Subject: WGS84 and UTM Posted: 2/3/2014 Viewed: 32879 times
Dear colleagues,
I wanted to load some layers using UTM but looks like WEAP is not able to recognize it. I've read in the forum that unloading WEAP's reference layers, which are in WGS84, allows you to visualize layers in UTM, BUT:
Does it mean that the project after doing this is working in UTM??
Would the 'kmz export' tool write coordinates in UTM??
or working like this is just a visualization trick??
In any case, if I try to unload WEAP's reference layers, it comes out a message saying that I need at least one refence layer, which is in WGS84, so I can't define any other.
So how could I unload all of them to get my project just in UTM??
Thanks very much in advance,
i.
Dr. Devaraj de Condappa
Subject: Re: WGS84 and UTM Posted: 2/4/2014 Viewed: 32843 times
My general advice is to try to always use GIS files in WGS84 for universality and enable 'on-the-fly' projection in your GIS software (if you want to view in projected for instance).
Anyway, to go back your question, to open UTM GIS files in WEAP, it seems indeed to work if you remove the layers which are there by default. To do so, 1st load your UTM layer, then remove all the default layers in WGS 84, then you will have to reset your Area Boundaries and it should work. I presume now that WEAP has its own spatial reference system set to the UTM (ie projected meters), so every next GIS files you open should be in the same projected UTM.
I don't really know about your other question (export kmz) but to my knowledge Google Earth also works in WGS84 so I always save kmz files in WGS84.
Hope it helps.
Mr. Iban Ameztoy
Subject: Re: WGS84 and UTM Posted: 2/5/2014 Viewed: 32833 times
Thanks for your answer Devaraj,
It is clear for me that in order to avoid confusions it would be better to work always with WGS84. The question was that I was also trying to avoid reprojections of my original data, and in this sense I was having problems to load layers in a certain PCS, so it is not only about having UTM but having defined well the proper Projected Coordinate System (?).
Now it is a bit more clear that when unloading the reference layers and defining the new area WEAP automatically takes UTM as the base reference, so at the same time that's why probably asks to identify the UTM zone when exporting the file to kmz.
Maybe I haven't explained well enough about the kmz export issue, but I was quite confused about the way WEAP works with different coordinate systems.
Mr. Markus Huber
Subject: Re: WGS84 and UTM Posted: 2/12/2014 Viewed: 32723 times
In general, WEAP doesn't reproject Datasets and so doesn't care about what Coordinate System and Projection you use. You may use any, even your own customized CS and Projection. The only thing that matters is that all Vector or Feature Layers are consistent to each other.
ESRI shape files store different information in various files:
*.shp: x and y Coordinates of each Feature or Vertex
*.shx: Coordinates of the surrounding rectangle of each Feature
*.dbf: Feature Attributes
*.prj and *.aux: the definition of the projection
*.sbn and *.sbx: definition of joins and relates
*.xml: Metadata
Depending on the type of data, there could be additional files.
WEAP ignores all files except shp, shx and dbf.
If you want to use a CS other than Lat/Lon, it is important to load one layer in you own CS and delete the default layers (as Devaraj explained) prior to editing the Schematic. As the Nodes and Lines in the Schematic are also stored as a shapefile with the coordinates based on the area boundaries, the Shematic would not ne consistent to your background layers and mislocated.
Mr. Iban Ameztoy
Subject: Re: WGS84 and UTM Posted: 2/13/2014 Viewed: 32691 times
Thanks Markus for your answer.
My final purpose in terms of projections, etc. was/is to correctly export my digitized schema to a kmz so I can convert it to a shp and integrate it in a GIS. So I understand that WEAP does not care about coordinate systems and projections, but I would say that if you want to correctly and accurately export your schema, then you would need to better define what you're doing rather than using anything...
In any case, I'm now working with WGS84 so I haven't had any problem.
