Frequently Asked Questions: GIS Maps

Aside from sending your Regional Office a letter stating this, a GIS capability discussion should occur during the annual EAP coordination meeting. When or if any EMA(s) acquire GIS capability, then a plan and schedule should be submitted outlining when digitization of the inundation map will take place.

No, you only need to have the inundation area digitized that can be utilized by the one EMA. However, you might find a cost savings in the long-term with having your entire area done at one time, should the other EMAs become GIS capable.

Yes, the line should, at a minimum, span between the left and right extents of the inundation area.

The electronic (raster) copy of the map should be at the same scale as the paper copies included in the EAP. The scale required for the paper maps is discussed in Chapter 6 of the Engineering Guidelines. The map should not only include the points which make its georeferencing possible, but also any important features which might be helpful for EMAs.

Yes, provided that the file format used can meet all of the technical specifications listed in Chapter 6, and the format can be imported and viewed using ESRI's ArcGIS software. Many design software packages use an imaginary grid to plot drawings on. Keep in mind that this imaginary XY grid may not be translatable into a true coordinate system, such as the required Albers Equal Area Conic projection.

Yes, as it is explicitly stated in the General Specifications portion of the letter, each file must have its own metadata file.

No, these points are used exclusively for georeferencing and need not be physical features. A simple point in space with an XY coordinate is sufficient. Please note that distinct features of the project should be marked with points (i.e. powerhouse, remote dike, spillway, etc.), and these points should be placed at the approximate center of the structure.

No. The intent of this initiative is to simply reproduce the current paper maps in a usable GIS format for EMAs and not to obtain cross-section data that can be input to a flood routing program. Cross section files DO NOT need to include topographic information, i.e. a 3-D shapefile.