Converting GeoPDF to GeoTIFF

Written by charlie   
Wednesday, 24 June 2015 13:56
At times, mapping data is only available in a format that is not ideal for use within GIS. A Geospatial PDF or geoPDF is one of these formats, its a great for the end user of the map, but not for utilizing or importing the data found within the map in to a GIS system. However, there are times when you only have access to a GeoPDF and not the original source data, and must use what you have on hand. Once again, the free and Open Source Geospatial Data Abstraction Library (GDAL) comes through in a pinch, with its built in tools, gdalinfo and gdal_translate.

For a comprehensive howto, the USGS's guide Converting US Topo GeoPDF Layers to GeoTIFF is good place to start.
 
 

Minnesota leads Nation in wetlands conversion

Written by charlie   
Sunday, 21 June 2015 23:42
Between 2008 and 2012 Minnesota converted almost 25,000 acres of wetlands to crop land, largely as a result of higher crop prices due to the push for ethanol. The research, done by the University of Wisconsin-Madison used satellite data to identify land which had been converted.

The original article is here
 

Roses and Iris'

Written by charlie   
Sunday, 21 June 2015 02:11
Its spring and both gardens and wetlands are in full bloom. Out around Hempstead Lake Park on Long Island, the scent of roses accompanied me for a portion of the three mile lake loop. Hempstead Lake, the largest lake in Nassau County is largely natural, but by no means pristine; traversed by the Southern State Parkway, and surrounded by suburbia in all directions. Curious as to what created this terrific scent, I detoured onto the shoreline trails choked with poison ivy. Upon arrival, I scowled at the source of the scent, thickets of multiflora rose in bloom with its signature, one inch white flowers.

Multiflora rose, despite its wonderful scent, is an invasive species, found in both wetlands and uplands, excludes native plants from growing by crowding them out of their natural habitat. The thickets these roses bushes create can become so large and dense they have been planted roadside as a natural crash barrier.

Its cousin, the swamp rose (Rosa palustris) is found in moist soils, but can also thrive in drier soils, is also very fragrant, found with larger, pink flowers. It is an anolomy among roses, which almost as a rule, do not tolerate "wet feet".

Moving further down the trail, I was not able to find any blue flag, (Iris Versicolor), the defacto natural wetland iris found in the Northeast, but I did discover a stand of yellow iris' (Iris pseudacorus) on the north eastern shore of the lake. The yellow iris is the only yellow iris in the US and will grow in upto 1 foot of water. It is also considered invasive for the same reasons as the multiflora rose, it excludes all other plants from the area by growing large stands of plants.

Yellow Iris Wetland

Blue Flag Iris - Wetland

Multiflora Rose

Swamp Rose

Further Reading:

Invasive Yellow Iris

Swamp Rose

 
 
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