I am mapping the prevalence of Schistosomiasis in more than 300 villages in Mali (West African country) for my GIS class project that is due next week. My data are unprojected (decimal degree). Since I didn�??t have a basemap of Mali, First, I added a shapefile of Africa that I downloaded from this website http://www.fao.org/geonetwork/srv/en/main.home Then, I used the �??select by attributes�?� option to create the Map of Mali. The coordinates system is label as <Undefined> in the data source, Next, I added the Excel file to the table of contents and display the X Y data. I exported this data as a shapefile still in �??decimal degree�?� When I right click the Layer, In the Data Frame Properties under coordinates System, I have this message �??Unknown, Note: one or more layers is missing spatial reference information. Data from these layers cannot be projected.�?� Can someone please tell me (1) Which Projected Coordinate System is usually used for data in Mali? I want to be able to project the data in feet or meters, not in decimal degree, because I have some further analysis to do. (2) Where can I obtain a shapefile of Mali with administrative boundaries (3) Where can I obtain a shapefile for Mali rivers Thank you
I believe tht you may obtain the data from the adminstrative offices of county or the region.
However if you are using the ArcGIS, you may change the projection units to what ever uit you wsih form the list of Linear units. Below are the workflow to change the linear unit of the projection while projecting the data from one projection to another.
1) Open ArcCatalog 2) Go to ArcToolbox > Data Management Tools > Projections and Transformations > Feature > Project. 3) Open Project Tool 4) Add your data as Input feature. 5) Specify the output loation for the Output data 6) Specify the Output Coordinate System of the data to which it has to be projected 7) Here you go to Select > Projected coordinate system > And choose some desired projection and Click OK. 😎 Now you would find the Projection was selected and loaded in the Spatial reference properties window. 9) You would also find a modify button, just below the Select Button through which you may change the unit of the projection. 10) Click Modify > Linear Unit > Change to any unit you want and click Ok 11) Then you may also need to select certain transformations according to the prjection and your area of interest.
Please refer the below link for the list of transformation and how to use it.
