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19990729: AVHRR/NDVI and Arc/INFO data

>From: Jimmy Adegoke <address@hidden>
>Organization: Penn State
>Keywords: 199907292205.QAA14340 McIDAS

Jimmy,

>A search using NDVI and Arc/INFO as keywords on your website Q&A search
>engine returned nil hence this e-mail. Two questions:
>
>1.  I have NDVI images (derived from AVHRR level 1B data) which I use in
>ERDAS and would like to bring into MCIDAS. The plan is to look at
>NDVI-convective cloud associations in one software environment. 
>Characteristics of the NDVI data that I'm using include the following:
>
>Units: unitless
>Data Range: -1 to +1
>Data type: 8 bits(unsigned)
>Offset: 128
>Gain: .008
>Bin. min/max: 3/253
># of colums/rows: 1090/820
>
>Note: 8 bit data is scaled - so to obtain actual geophysical values one
>has to subtract the offset from the scaled data value and multiply the
>result by the gain.

To put the data in a McIDAS AREA file format, the data will have to be
scaled appropriately for the number of bytes used to represent the
information (i.e. 0 - 255 for 1 byte, etc.).

>2. I also do some GIS type work in Arc/INFO and was wondering if there are
>utilities avalable to convert an ARC polygon or point coverage into a
>format that McIDAS can read.

Not that I know of.

>The goal here is to look at surface (land
>cover) influences on convective cloud initiation/dissipation.  
>
>I can place samples NDVI composite image and ARC coverages in my outgoing
>ftp directory for download if you require me to do so. 

I will not have time to look into this until after the McIDAS workshop
finishes a week from Saturday.

>Thanks for your help.  

See you at the workshop.

>Jimmy Adegoke
>Climate Program
>Geog. Dept. & Earth System Sc.Center
>302 Walker Building
>The Pennsylvania State University
>University Park PA 16802
>
>e-mail: address@hidden
>Fax: (814) 863-7943; Office Phone: (814) 865-6151

Tom Yoksas