comp.lang.idl-pvwave archive - RDF feed
type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: Getting mean from HDF SD files - stack in envi or read into IDL array?
items: Re: Getting mean from HDF SD files - stack in envi or read into IDL array?

Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: Hi I am extremely new to IDL (2 weeks!) and have previously only used envi on a small scale. I want to read one SD dataset from from a each of a huge number of MODIS files and having looked at IDL and envi batch routines can't decide which is the best way. Bear in mind my limited knowledge and a very short timeframe.... Should I write an envi batch programme and create a big (3000bands +) envi file or should I put straight into the an IDL array. I need to get a mean value (one image or array) and even if it is easier in envi batch mode, would the routine ENVI_SUM_DATA_DOIT with the Mean option deal with the missing values??? Looking at IDL I have managed to open HDF file from command line, read in appropriate data set to an array but how then could I build 3D array from absolutely loads of 2D arrays. Big questions I know - I am desperate to do this in a short time. Any help on any aspect much appreciated. K
creator: kathryn.davies1
date: 2008-07-04T13:41:32-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > Hi > > I am extremely new to IDL (2 weeks!) and have previously only used > envi on a small scale. > > I want to read one SD dataset from from a each of a huge number of > MODIS files and having looked at IDL and envi batch routines can't > decide which is the best way. Bear in mind my limited knowledge and a > very short timeframe.... Should I write an envi batch programme and > create a big (3000bands +) envi file or should I put straight into the > an IDL array. I need to get a mean value (one image or array) and > even if it is easier in envi batch mode, would the routine > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing > values??? > > Looking at IDL I have managed to open HDF file from command line, read > in appropriate data set to an array but how then could I build 3D > array from absolutely loads of 2D arrays. > > Big questions I know - I am desperate to do this in a short time. > > Any help on any aspect much appreciated. > > K Tell me more about how many bands you have in HDF file and how many bands you want to read into IDL?
creator: bulrushmower
date: 2008-07-05T15:33:07-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > > > > > >> Hi > >> I am extremely new to IDL (2 weeks!) and have previously only used >> envi on a small scale. > >> I want to read one SD dataset from from a each of a huge number of >> MODIS files and having looked at IDL and envi batch routines can't >> decide which is the best way. Bear in mind my limited knowledge and a >> very short timeframe.... Should I write an envi batch programme and >> create a big (3000bands +) envi file or should I put straight into the >> an IDL array. I need to get a mean value (one image or array) and >> even if it is easier in envi batch mode, would the routine >> ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >> values??? > >> Looking at IDL I have managed to open HDF file from command line, read >> in appropriate data set to an array but how then could I build 3D >> array from absolutely loads of 2D arrays. > >> Big questions I know - I am desperate to do this in a short time. > >> Any help on any aspect much appreciated. > >> K > > Tell me more about how many bands you have in HDF file and how many > bands you want to read into IDL?- Hide quoted text - > > - Show quoted text - Well I am going to be using around 3-4000 MODIS HDF files but I only want one band (the first) from each i.e. the Land Surface Temperature. Since my last post I have thought about creating a huge multiband file in ENVI and then exporting as a variable to IDL (if the ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with missing values very well, I need them to not be counted as opposed to counting as zero). However that means extracting the SD dataset from all of the HDF files, converting them to ENVI standard files to build multi-band image. I hope the data values are not corrupted by being converted to ENVI standard. Also I could create an image stack in iIMAGE or mess about with iDataManager in some way but they do not s…
creator: kathryn.davies1
date: 2008-07-05T15:46:04-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > > > > > >> On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>> Hi > >>> I am extremely new to IDL (2 weeks!) and have previously only used >>> envi on a small scale. > >>> I want to read one SD dataset from from a each of a huge number of >>> MODIS files and having looked at IDL and envi batch routines can't >>> decide which is the best way. Bear in mind my limited knowledge and a >>> very short timeframe.... Should I write an envi batch programme and >>> create a big (3000bands +) envi file or should I put straight into the >>> an IDL array. I need to get a mean value (one image or array) and >>> even if it is easier in envi batch mode, would the routine >>> ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>> values??? > >>> Looking at IDL I have managed to open HDF file from command line, read >>> in appropriate data set to an array but how then could I build 3D >>> array from absolutely loads of 2D arrays. > >>> Big questions I know - I am desperate to do this in a short time. > >>> Any help on any aspect much appreciated. > >>> K > >> Tell me more about how many bands you have in HDF file and how many >> bands you want to read into IDL?- Hide quoted text - > >> - Show quoted text - > > Well I am going to be using around 3-4000 MODIS HDF files but I only > want one band (the first) from each i.e. the Land Surface > Temperature. Since my last post I have thought about creating a huge > multiband file in ENVI and then exporting as a variable to IDL (if the > ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with > missing values very well, I need them to not be counted as opposed to > counting as zero). However that means extracting the SD dataset from > all of the HDF files, converting them to ENVI standard files to build > multi-band image. I hope the data values are not corrupted by being > converted to ENVI standard. …
