Richard Stow asks: Can anyone suggest a simple method of exporting pixel values of a 28Mb = IEEE 4byte real ERS/data file for import to Excel. I only have access to = ERM 5.5
Richard I am not sure why you want to move XYZ data from ErMapper to Excel when ErMapper has all the editing tools you need and Excel is limited in the number of rows you can import. I typically work in V5.5 on UNIX with raster files of over 3 million pixels and this massively exceeds Excel's 65536 line import limit on my PC. However to answer your question first Data preparation in ErMapper prior to Raster Export:- If necessary create a raster dataset that contains the processed pixel values that you wish to export and edit in Excel. You MUST ensure that any raster dataset you wish to export from ErMapper has the NULL value set to the default ErMapper NULL value of 1e+10. Other NULL values greater then 1e+10 (e.g. SeisWorks or ZMap Nulls of e+36 & e+37) will be exported as huge integer values in your output text file. If it is required to correct an illegal NULL in ErMapper, you must create a new raster file. Use Process > Rectification > Map to Map Transformation > Rectify Dataset > Rectification Setup and ensure that the OUTPUT Null value is 1e+10 Export to a text file To export raster data from a raster.ers use Utilities > Export Raster > XYZ ASCII grid with NULLS. Set your null to some suitable value. N.B. Use Export with NULLS as it is necessary preserve the NULLS outside ErMapper so that you can automatically re-import your processed data from EXCEL with a full matrix of data and NULLS. Loading and working in Excel I assume that you are an expert Excel user. As you know loading XYZ text files into Excel is easy but watch out for the nasty ErMapper V5.5 export bug that collapses real numbers ending .000000 and writes these out as integers in your text file. (In a dataset of 3 million pixels random chance will ensure that there are some examples of this bug), Fix this problem inside Excel by setting your column format to a REAL decimal number. Remember to preserve the line order when editing in Excel and use file save as Formatted Text (Space delimited) .prn file for your final processed data file output from Excel. Importing back into ErMapper Use Utilities > Import Gridding Formats > XYZ ASCII grid. This import routine automatically reads the entire prn text file to obtain the X and Y extents (hence the need for a fully preserved flat file with nulls). Alternatively: Things to try inside ErMapper 1. Create an image that shows ONLY the pixels you wish to edit. 2. Save this image as a Virtual dataset. 3, Use Process > Raster Cells to Vector Polygons to create polygons around the chosen data values saved in the Virtual dataset. 4. Use Edit > Annotate Vector Layer > Edit Object Attributes to give a common name to the vector polygons using Map Composition Attribute > Apply All 5. If necessary edit the polygon file to obtain the required subset of polygons. 6. Save the named polygons as a Raster Region inside your target raster file. 7. Use the Standard Formula > Inside region polygon test to alter the properties of the pixels you wish to edit (You can alter NULL in the Inregion test formula to a suitable data value if you require). Good Luck Philip Mulholland [EMAIL PROTECTED] --------------------------------------------------------------------------- This e-mail and any attachments are intended only for the addressee named above and may contain confidential or legally privileged information. If you are not the intended recipient, any disclosure, reproduction, copying, distribution or other use of this communication is strictly prohibited. If you are neither the addressee nor a person responsible for delivering this message to the addressee, please notify the sender immediately and delete this e-mail. You are also advised - as is required by law - that any messages generated, received or stored on the e-mail system of Agip (UK) may be intercepted by Agip (UK), acting as system controller. --------------------------------------------------------------------------- ----------------------------------------------------------- To make changes to your subscription, please visit our website, http://www.ermapper.com/technicl/ermapperl/index.htm
