Ligger bäckarna rätt i kartan?

Sammanfattning: “Are the headwaters streams at the right position in the map” is a study that has been performed on behalf of Holmen Forest, region Örnsköldsvik. This study will be the basis for deciding if the Hydrology Layer Property map or Holmen Forest map will be used for planning nitrogen fertilization in forestry. The background to this study is that nitrogen fertilization near water will increase the risk of nitrogen leaching out into the water systems, which has a negative impact on the environment. The headstreams positions have been recorded in the field with a GPS and the data analyzed in the geographic information system ArcMap. The result shows that the difference between the Property map and Holmen Forest map hydrology layers is only 0,1m2/m in area deviations. From this perspective, the difference between the two maps is negligible when considering which to use during nitrogen fertilization. The largest source of error in the study is GPS accuracy.