creator: bulrushmower
date: 2008-07-05T18:58:11-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote: > On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > > > >> On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > >>> On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>>> Hi > >>>> I am extremely new to IDL (2 weeks!) and have previously only used >>>> envi on a small scale. > >>>> I want to read one SD dataset from from a each of a huge number of >>>> MODIS files and having looked at IDL and envi batch routines can't >>>> decide which is the best way. Bear in mind my limited knowledge and a >>>> very short timeframe.... Should I write an envi batch programme and >>>> create a big (3000bands +) envi file or should I put straight into the >>>> an IDL array. I need to get a mean value (one image or array) and >>>> even if it is easier in envi batch mode, would the routine >>>> ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>>> values??? > >>>> Looking at IDL I have managed to open HDF file from command line, read >>>> in appropriate data set to an array but how then could I build 3D >>>> array from absolutely loads of 2D arrays. > >>>> Big questions I know - I am desperate to do this in a short time. > >>>> Any help on any aspect much appreciated. > >>>> K > >>> Tell me more about how many bands you have in HDF file and how many >>> bands you want to read into IDL?- Hide quoted text - > >>> - Show quoted text - > >> Well I am going to be using around 3-4000 MODIS HDF files but I only >> want one band (the first) from each i.e. the Land Surface >> Temperature. Since my last post I have thought about creating a huge >> multiband file in ENVI and then exporting as a variable to IDL (if the >> ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with >> missing values very well, I need them to not be counted as opposed to >> counting as zero). However that means extracting the SD dataset from >> all of the HDF files, converting them to ENVI standard files to build >> multi-band image.…
creator: bulrushmower
date: 2008-07-05T19:45:19-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 5, 2:45 pm, bulrushmo...@gmail.com wrote: > On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote: > > > > > >> On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > >>> On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > >>>> On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>>> > Hi > >>>> > I am extremely new to IDL (2 weeks!) and have previously only used >>>> > envi on a small scale. > >>>> > I want to read one SD dataset from from a each of a huge number of >>>> > MODIS files and having looked at IDL and envi batch routines can't >>>> > decide which is the best way. Bear in mind my limited knowledge and a >>>> > very short timeframe.... Should I write an envi batch programme and >>>> > create a big (3000bands +) envi file or should I put straight into the >>>> > an IDL array. I need to get a mean value (one image or array) and >>>> > even if it is easier in envi batch mode, would the routine >>>> > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>>> > values??? > >>>> > Looking at IDL I have managed to open HDF file from command line, read >>>> > in appropriate data set to an array but how then could I build 3D >>>> > array from absolutely loads of 2D arrays. > >>>> > Big questions I know - I am desperate to do this in a short time. > >>>> > Any help on any aspect much appreciated. > >>>> > K > >>>> Tell me more about how many bands you have in HDF file and how many >>>> bands you want to read into IDL?- Hide quoted text - > >>>> - Show quoted text - > >>> Well I am going to be using around 3-4000 MODIS HDF files but I only >>> want one band (the first) from each i.e. the Land Surface >>> Temperature. Since my last post I have thought about creating a huge >>> multiband file in ENVI and then exporting as a variable to IDL (if the >>> ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with >>> missing values very well, I need them to not be counted as opposed to >>> counting as zero). However that means extracting the SD …
creator: bulrushmower
