From: Bruce Young, PAFID
Sent: Thursday, September 23, 2004 2:29 AM
To: Ben Discoe
Subject: RE: VTP download

[...] Our main office is in Quezon City, Metro Manila.  We also have an office in Davao on the southern island of Mindanao.

We've been into mapping for about seven years but have only recently become interested in trying to use hillshading or terrain visualization to enhance our data, which consists mainly of indigenous people's ancestral domain boundaries and their land use.  [...]

As for data availability in the Philippines, the situation is fairly bleak.  We've been able to download SRTM DEMs and Landsat images from the GLCF, but the DEM data is only 90-meter resolution, not good enough for many of the areas we want to represent, which may be only a few thousand hectares.  In a few cases we've digitized the 20-meter contours from 1:50,000 topo sheets, but this is extraordinarily laborious and time consuming.  Also, when we have the contours digitized and tagged with elevations, we don't have the software to be able to generate 16-bit DEMs.  We use IDRISI, but it it's only able to output 8-bit DEM images (it doesn't export USGS ascii DEMs) and these are not of the best quality.  I've tried using Blackart, but with new (free) software if I'm not able to get at least some useable result after a couple hours of fiddling, I get frustrated and give up on it.  There are a dozen or so 30-meter ASTER DEMs available, but these only cover a couple small areas in Mindanao and they have many holes in them.  That's about all I know about  as far as elevation data goes.  There may be more sources, but I'm unaware of them.

As for vector data, complete and reliable data sets are few and far between.  I know of no road or even political boundary data in the public domain that is accurate, updated, or authoritative.  Conservation International last week came out with a CD with, in addition to other data, the shoreline of this entire 7,000-island archipelago digitized from 1:50,000 topographic maps.  Previously available digital shoreline data I think came from the 1:250,000 topo sheets; there were several versions in general circulation, and none of them matched!  I've heard that this new data set is intended to become the standard that everyone will use, though I haven't seen it yet.

So that's just a brief and sketchy overview of data availability in the Philippines as we know it.  Commercial GIS firms here may have more and better information on this, I'm not sure.  Feel very lucky that in the United States you have a plethora of high quality data available, the type of data we can only dream about! [...]