Archive for the ‘GIS’ Category
Delaware State High Point: Ebright Azimuth
Tuesday, November 2nd, 2010Canadian rockers Moxy Früvous would have you believe that the US state with the lowest highest point is in Delaware. (Moxy Früvous – The Lowest Highest Point from some shady website) In the beginning of the song, they say that they would expect it to be Florida or Louisiana, and they would have been correct had they picked Florida, but they incorrectly went with Delaware. Maybe because of a question in Trivial Pursuit[3]?
In any case, they’re Canadian, so we can give them a break. How many people in the US can even name all of the Canadian Provinces and Territories? I tried to do it once in alphabetical order, and found that there are a lot of them that start with N: New Brunswick, Newfoundland and Labrador, Northwest Territories, Nova Scotia, and Nunavut. 38.4% of the Provinces and Territories in Canada start with an N! I found this interesting enough that I made a pie chart about it.
The Canadian Province with lowest highest point is Prince Edward Island, at 459-466 feet (Sources Vary) [2][4]. This is still higher (but not much higher) than Delaware’s highest point [1].
Anyway, I have been interested in state highpointing for a little bit, and figured Delaware would be an easy one to knock off my list.
After a trip to White Clay Creek State Park to go biking and find the Arc Corner Monument (unsuccessfully, after my bicycle got a flat tire 8 miles from where we parked), we decided to take a detour on our way home to find the Delaware State High Point.
I had done research on it in the past, and had come across this site. It has a cool map showing that there is land near the official high point is actually slightly higher. The Delaware State High Point Wikipedia Entry claims this land was added later for drainage reasons, but it isn’t a natural high point, and therefore doesn’t count. It was easy to find, and near route 202 in Wilmington, so it was close enough to being on our way.
We arrived at the high point around 7:30pm on Halloween, and we were greeted by costumed Trick-or-Treaters. We took a drive into the trailer park and took a photo of a field that is near the areas depicted to be above the surveyed high point (Those specific areas are all private lawns, so we didn’t want to be too intrusive). We also drove over to the official marker sign and took a photograph. It was quite dark, and it required me to strategically position my car’s headlights on a nearby street to illuminate the sign well enough for the photograph.
 The actual highest point is in this photo.. somewhere |
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Pennsylvania’s Highest Point: Mount Davis
Wednesday, July 7th, 2010
The observation tower at Pennsylvania's highest point, Mount Davis.
The Mount Davis high point is located on a mountain ridge called Negro Mountain. It is about 4.37 miles from the Pennsylvania / Maryland border, and just over 16.5 miles from the Pennsylvania / Maryland / West Virginia tripoint. My GPS showed the location to be 39.785841°N, 79.176596°W, with an elevation of 3,362 ft. Which is much more accurate of an elevation than I normally expect from my GPS. According to the Wikipedia article on the point, the coordinates are 39.786111°N, 79.175833°W.
My attempt at an artistic photo of a windmill at the Casselman Wind Power Project
We saw a few interesting sites on our way to the High Point. The first of which was the Casselman Wind Power Project. We decided to get out and explore the wind mill area. I had never been that close to a wind farm before. It is a really amazing source of power, and it appears to be located in a fairly suitable location, as most of the turbines were turning.
The road sign marking the state's highest point.
Ken climbing on Baughman Rocks
What I assume is the Highest Treetop in Pennsylvania
Topographic map of the area around Mount David
Sideling Hill Gap Road Cut
Appalachian Brewing Company
No trip is complete without a stop at a local brew pub. We stopped at the Appalachian Brewing Company just outside of Camp Hill, PA for some excellent beer, rosemary bread sticks, salad, and peanut butter pie! The waitress explained to us that they are not located in the borough of Camp Hill because the borough is a dry town. That is the first I had ever hear of a Pennsylvania municipality being dry!
I got to learn a lot about Pennsylvania on this trip, and am looking forward to highpointing in NJ and DE in the near future. I also came across an excellent webpage with highpoints for all of Pennsylvania’s 68 counties. I hope to get to a few of these this summer!
ESRI Shapefile Shapes and Parts and KML analogies
Friday, July 2nd, 2010Determining if a Polygon is drawn clockwise or counterclockwise
Wednesday, February 10th, 2010“The neighborhood to the right of an observer walking along the ring in
vertex order is the inside of the polygon”. Meaning that all normal or
“clean” polygons are drawn in a clockwise fashion. When it comes to
holes in the polygons, these are defined by a counterclockwise path
delineating the polygon.
determining if a polygon is an additive vector or a subtractive one is
to determine the direction in which the polygon is formed. ESRI
Shapefiles do not support polygons that cross their own lines, which
makes calculating data with them a bit easier. One method to determine
the direction the polygon is formed is by using Green’s Theorem.
This method would require one to take the current coordinate (x1,y1),
and the next one (x2,y2), and apply the following formula:
∑(x2-x1)*(y2+y1). For each line segment, one would then need to add
the result to a running total, and if the number ends up being
positive, the polygon is clockwise, and if it is negative, the polygon
is counterclockwise.
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KML code:
(Figure 2.1) |
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Using the KML code above to create the triangle above:
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KML code:
(Figure 2.2) |
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Using the KML code above to create the triangle above:
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CloudMade Tile Request Heat Map
Wednesday, April 8th, 2009
I love heat maps, and I think OpenStreetMap.org is an amazing idea. This is a heat map of the tile usage. It’s cool to see bright spots in South America and Africa. I’m curious as to why there isn’t a bright spot near Perth, and I guess I’ll need to sign in to get info on New Zealand, Eastern Australia, and Alaska. What’s with these maps that are always cutting on the Water Hemisphere anyway?
m.k.ge•o•mat•ics |ˌjēəˈmatiks| › CloudMade Tile Request Graphics.