date: 2008-07-05T21:32:48-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 5, 10:32 pm, bulrushmo...@gmail.com wrote: > On Jul 5, 2:45 pm, bulrushmo...@gmail.com wrote: > > > > > >> On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote: > >>> On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > >>>> On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > >>>> > On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>>> > > Hi > >>>> > > I am extremely new to IDL (2 weeks!) and have previously only used >>>> > > envi on a small scale. > >>>> > > I want to read one SD dataset from from a each of a huge number of >>>> > > MODIS files and having looked at IDL and envi batch routines can't >>>> > > decide which is the best way. Bear in mind my limited knowledge and a >>>> > > very short timeframe.... Should I write an envi batch programme and >>>> > > create a big (3000bands +) envi file or should I put straight into the >>>> > > an IDL array. I need to get a mean value (one image or array) and >>>> > > even if it is easier in envi batch mode, would the routine >>>> > > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>>> > > values??? > >>>> > > Looking at IDL I have managed to open HDF file from command line, read >>>> > > in appropriate data set to an array but how then could I build 3D >>>> > > array from absolutely loads of 2D arrays. > >>>> > > Big questions I know - I am desperate to do this in a short time. > >>>> > > Any help on any aspect much appreciated. > >>>> > > K > >>>> > Tell me more about how many bands you have in HDF file and how many >>>> > bands you want to read into IDL?- Hide quoted text - > >>>> > - Show quoted text - > >>>> Well I am going to be using around 3-4000 MODIS HDF files but I only >>>> want one band (the first) from each i.e. the Land Surface >>>> Temperature. Since my last post I have thought about creating a huge >>>> multiband file in ENVI and then exporting as a variable to IDL (if the >>>> ENVI_SUM_DOIT doesn't work for the mean, as it may not deal with >>>> missing values very wel…
creator: kathryn.davies1
date: 2008-07-06T09:10:24-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 6, 4:10 am, kathryn.davi...@googlemail.com wrote: > On Jul 5, 10:32 pm, bulrushmo...@gmail.com wrote: > > > > > >> On Jul 5, 2:45 pm, bulrushmo...@gmail.com wrote: > >>> On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote: > >>>> On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > >>>> > On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > >>>> > > On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>>> > > > Hi > >>>> > > > I am extremely new to IDL (2 weeks!) and have previously only used >>>> > > > envi on a small scale. > >>>> > > > I want to read one SD dataset from from a each of a huge number of >>>> > > > MODIS files and having looked at IDL and envi batch routines can't >>>> > > > decide which is the best way. Bear in mind my limited knowledge and a >>>> > > > very short timeframe.... Should I write an envi batch programme and >>>> > > > create a big (3000bands +) envi file or should I put straight into the >>>> > > > an IDL array. I need to get a mean value (one image or array) and >>>> > > > even if it is easier in envi batch mode, would the routine >>>> > > > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>>> > > > values??? > >>>> > > > Looking at IDL I have managed to open HDF file from command line, read >>>> > > > in appropriate data set to an array but how then could I build 3D >>>> > > > array from absolutely loads of 2D arrays. > >>>> > > > Big questions I know - I am desperate to do this in a short time. > >>>> > > > Any help on any aspect much appreciated. > >>>> > > > K > >>>> > > Tell me more about how many bands you have in HDF file and how many >>>> > > bands you want to read into IDL?- Hide quoted text - > >>>> > > - Show quoted text - > >>>> > Well I am going to be using around 3-4000 MODIS HDF files but I only >>>> > want one band (the first) from each i.e. the Land Surface >>>> > Temperature. Since my last post I have thought about creating a huge >>>> > multiband file in ENVI and then exporting as a vari…
creator: bulrushmower
date: 2008-07-06T13:25:48-00:00

Re: Getting mean from HDF SD files - stack in envi or read into IDL array?
type: item
description: On Jul 6, 2:25 pm, bulrushmo...@gmail.com wrote: > On Jul 6, 4:10 am, kathryn.davi...@googlemail.com wrote: > > > > > >> On Jul 5, 10:32 pm, bulrushmo...@gmail.com wrote: > >>> On Jul 5, 2:45 pm, bulrushmo...@gmail.com wrote: > >>>> On Jul 5, 1:58 pm, bulrushmo...@gmail.com wrote: > >>>> > On Jul 5, 10:46 am, kathryn.davi...@googlemail.com wrote: > >>>> > > On Jul 5, 4:33 pm, bulrushmo...@gmail.com wrote: > >>>> > > > On Jul 4, 8:41 am, kathryn.davi...@googlemail.com wrote: > >>>> > > > > Hi > >>>> > > > > I am extremely new to IDL (2 weeks!) and have previously only used >>>> > > > > envi on a small scale. > >>>> > > > > I want to read one SD dataset from from a each of a huge number of >>>> > > > > MODIS files and having looked at IDL and envi batch routines can't >>>> > > > > decide which is the best way. Bear in mind my limited knowledge and a >>>> > > > > very short timeframe.... Should I write an envi batch programme and >>>> > > > > create a big (3000bands +) envi file or should I put straight into the >>>> > > > > an IDL array. I need to get a mean value (one image or array) and >>>> > > > > even if it is easier in envi batch mode, would the routine >>>> > > > > ENVI_SUM_DATA_DOIT with the Mean option deal with the missing >>>> > > > > values??? > >>>> > > > > Looking at IDL I have managed to open HDF file from command line, read >>>> > > > > in appropriate data set to an array but how then could I build 3D >>>> > > > > array from absolutely loads of 2D arrays. > >>>> > > > > Big questions I know - I am desperate to do this in a short time. > >>>> > > > > Any help on any aspect much appreciated. > >>>> > > > > K > >>>> > > > Tell me more about how many bands you have in HDF file and how many >>>> > > > bands you want to read into IDL?- Hide quoted text - > >>>> > > > - Show quoted text - > >>>> > > Well I am going to be using around 3-4000 MODIS HDF files but I only >>>> > > want one band (the first) from each i.e. the Land Surface >>>> > > Temperature. Sinc…
creator: kathryn.davies1
date: 2008-07-06T22:38:17-00:00