Latest Contributions by LamaZip

I have downloaded 2 chlorophyll maps which generally have cell values of 0-255.  How can I convert these into real world values?  Following the instructions linked here and here, I have been unable to convert the byte value (0-255) to geophysical values (0-64 mg m3) Details I have downloaded L3 choloprhyll data maps. I have extracted and attempted to convert the cell values in R, with no luck.  Is this possible in Arcmap and how would it be achieved?  # DN = digital number / cell value / cholorphyll L3 data  # value = 10^ [(DN * slope) + intercept] # raster = Modis cholorphyll sattelite image # Code ran in R ((values(raster)* 0.015) -2.0)^10) # Does not return real world values (values between 0-64 mg m-3) Linked below is one of the raster images I have attempted to convert into real world geophyiscal values, which was downloaded from Giovanni (after clicking the link, click plot, select an image and download as a TIFF. Attachment limits prevent me from directly uploading image. OR just download image attachment in comment below) Question: How can I convert the pixel values (0-255) of a cholorphyll L3 TIFF image into real word values, using Arcmap? ... View more

I have downloaded a SST image of the United Kingdom. It is in PNG format with no coordinate system.   I know the dimensions of my image and its lat/long range. However, i'm not sure what approach to take in Arcmap to set the co-ordinate system.   There is a web-page describing how to convert image co-ordinates to latitude/longitude but it is beyond my scope link   The image is apparently produced in Mercator projection   Note, this will need to be carried out on multiple rasters, so a automated/batch approach, which isn't interactive or manual, is required 1. is there anyway to automatically convert the XY pixel co-ordinates to lat and long, by knowing the lat/long range of the image and the dimensions? 2. If not, how would one do this calculation to convert image XY co-ordinates to lat/long in Arcmap / Python?    Details of Image Dimension   1596 x 1617 BPP 8 Latitude range  47 — 62.999108 Longditude range    -15 — 13 Pixel dimensions    1.100149 x 1.100149 ... View more

I have downloaded a SST image of the United Kingdom. It is in PNG format with no coordinate system. I know the dimensions of my image and its lat/long range. However, i'm not sure what approach to take in Arcmap to set the co-ordinate system. There is a web-page describing how to convert image co-ordinates to latitude/longitude but it is beyond my scope link The image is apparently produced in Mercator projection Note, this will need to be carried out on multiple rasters, so a automated/batch approach, which isn't interactive or manual, is required Details of Image Dimension   1596 x 1617 BPP 8 Latitude range  47 — 62.999108 Longditude range    -15 — 13 Pixel dimensions    1.100149 x 1.100149 ... View more