Topics

The Riverside County TLMA now offers most of their GIS data online for free. You can download it by following this link: http://www.tlma.co.riverside.ca.us/online/content/gis_downloads.aspx

You will need access to software that can read ESRI file Geodatabases in order to use it however.

I just saw on the Census Bureau site that TIGER 2008 was just made available on 12/8/08. I downloaded two counties in California and it looks like San Bernardino has been realigned and Riverside so far has not been.

You can find the data here:
http://www.census.gov/geo/www/tiger/tgrshp2008/tgrshp2008.html

This is my first post here so hopefully these questions haven't been addressed elsewhere. I'm not sure if I'm using proper terminology so I hope I make some sort of sense.

I have been successfully making street maps using GIS data from various sources for the past several months now. They work in several Garmin units including my GPSMap 60CSx, GPSMap 76S and the GPSMap 76CSx that I have at work. I use ArcGIS to edit the data and reproject it to UTM, then I import it into GPSMapEdit to compose the map, and then use cGPSMapper to process a Garmin IMG file. I use SendMap to transfer the IMG file to the Garmin units.

So far, I have been using county boundaries as the borders for these maps (since that is how the GIS data that I am using is distributed) but I don't think that is the most ideal way to break them up. For those of you who are making maps, what sort of boundaries are you using to create each individual map? For example, are you using something like the 1:250k or 1:100k USGS topo map boundaries or perhaps something similar?

I'd also like to add contour lines to my maps now that I have the process almost completely figured out now. I have downloaded the DEM data for the area that is covered by the 1:100k USGS topo map for San Bernardino, CA and DEM2Topo chokes on it when it gets near the end of the process. I have it set for 1000 ft major, 500 ft intermediate, and 40 ft minor contours. The process completed when I accidentally had it set for meters instead of feet and it also completes when I process DEMs that are half the size of the 1:100k area that I am trying to cover.

I guess the two questions are somewhat interrelated. How big of an area to you guys use for each of your maps and how large of an area will DEM2Topo generate contours for? The county I live in is rather big (area wise) so I was trying to cover as large an area as possible. Perhaps there is an easier way that I have yet to discover for splitting my data down into smaller map tiles.

Thank you.