatial variations of hydrological parameters in areas of data scarcity. There was a need then to develop a system to post-process AVHRR from raw data to a full hydrological outputs for training purposes, hydrologists, decision makers or watershed managers.

Main Objectives

• To compile the most practical and universal methodologies applied to hydrology management from AVHRR raw data.
• To establish a range of applicability of these procedures.
• To build an expert system (ES) to guide the user through the different techniques dimishing the need of specialized user skills.
• To develop a friendly project-based User Interface (UI) able to post-process raw AVHRR imagery take to full hydrological outputs in a thematic environment.
• Build a very dedicated help file containing full explanation of each method, links to relevant Internet sites and built-in spreadsheet for training purposes.

AHAS structure

An AHAS operation consists on seven steps, five of them are fully automatic and two require decisions from the user.

1. Through the UI the user selects certain output from the thematic menu.
2. The UI activates the subroutine containing the selected methodology.
3. The ES searches the existing files into the current AHAS project to offer adequate input data (values, maps, tables, etc.) to the user.
4. The available data is presented in a dedicated dialog box for final user check. 
5. The user changes the default input (if necessary). Eventually the user has to take decisions as required for some methodologies. In all cases the ES will offer adequate defaults. At the end, the user gives 'OK' to initiate the calculations.
6. The UI transfer the inputs and procedures to ILWIS through DDE technology and scripts. ILWIS does the automatic operations to produce the outputs.
7. The final outputs are incorporated the current AHAS project and added to the thematic catalogue. The user accesses it through the UI.

Input data required by one AHAS project

In total 11 raster maps are required. The downloading AVHRR software is mostly capable to built the input to AHAS. Whatever the case the maps have to built outside AHAS and then imported into the current project (one project = one image take)

• 2 Top Of the Atmosphere (TOA) narrow band albedo maps (ch1 & ch2)
• 2 Atmospherically Corrected (AC) narrow band albedo maps (ch1ac & ch2ac)
• 3 TOA surface brightness maps (ch3, ch4 & ch5).
• 4 angle maps: solar & satellite zenith angle maps and solar & satellite azimuth angle maps

Outputs from AHAS

The outputs in AHAS are organized by 7 thematics menus. At present only 5 menus are operational.

AHAS courses

Although AHAS is relatively easy to use, it consists of many steps. In some steps choices are offered. The dedicated Help file is fully self explanatory, and includes exercises and spreadsheet practicals. However the WRES Division prepared a dedicated module (short course) in the AHAS software that includes:

• Lectures given by the AHAS authors (ITC-WRES staff).
• Lecture material and methods.
• Study cases.
• The ILWIS, AHAS and complementary packages.

AHAS course link

AHAS characteristics

• PC software
• OS: Windows 95-98-2000-NT.
• Language: Visual Basic - ILWIS (RS/GIS) operating in parallel at background.
• ILWIS data base.
• Built-in expert system guidance.
• Catalogue function for easy-to-use file keeping
• Thematic menus.
• Import-export capabilities from all main GIS-RS formats.
• Full printing capabilities.
• Full descriptive help on-line: theory, inputs, exercises, top links.

And ... last but not least...

• A full GIS-RS software (ILWIS) works at the background. It can also be used independently from AHAS, expanding enormously the software capabilities.

Pricing

AHAS is freeware (as from March 1 2002) but requires the ILWIS package. Consult ILWIS pricing in the ILWIS home page.

Interested?... contact Anneke Nikijuluw mailto:nikijuluw@itc.nl  

ASTIMwR project

snapshots

Major goals: Detection of irrigated areas; irrigation efficiency; crop water requirements; user identification; aquifer depletion

General

• EC funded. (1997-2000). Successfully finished.
• Participants:
  • Spain: Geosys (PM) - CHG - IDR (UCLM)
  • Portugal: INAG
  • Italy: UNAP II - Consorzio Bonifica di Paestum (CBP)
  • Netherlands: ITC - WSC-DLO
• FW areas
  • Guadiana Basin (Spain-Portugal) 63,000  km²
  • Extrapolation area: CBP irrigation district (Italy)

Origin of the problem

The Spanish Water Law stated a change in water ownership from the private to the public sector after severe groundwater depletion in the semi-arid Spain. Overexploited aquifers are becoming a world-wide problem, in this thirsty millennium.

The change was problematic.  The  Water Law considered the rights of the pre-existent exploitations before 1985. No or few drilling records were available and as a consequence an uncontrolled exploitation wave appeared everywhere. The aquifer reached its lowest-ever level in 1995. According to records the depletion was more than 40 m in certain areas, some of them well known national parks.

Main Objectives

• To develop a User Interface (UI) for daily Watershed Management on a routine basis at the customers organizations: CHG - INAG - CBP
• To produce state-of-the-art irrefutable proves of water abuse for potential trials.

Project toolbox

• RS techniques to detect hydrological pre-existent situation (before 1985).
• GIS-DBASE techniques to produce digital cadastral databases.
• Arial photo interpretation and land surveillance for detailed evaluation.
• RS-SEBAL modeling to evaluate medium-term actual evapotranspiration and crop consumption.
• Agronomical-hydrological models to evaluate short-term actual evapotranspiration, crop consumption and irrigation efficiencies.
• Advance database management to store and retrieve historical and new user and climatic information in a practical manner.

Main UI applications

• Irrigation detection: new/old schemes - user identification - user legal status.
• Irrigation quantification: GIS/RS/SEBAL model application.
• Evapotranspiration studies: SEBAL algorithm.
• On-line climatological, surface and groundwater database.
• Evolution of protected environments (national parks)
• Aquifer evolution: multi-temporal analysis
• Advance: GIS and RS full functions

Main characteristics of the User Interface

• PC - OS: Windows 98.
• Language: Visual Basic - ILWIS (RS/GIS) operating in parallel at background.
• Access data base.
• Designed for non-skill operators.