Latest Contributions by DavidOrchard

I am trying to digitize an old map. The projection is Lambert Conical Orthomorphic, It is a southern hemisphere map I  georeference the map (it is a scanned image, I've tried various projections) it appears to georeferecnce OK. But when I try to digitize various features as a layer, the digitised vector layers are (flipped over and spun thru 180 degrees). Advice desperately wanted,  Anyone have any ideas? thanks ... View more

I'm not sure which tool to use. I've a DTM based on a 50cm grid and a polygon vector layer, I wish to extract the maximum value from the DTM layer for each polygon and insert into a column (MaxZ) in the vector layer. Could somebody advise the best tool to use? ... View more

I need a little guidance/ help. I've two  DSMs of the same area taken on different dates showing major erosion. I want to calculate the volume of material lost (old DSM minus new DSM). The surface volume tool assumes a flat plain for the second surface. Any ideas world be appreciated. thanks David ... View more

DAK, is it possible to display the ArcMAP Data view and the ArcMAP layout view simultaneously in different windows? ... View more

Sorry it's such a basic problem. I've a shape file with around 15million rows and around 20 columns. I want to extract a subset (50k rows) of this data based on geographic location. (i.e if it occures inside a predifined area). Every method I try ArcGIS closes down. (I've 10.1 on win 7 and 9.3 on XP). Could some kind soul advise me the best way to proceed? TIA ... View more